PREVENTINGRECURRENTANKLE

SPRAINSTHEIMPLEMENTATIONEFFECTIVENESSOFTHE‘STRENGTHENYOUR

ANKLE’APP

MiriamvanReijen

2

ThestudiespresentedinthisPhDthesiswereconductedwithintheAmsterdam

CollaborationonHealth&SafetyinSportsandtheAmsterdamPublicHealthResearch

Institute,attheDepartmentofPublic&OccupationalHealthoftheAmsterdamUniversity

MedicalCenter,locationVUmc,theNetherlands.

TheworkpresentedinthisthesiswasfundedbytheDutchorganisationforhealth

researchanddevelopment(ZonMW),grantnumber525001003.

Englishtitle:Preventingrecurrentanklesprains:theimplementationeffectivenessofthe

‘strengthenyourankle’app.

Nederlandsetitel:Hetvoorkomenvanrecidiefenkelletsel:deeffectviteitvande‘Versterk

jeEnkel’app.

ISBN:978-94-6323-440-5

Coverpicture:BarbaraKerkhof.Reproducedwithpermissionofthecopyrightowner.

Coverdesign:EviannedeGroot

Printedby:Gildeprint–Enschede,theNetherlands

©2018MiriamvanReijen,theNetherlands

Allrightsreserved.Nopartofthisthesismaybereproducedortransmittedinanyformor

byanymeanswithoutpriorpermissionfromtheauthor,or,whenappropriate,the

publishersofthearticles.

3

VRIJEUNIVERSITEIT

PREVENTINGRECURRENTANKLESPRAINS

THEIMPLEMENTATIONEFFECTIVENESSOFTHE‘STRENGTHENYOUR

ANKLE’APP

ACADEMISCHPROEFSCHRIFT

terverkrijgingvandegraadDoctorofPhilosophy

aandeVrijeUniversiteitAmsterdam,

opgezagvanderectormagnificus

prof.dr.V.Subramaniam,

inhetopenbaarteverdedigen

tenoverstaanvandepromotiecommissie

vandeFaculteitderBewegingswetenschappen

opdinsdag15januari2018om11.45indeaulavandeuniversiteit,

DeBoelelaan1105

door

MiriamvanReijen

geborenteUtrecht

4

promotor:prof.dr.W.vanMechelen

copromotor:prof.dr.E.A.L.M.Verhagen

5

TABLEOFCONTENTS

CHAPTER1 Generalintroduction

7

CHAPTER2 Theimplementationeffectivenessofthe‘Strengthenyourankle’

smartphoneapplicationforthepreventionofanklesprains:designofa

randomizedcontrolledtrial�

13

CHAPTER3 CompliancewithSportInjuryPreventionInterventionsin

RandomisedControlledTrials:ASystematicReview

27

CHAPTER4 Increasingcompliancewithneuromusculartrainingtoprevent

anklespraininsport:doesthe‘Strengthenyourankle’mobileAppmakea

difference?Arandomisedcontrolledtrial

71

CHAPTER5 The"Strengthenyourankle"programtopreventrecurrent

injuries.Arandomizedcontrolledtrialaimedatlong-termeffectiveness.

87

CHAPTER6 Preventingrecurrentanklesprains:IstheuseofanAppmore

cost-effectivethanaprintedBooklet?ResultsofaRCT.

101

CHAPTER7 Evidencebasedanklesprainpreventioninyourpocket?Amixed

methods approach on user’s perspectives, opportunities and barriers of the

Strengthenyourankleapp.

117

CHAPTER8 GeneralDiscussion

135

SUMMARY

145

SAMENVATTING

148

DANKWOORD

151

OVERDEAUTEUR 153

6

7

CHAPTER1

Generalintroduction

one.

8

Aminorinjury?

Weexercise for the love of sport, for keeping fit, for losingweight or becauseweenjoy

spendingtimewithfriends.Whateverthereason,thereisnodiscussionthatregularexercise

benefits our health: both physically and mentally [1]. One could argue that the only

disadvantageofbeingphysicallyactiveistheriskofgettinginjured[2].Whileexerciseis

generallyadvocatedtocontributetooverallwell-being,itcomeswithahealthrisk,bothfor

theindividual,asforsocietyasawhole[2].Thatthisriskissubstantialisclearlyillustrated

bythefollowing:theDutchOBiNresearch(ongevallenenbeweginginNederland:accidents

and exercise in the Netherlands) calculated that the Netherlands has a population

participatinginsportofjustover12million.These12millionpeoplewereconfrontedwith

no less than 4.5 million injuries in 2013 only; 3.2 Million (69%) of those injuries was

classifiedasacute,and1.9millioninjuries(42%)wasmedicallytreated.Thebodypartsthat

aremostoftenaffectedbyaninjuryarethekneeandtheankle,withrespectively970.000

and680.000injuries.Thesinglemostcommoninjuryisananklesprain[3],whichmakesup

85%ofallankleinjuries(480.000).Apreviouscost-effectivenessstudy[4]hasshownthat,

disregardingtherequirementofmedicaltreatment,themeantotal(directandindirect)cost

of one ankle sprain amounts to approximately€360. This givesa rough estimate of the

annual(201C)sportsrelatedanklespraincostsintheNetherlandsof€183.6M.Inaddition

tosocietalcosts,thereisextensiveevidencethatthereisanuptotwofoldincreasedriskfor

anklere-injuryduringthefirst-yearpost-injury[5,6].Inabout50%ofallcasesrecurrences

mayresultindisability,canleadtochronicpainorinstabilityandmayrequireprolonged

medicalcare[5].Assuch,anklesprainsposeasignificantburdentotheindividualathlete

andtosociety.

Anefficacioussolutionathand

Previous research has shown that bothexternallyappliedankle supports (i.e. taping or

bracing), as well as neuromuscular training programs are successful in preventing

recurrentcasesofanklesprain,bothfromaneffectiveness,aswellasacost-effectiveness

perspective [7,8,9].While suchmeasures have not been linked to a primary preventive

effect,thesemeasurescanreducetheincreasedriskofrecurrentinjurytothesamelevelas

never injured athletes. Therefore, in most current treatment guidelines, secondary

preventive measures - preferably through continued neuromuscular training - are

recommendedafterrehabilitation.Notonlyhavethesesecondarypreventiveeffortsshown

to be efficacious, they are also associatedwith high short-term (i.e. 1 year) returns on

investment.Theneuromuscularprogramthatisthecentreofthisthesishasbeenlinkedto

a€100net returnforeachinterventionpackagehandedout[8].The ‘VersterkjeEnkel’

neuromuscular training program consists of six exercises taking all together eighteen

minutes,thatshouldbeperformedthreetimesaweekoveraneight-weekperiod.Withthe

useofadetailedscheduletheuserischallengedtoincreasethedifficultyoftheprogram

overtime.

9

Efficaciousbutwithouteffect

Althoughthisprogramhasbeenshowntobeeffectiveinreducingrecurrentanklesprains,

large-scalecommunityuptakeofthepreventivemeasureislaggingbehind.Thisisdespite

the high prevalence of ankle sprains, and despite an active stand by various Dutch

stakeholders–suchassportsfederations,generalpractitioners,physiotherapistsandthe

NationalOlympicCommittee-inimplementingtheneuromusculartrainingprogram.The

lackofwidespreaduptake,resultsinthefactthatanklesprainscontinuetomakeupalarge

percentageofallsportinjuries.TheDutchinjuryrates,registeredbytheDutchConsumer

SafetyInstituteVeiligheidNL[3],showedthatanklesprainrateshavebeenconsistentover

thepastyears.

Whiletheneuromuscularprogramhasbeenproven(cost-)effective[8,9]compliancewith

theprogramispoor[9].Infact,thepreventiveeffectinthesestudieswasachievedonlyin

a subsample of compliant participants showing significant population effects.However,

analysesweredonefromanintention-to-treatapproach,implyingthatthereismuchtogain

atbothanindividualasapopulationlevelbyincreasingcompliance.

Acontemporaryapproachtotheproblem?

Ithasbeen increasinglyacknowledged thatpreventive interventionsshouldnotonlybe

basedonevidence-basedmedicinebutshouldincludealsouser’sopinionsandbarriers[15,

16]. In this thesis, the study population varied from elite athletes aiming for top

performance to elderly peoplewhosemainaimwas tocontinue theiractivities of daily

livingwithoutdifficulties.Interventionsforsuchadiversepopulationshouldbesuitedfor

all those involved. In previous studies from this research group it was concluded that,

althoughtheprogramwaseffective,methodsofimplementationshouldbeimprovedtoend

upwithaninterventionwiththelowestbarrierspossibletoeverydayuse[2].

Inanattempt tobridge this so-called implementationgap,VeiligheidNL looked into the

possiblefeasibilityofnew(social)mediaininjuryprevention.Afreelyavailableinteractive

App(‘VersterkjeEnkel’;availableforiOSandAndroid)wasdevelopedthatcontains-next

to general advice on bracing and taping - the cost- effective neuromuscular training

programpreviouslydevelopedby this researchgroup. It isgenerallyassumed that such

interactive, online andmobilemethods of information transfer are theway forward in

preventionandimplementationefforts.However,thishasnotyetbeenformallyestablished

fortheuptakeofevidence-basedinjurypreventivemeasures.Whilenumerousmobileapps

areavailable,only fewcontainpreventionadvice that isactually supportedbyscientific

evidence[17].Furthermore,althoughuserreviewsarepositive-the‘VersterkjeEnkel’App

has not been evaluated against the well-studied ‘regular’ approach to advocate the

neuromuscular training program by making use of printed and DVD materials. If the

‘Versterk je Enkel’ App indeed does increase intervention uptake, thiswill provide the

necessaryvalidationtofurtherdevelopandenhancethispromisingroleofnewmediain

theimplementationofpreventivemeasuresandinterventions.

10

Theoutlineofthisthesis

Theaimofthisthesiswastoevaluatetheimplementationvalueofthe‘VersterkjeEnkel’

App as compared to the usual practice of providing injured athletes with ‘ordinary’

materials. The premise was that use of the ‘Versterk je Enkel’ App would increase

compliance to the prescribed programand, consequently, would decrease ankle sprain

recurrenceincidence.

Chapter2 contains the studydesign article thatwas publishedduring initiation of thecurrentstudy.

In chapter 3 one can find a review study inwhich themain features of 100 RCTs aredescribedthatdealwithsportinjuryprevention.Themaintopicofconcerned‘howsport

injurystudiesdealwiththeconceptofcompliance’.Itwasalsolookedathowcompliance

was defined, measured and reported and what effect compliance rates had on the

effectivenessofpreventiveinterventions.

Chapter4Thestudypresentedinthischapterevaluatedwhetherthe‘VersterkjeEnkel’applicationresultedininahighercompliancetothetotheembeddedprescribed8-week

exerciseprogram,andwhethertherewasadifferenceinprogrameffectivenessbetween

groupsofusersthathadusedtheprograminitsoriginalpaperform,versusaninteractive

appform.

Chapter5reportsthelong-termstudyresultsofa12-monthfollow-upduringwhichtheneuromuscular training program was no longer continued. During these 12 months,

recurrentinjuriesinthestudypopulationwereanalysedbymonthlyonlinequestionnaires.

Themainquestionofthischapterwasiftherewasadifferenceinanklesprainrecurrence

incidenceratesbetweenthegroupapplyingthe‘VersterkjeEnkel’Apporthegroupusing

writtenmaterials.

Inchapter6astudyisdescribedinwhichthecost-benefitoftheinterventionwasanalysed.Thischapterfocusedontwoquestions.Firstly,isthereadifferenceindirectandindirect

costsduringa12-monthfollow-up,betweengroupsapplyingthe ‘VersterkjeEnkel’App

and written materials? And secondly, is there a difference in ankle sprain residual

complaints(i.e.instability,feelingofgivingway,pain,andcontinuedsportsparticipation)

after a 12-month follow-up, between groups applying the ‘Versterk je Enkel’ App and

writtenmaterials?Thischaptergivesinsightinthecost-effectivenessoftheinterventionas

comparedtousualcare.

Chapter7presentsaqualitativeevaluationoftheneuromusculartrainingprogramwhichis based on semi-structured interviews and open questionnaires. By means of the

interviews and open questionnaires, the barriers and facilitators that affected program

compliancewereevaluated.Inaddition,thesubjectiveuserexperienceofthe‘Versterkje

Enkel’Appandthewrittenmaterialswasexamined.

Finally, in chapter 8 the general discussion presents an overview of themain results,discussesmethodologicalissuesandprovidessuggestionsforfutureresearch.

11

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3. ConsumentenVeiligheid.Enkelblessuresdoorsport.Availableat:http://www.

veiligheid.nl/sportblessures/kennis/cijfers-over-sportblessures.VisitedOctober28,

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4. VerhagenEALM,HupperetsMDW,FinchCF,etal.Theimpactofadherenceon

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7. VerhagenE,BayK.Optimisinganklesprainprevention:acriticalreviewand

practicalappraisaloftheliterature.BrJSportsMed.2010;44(15):1082–1088.

8. HupperetsM,VerhagenE,HeymansM,etal.Potentialsavingsofaprogramto

preventanklesprainrecurrence:economicevaluationofarandomizedcontrolledtrial.

AmJSportsMed2010;38(11):2194–2200.

9. HupperetsM,VerhagenE,VanMechelenW.Effectofunsupervisedhomebased

proprioceptivetrainingonrecurrencesofanklesprain:randomisedcontrolledtrial.BMJ

2009;339:b2684.

10. KluglM,ShrierI,McBainK,etal.Thepreventionofsportinjury:ananalysisof

12,000publishedmanuscripts.ClinJSportsMed.2010Nov;20(6):407–12.

11. McKayCD,VerhagenE.Complianceversusadherenceinsportinjuryprevention:

whydefinitionmatters.BrJSportsMed50:7:382-383

12. SteffenK,EmeryCA,RomitiM,etal.Highadherencetoaneuromuscularinjury

preventionprogramme(FIFA11+)improvesfunctionalbalanceandreducesinjuryriskin

Canadianyouthfemalefootballplayers:aclusterrandomisedtrial.BrJSportsMed.2013

Aug1;47(12):794–802.

13. SabatéE.AdherencetoLong-termTherapies.WorldHealthOrganization;2003.

12

14. SchulzKF,AltmanDG,MoherD.CONSORT2010statement:updatedguidelinesfor

reportingparallelgrouprandomisedtrials.BMCMed.2010;23(340):c332.

15. HansonD,AllegranteJP,SleetDA,FinchCF.Researchaloneisnotsufficientto

preventsportsinjury.SportsMed2014:48:682-684

16. GreenL.Fromresearchtobestpracticesinothersettingsandpopulations.AmJ

HealthBehav.2001.35:165-178

17. VanMechelenDM,VanMechelenW,VerhagenEALM.Sportsinjurypreventionin

yourpocket?!Preventionappsassessedagainsttheavailablescientificevidence:areview.

BrJSportsMed2014.48:878-882

13

CHAPTER2 Theimplementationeffectivenessofthe‘Strengthenyourankle’smartphoneapplication

forthepreventionofanklesprains:designofarandomizedcontrolledtrial�MiriamvanReijen

IngridVriend

VictorZuidema

WillemvanMechelen

EvertVerhagen

BMCMusculoskeletalDisorders2014Digitalobjectidentifier(doi):10.1186/1471-2474-15-2

two.

14

ABSTRACT

Anklesprainscontinuetoposeasignificantburdentotheindividualathlete,aswellasto

societyasawhole.However,despiteanklesprainsbeingthesinglemostcommonsports

injury and despite an active approach by various Dutch organisations in implementing

preventivemeasures,large-scalecommunityuptakeofthesepreventivemeasures,andthus

actualpreventionofanklesprains,islaggingwellbehind.

In an attempt to bridge this implementation gap, the Dutch Consumer Safety Institute

VeiligheidNL developed a freely available interactive App (‘Strengthen your ankle’

translatedinDutchas:‘Versterkjeenkel’;availableforiOSandAndroid)thatcontains-

next to general advice on bracing and taping - a proven cost-effective neuromuscular

program. The ‘Strengthen your ankle’ App has not been evaluated against the ‘regular’

preventionapproachinwhichtheneuromuscularprogramisadvocatedthroughwritten

material. Theaimof the current project is to evaluate the implementation value of the

‘Strengthenyourankle’Appascomparedtotheusualpracticeofprovidinginjuredathletes

withwrittenmaterials.Inaddition,asasecondaryoutcomemeasure,thecost-effectiveness

willbeassessedagainstusualpractice.

Theproposedstudywillbearandomisedcontrolledtrial.Afterstratificationformedical

caregiver, athletes will be randomised to two study groups. One group will receive a

standardizedeight-weekproprioceptive trainingprogram[10,11] thathasproven tobe

cost-effectivetopreventrecurrentankleinjuries,consistingofabalanceboard(machU/

MSGEuropeBVBA),andatraditionalinstructionalbooklet.Theothergroupwillreceivethe

same exercise program and balance board. However, for this group the instructional

bookletisexchangedbytheinteractive‘Strengthenyourankle’App.

Thistrialisthefirstrandomizedcontrolledtrialtostudytheimplementationeffectiveness

ofanAppforproprioceptivebalanceboardtrainingprogramincomparisontoatraditional

printedinstructionbooklet,withtherecurrenceofanklesprainsamongathletesasstudy

outcome.Resultsofthisstudycouldpossiblyleadtochangesinpracticalguidelinesonthe

treatment of ankle sprains and in the use ofmobile applications for injury prevention.

Resultswillbecomeavailablein2014.

Keywords:Mobilehealth,Anklesprains,Ankleinjury,Prevention,Neuromusculartraining

Trialregistration

TheNetherlandsNationalTrialRegisterNTR4027.TheNTRispartoftheWHOPrimary

Registries.

15

BACKGROUND

Anklesprainsarethemostcommonsportsandphysicalactivity(PA)relatedinjury[1-3].

Ithasbeenestimated thatapproximately25%ofall injuriesacrossall sportsareankle

injuries.Ofallankleinjuries85%involvethelateralankleligaments,i.e.acutelateralankle

sprains[3].IntheNetherlands,themostrecentcountofsportsinjuriesshowedthatthere

is an estimated absolute number of 3.7M acute sports injuries each year in a sporting

populationof11Mathletes [4].Ofall annual sports injuries,approximately530,000are

ankle sprains, of which almost 40 per cent requires (para)medical treatment [5]. Our

researchgrouphaspreviouslyshowninacost-effectivenessstudy[6]that,disregardingthe

requirementofmedicaltreatment,themeantotal(directandindirect)costofoneankle

sprainisapproximately€360.Thiswouldgivearoughestimateoftheannualsports-related

ankle sprain costs in the Netherlands of €190,800,000. In addition, there is extensive

evidencethatthereisanuptotwofold-increasedriskforanklere-injuryduringthefirst

yearpost-injury[6,7].Infiftypercentofallcasesrecurrencesmayresultindisabilityand

canleadtochronicpainorinstability,requiringprolongedmedicalcare[8].Assuch,ankle

sprainscontinuetoposeasignificantburdentotheindividualathlete,aswellastosociety

asawhole.

Researchhasshownthatbothexternallyappliedsupports(i.e.tapingorbracingof

theankle),aswellasneuromusculartrainingprogramsareverysuccessfulinpreventing

recurrent ankle sprains, both from effectiveness, as a cost-effectiveness perspective

[3,9,10].Whilesuchmeasureshavenotbeenclearlylinkedtoaprimarypreventiveeffect,

the increased risk of recurrent injury can be reduced to the same level as previously

uninjuredathletes.

Therefore, in all current ruling treatment guidelines secondary preventive

measures-preferablythroughcontinuedneuromusculartraining-arerecommendedafter

rehabilitation. These secondary preventive efforts regarding ankle sprains have been

associatedwithhighshort-termreturnsoninvestment.Theneuromuscularprogramthat

willbethecentreoftheproposedproject,hasbeenlinkedtoa€100netreturnforeach

interventionpackagedistributed[10].

However,despiteanklesprainsbeingthesinglemostcommonsportsinjuryand

despite an active approach by various Dutch organizations in implementing effective

preventive measures and interventions, large-scale community uptake of preventive

measures,andthusactualpreventionofanklesprains,islaggingwellbehind.Thischallenge

can be derived from the Dutch injury rates registered by the Dutch Consumer Safety

Institute VeiligheidNL [5], indicating that ankle sprain rates, treated at hospitals’

EmergencyDepartments, areconsistent over the past years. Inaddition, the previously

mentionedneuromusculartrainingprogram,thathasbeenproveneffective[8]andcost-

beneficial[6],hasbeenshowntohavepoorcompliance[12].Infact,thepreventiveeffect

informerstudieswasachievedinasubsampleofcompliantathletes,neverthelessshowing

significantpopulationeffects.Althoughanalyseshavebeendonefromanintention-to-treat

approach,thisshowsthereisalottogainatanindividualaswellasapopulationlevelby

increasingcompliancetothesesimpleandeffectivemeasuresthatarebeingadvocatedin

varioustreatmentguidelines.

16

Inanattempttobridgethisimplementationgap,VeiligheidNLlookedintothepossiblerole

ofnew(social)mediaandhasdevelopeda freelyavailable interactive ‘Strengthenyour

ankle’App;availableforiOSandAndroid)thatcontains-nexttogeneraladviceonbracing

andtaping-thecost-effectiveneuromuscularprogram,asevaluatedinaprevioustrial.This

Appprovidestheuserwithvideosandaninteractiveneuromuscularexerciseschedule.It

isageneralbeliefthatsuchinteractive,onlineandmobilemethodsofinformationtransfer

arethewayforwardinpreventionandimplementationefforts.However,thishasnotyet

beenformallyestablishedfortheuptakeofinjurypreventivemeasures,and-althoughuser

reviewsarepositive-the‘Strengthenyourankle’Apphasnotbeenevaluatedagainstthe

well-studied‘regular’approachtoadvocatetheneuromuscularprogramthroughwritten

materials. Furthermore, if the ‘Strengthen your ankle’ App indeed does increase

intervention uptake this will provide the necessary validation to further develop and

enhancethispromisingroleofnewmediaintheimplementationofpreventivemeasures

andinterventions.

OBJECTIVES

Theobjectiveofthisrandomisedcontrolledtrialistoevaluatetheimplementationvalueof

the ‘Strengthenyourankle’Appascomparedtotheusualcommonpracticeofproviding

injuredathleteswithwrittenmaterials.

Ourhypothesisisthattheuseofthe‘Strengthenyourankle’Appwillincreasecompliance

totheprescribedneuromusculartrainingprogramand,consequently,willdecreaseankle

sprainrecurrenceincidence.

Specificresearchquestionsthatwillbeansweredare:

• Whatisthecompliancetotheprescribed8-weekexerciseprogramviatheAppandviawrittenmaterial?

• Isthereadifferenceinprogramcomplianceratesbetweenthe‘Strengthenyourankle’Appandwrittenmaterials?

• Is there a difference in ankle sprain recurrence incidence rates during a 12-monthfollow-up, between groups applying the ‘Strengthen your ankle’ App and written

materials?

• Isthereadifferenceindirectandindirectcostsduringa12-monthfollow-up,betweengroupsapplyingthe‘Strengthenyourankle’Appandwrittenmaterials?

• Isthereadifferenceinanklesprainresidualcomplaints(i.e.instability,feelingofgivingway, pain, and continued sports participation) after a 12-month follow-up, between

groupsapplyingthe‘Strengthenyourankle’Appandwrittenmaterials?

• Whatis theparticipants’userexperienceof the ‘Strengthenyourankle’Appand thewrittenmaterials?

17

METHODS

Design

Theproposedstudywillbearandomisedcontrolledtrial.Thestudydesignandflowofthe

athletes are shown in Figure 1. The study design, procedures and informed consent

procedurewere approved by the Medical Ethics Committee (no. 2013/248) of the VU

UniversityMedicalCenterAmsterdam(VUmc),theNetherlands.Thetrialisregisteredin

theNetherlandsTrialRegistry(NTR4027).

Participants

Activeparticipants(athletes),between18and70yearsofage,whohavesustainedanankle

sprainwithinthepasttwomonths,areeligiblefor inclusion.Respondersareexcludedif

theyhavesufferedfromaninjurydifferentfromalateralanklespraininthesameankle

(e.g.fractureoftheankle)inthepreviousyear.Athletesshouldownamobilephonewith

eitherAndroidofiOS.Athleteswillberecruitedthroughparticipatingcaregivingpractices,

websitesfromnationalsportfederations,newsletters,anopeninvitationviatheInternet

andthroughthecommunicationchannelsofparticipatingsportassociations.

STUDYOUTLINE

Randomisationprocedure

Afterathleteshave finishedanklesprain treatmentbymeansofusual care, theywillbe

randomised to one of the two study groupswith stratification for initial treatment (i.e.

medicalornon-medical).Randomisationwilltakeplaceattheendoftreatment.Thiswill

minimise the risk of allocation bias. In addition, thiswill provide room to contact the

medicalcareprovider(s)involvedintheathletes’treatment.Medicalcareproviderswillbe

informedaboutthestudyinwhichtheathletepartakesandwillbeaskedtofollowtheir

usual treatment and/or rehabilitation program. Furthermore, they will be asked to

encourage the athlete to take up their allocated intervention program after treatment

and/orrehabilitationhasceased.

Athletesallocatedtothe ‘regular’ interventiongroupwillreceiveastandardized

eight-weekproprioceptivetrainingprogram,consistingofabalanceboard(machU/MSG

EuropeBVBA),andaninstructionalbooklet.Thisprogramhasbeenshowntobeeffective

inreducingrecurrenceinjuryriskinpreviousrandomizedcontrolledstudies[9,10].

Athletesallocatedtothe‘App’groupwillalsoreceiveabalanceboard(machU/MSG

EuropeBVBA),butthestandardizedeight-weekproprioceptivetrainingprogramwillbe

provided through an interactive smartphone application, which is freely available for

Android and iOS users. These two platforms are the most commonly used operating

systemsonsmartphones(ofallsmartphones79,3%runsonandroid,13,2%oniOS)(18).

Thereby,selectionbiasisconsideredminimal.Allathletesreceivethesamebalanceboard.

Boththeinstructionbookletandthe‘Strengthenyourankle’Appcontainthesametraining

programandsixbasicexercises(Figure2).

18

Figure1Studydesignandflowoftheathletes

19

Figure2Basicexercisesofthe‘Strengthenyourankle’proprioceptivetrainingprogram.

Baselinemeasurement

The online baseline questionnaire gathers information of each athlete on demographic

variables, physical characteristics, sports & injury history, use of preventive measures,

knowledge on injury prevention, severity of the current ankle sprain and subsequent

treatmentand/orrehabilitation.

Follow-upmeasurement

Afterthe8-weektrainingprogram,athleteswillreceiveanonlinefollow-upquestionnaire

to measure residual complaints of the initial ankle sprain and attitude towards the

prescribedexercises.Bothpainandfeelingofgivingwaywillbescoredonfive-pointLikert

scaleforaseriesofquestions.

20

Recurrent injuryincidenceandcostof injuryoutcomeswillbemeasuredoncea

monthforatotalperiodof12months.Thefollow-upmeasurementswillgatherinformation

foreachathleteonanklesprainssustainedduringtheprecedingmonth,includingdetails

andmechanismsofthissprainandabsencefromsportsduetotheanklesprainrecurrence

as ameasure of recurrence severity. Finally, these online follow-upquestionnaireswill

measureresidualcomplaintsoftheinitialanklesprain.Bothpainandfeelingofgivingway

willbescoredonfive-pointLikertscaleforaseriesofquestions,e.g.doyoufeelpainwhen

beingactive,doyoufeelpainwhengettingoutofbedinthemorning,doyoufeelyourankle

givingwaywhenwalkingacross the street, etc. At the last follow-upmeasurement (12

months)residualcomplaintsoftheinitialanklesprainwillbemeasuredagaininallathletes.

Compliance

Compliance (primary outcome)measurementswill commence after randomisation (i.e.

aftertreatmentandatthestartoftheallocatedintervention)andwilltakeplaceweeklyfor

thedurationoftheprogram(8weeks).Thesemeasurementswillgatherinformationfor

eachathleteonthenumberandsetsofexecutedexercises.Inaddition,onlinequestionswill

beaskedregardingtheclarityoftheinstructionsprovided,difficultyoftheexercisesand

recurrenceofananklesprain.

Costdiary

In order to evaluate the cost-effectiveness of the allocated interventions, athleteswho

sustainananklesprain recurrencewillbecontactedbyphone toobtaininformationon

costs associated with treatment. Based on this information direct and indirect costs

resulting from the sustained ankle sprain recurrence will be calculated for use in an

economic evaluation. The economic evaluation will be performed from a societal

perspective.

Cost-effectivenessevaluation

Costs of the allocated intervention will include costs that are directly related to the

implementation of the allocated intervention program. These costs include thewritten

information materials, the development and maintenance of the application, and the

balanceboards.Inadditiontothecostoftheinterventionitself,directhealthcarecostswill

beincluded,i.e.costsofcarebyageneralpractitioner,physiotherapist,massagetherapist,

alternative therapist, sports physician or medical specialist (e.g., orthopaedic surgeon,

generalsurgeon);hospitalcare,useofdrugs(e.g.acetaminophen,ibuprofen)andtheuseof

medicaldevices(e.g.,crutches,tape,braces).Thecostsofdrugswillbeestimatedonthe

basisofpricesrecommendedbytheRoyalDutchSocietyofPharmacy(19).Also,indirect

costsresultingfromalossofproductionduetoabsenteeismfrompaidorunpaidworkwill

beincluded.Indirectcostsforabsenteeismfrompaidworkarecalculatedusingthefriction

costapproachof4months,basedonthemeanageandsexspecific incomeoftheDutch

21

population.Indirectcostsforproductivitylossofunpaidwork,suchasstudyandhousehold

work,costsareestimatedatashadowpriceof€8.30anhour(20).

Samplesize

Samplesizecalculationsarebasedupontheprimaryoutcomemeasurecompliance,andare

baseduponpreviouslyestablishedcomplianceratestothesameprogramwhenadvocated

throughwrittenmaterials[12].Fullcomplianceratesinthewrittenmaterials’groupare

expected tobearound25%.Adoublingof this rate to at least50% is considered tobe

clinicallyrelevant.Baseduponabetaof0.90andanalphaof0.05atotalof158athletesis

requireddividedacrossbothstudygroups.Inourexperiencefrompreviouscomparable

studiesthedropoutrateduringa12monthsfollow-upisabout20%.Thiswouldmeanthat

asampleof190athletesisneededpergroup.

Recruitmentofstudypopulation

Physical therapy and physician practices will aid in the recruitment of athletes.

Participatingpracticeswillbe instructedon theaim,backgroundandproceduresof the

study.Athletestreatedforananklesprainatparticipatingpracticeswillbeinformedofthe

study by their caregiver. Athletes willing to participate, will then be contacted by the

researchteambyphoneafterwhichtheywillenrolinthestudy.

Athleteswill also be recruited through the Internet.Callswill be placed on the

websites of associations of sports with a relatively high ankle sprain rate (volleyball,

handball,basketball,korfball,soccerandathletics),websitesoforganisationsparticipating

in this studyandonsports-relatedwebsites (e.g.www.meetingpoint.nl,www.runinfo.nl,

www.volleybalforum.nl,etc.).Wherepossible,existingmailing listsof sportassociations

willbeusedtocontactpotentialathletesdirectly.Inaddition,electronicnewsletterswillbe

usedforactiverecruitmentofathletes.

Thesamerecruitmentstrategyasdescribedabovehasbeenemployedsuccessfully

intwopreviousstudiesonthesametopic[13,14].Inbothstudiesalargersampleofinjured

athleteswassuccessfullyincluded,476and352athletesrespectively.

Oneofthedrawbacksofthismethodofinclusionisthatwehavenocontrolover

thetreatmentthatisbeinggivenorhasbeengivenforthecurrentanklesprain.Although

rulingguidelinesareconsideredusualcare,thisdoesnotnecessarilymeanthatcaregivers

areactuallyfollowingtheseguidelinesbythebook.Inclusionofathletesthroughalimited

numberofcontrolled(para)medicalcaregiverswoulddecreasethisproblem.However,as

wehavelearnedinpreviousstudies,inclusionthroughsuchchannelsisproblematicand

almostalwaysresultsinlowerinclusionratesthanexpected.Evenso,intheproposedstudy

wearelookingforathletestreatedbyavarietyof(para)medicalcaregivers.Meaningthat

intheproposedstudyarelativelylargenumberofdifferentcaregiverswouldneedtobe

found, informedonthestudy,andcontrolledasto theirgiventreatment.Lookingatthe

required number of athletes we believe thiswould prove an undoable and unrealistic

22

undertaking. Moreover, the proposed study is on the effect of secondary preventive

measuresthatarebeingappliedaftertreatmentbythe(para)medicalcaregiver.Whenthe

caregiverwouldperforminclusion,thismeansthatrandomisationneedstotakeplaceat

thelevelofthecaregiver.Thisfurthercomplicatesthestudydesign.

Usualcareasemployedinthecurrentstudy

Forthecurrentstudy,usualcareisdefinedasanycaretheathletemightseekorreceive

afterananklesprain.Wealsodefineself-treatmenttobeusualcareinthecurrentstudy.

Nexttotreatmentbya(para)medicalprofessional60percentofanklesprains-mostly

minor-isself-treatedbytheathlete(5).Consequently,theseathletesdonotreceivethecare

asdescribedinthebelowmentionedrulingguidelines.

Incasetheathletedoesreceive(para)medicalcare,therearetworulingmedical

guidelines for the treatment of ankle sprains in the Netherlands, i.e. the Royal Dutch

PhysiotherapyAssociation (KNGF)guideline (16)and theDutchInstituteforHealthcare

Improvement (CBO) guideline (17). The KNGF guideline, which is the most commonly

employed, aims at optimal functional recovery of the ankle, returning to full sports

participation and preventing recurrent ankle injuries. Rehabilitation consists of three

phases:phase1whichaimstoreducepainandswelling,phase2inwhichloadisgradually

increasedandfunctionality isre-establishedandphase3inwhichnormalaveragedaily

living (ADL) tasks are performed. After full rehabilitation athletes are advised to use

secondarypreventivemeasures.Whereaseliteathletescouldhavetreatmentdurationof

uptotwelveweeks,sixweeksareconsideredsufficientforamateurathletes,accordingto

theKNGFguidelines(16).

Forthepurposeofthecurrentstudywedonotinterfereintheathletes’choiceof

caregiverandthecaregivers’compliancetotherulingguidelines.

Statisticalanalyses

Allanalyseswillbecarriedoutaccordingtotheintention-to-treatprinciple.

Complianceratesbetweengroupswillbecomparedbymeansofamultivariate

linear regression analysis using compliance as a continuous dependent variable. Cox-

regressionanalysiswillbeusedtocompareanklerecurrenceriskbetweentheintervention

andthecontrolgroup.Absencefromsportswillbecomparedbetweenthetwogroupsusing

aMann-Whitneytest,sinceabsencefromsportsduetoaninjuryisnotnormallydistributed.

Forallanalyses,variableswillbecheckedforconfoundingand/oreffect-modificationand

willbeadjustedforaccordingly.

Meandirect,meanindirectandtotalcostswillbeestimatedandcomparedbetween

thetwogroups,bothforthecostsperathleteintheinjuredpopulationandforthecostsper

athlete in the total population. Because costs will not be normally distributed, 95%

confidenceintervalsforthedifferencesinmeancostswillbeobtainedbybias-corrected

andacceleratedbootstrappingwith2000replications.Differencesincostsanddifferences

23

inanklesprainrecurrenceswillbeincludedinacost-effectivenessratio,whichestimates

theincrementalcoststopreventoneanklesprainrecurrence.Confidenceintervalsforthe

cost-effectiveness ratio will be calculated with bootstrapping, using the bias-corrected

percentilemethodwith5000replications.Uncertaintyof this ratiowillbeevaluatedby

presentingacost-effectivenessplaneandsensitivityanalyseswillbeperformedtocheck

therobustnessoftheresults.Anacceptabilitycurvewillalsobepresented.

Impactofresults

Theresultsofthisstudycanpossiblyleadtoachangeinthetreatmentofanklesprains.

Positiveresultscanofferextendedpossibilitiesforimplementationoftheinterventionin

usualcare.Positivestudyresultscanalsoleadtochangesinthepracticalguidelinesonthe

treatmentofanklesprains.Furthermore, if the ‘Strengthenyourankle’Appindeeddoes

increaseinterventionuptakethiswillprovidethenecessaryvalidationtofurtherdevelop

and enhance this promising role of new media in the implementation of preventive

measuresandinterventions.

Resultsofthisstudywillbecomeavailablein2014.

Competinginterests

Theauthorsdeclarenocompetinginterest.

Authors’contributions

EV(e.verhagen@vumc.nl)conceivedtheresearchidea.MVR(m.vanreijen@vumc.nl)and

EVhavewrittentheprotocol.MVRwillscreenandincludepatients,performdataanalysis

and be the main author of articles on the primary aim of the study. IV

(i.vriend@veiligheid.nl), WVM (w.vanmechelen@vumc.nl) and VZ (v.zuidema@vumc.nl)

contributed to ideas in theprotocol.All authorshavereadandcommentedon thedraft

versionandapprovedthefinalversionofthemanuscript.

ACKNOWLEDGEMENTS

This study was funded by the Netherlands organisation for health research and

development(ZonMW),grantnumber525001003.

24

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2. FernandezWG,YardEE,ComstockRD(2007)Epidemiologyoflowerextremity

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5. VerhagenEALM,VanTulderM,VanderBeekAJ,etal.(2005)AnEconomical

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9. VerhagenEALM,BayK(2010).Optimisinganklesprainprevention:acriticalreview

andpracticalappraisaloftheliterature.BrJSportsMed.44(15):1082–1088.

10. HupperetsM,VerhagenEALM,HeymansM,etal.(2010)Potentialsavingsofa

programtopreventanklesprainrecurrence:economicevaluationofarandomized

controlledtrial.AmJSportsMed38(11):2194–2200.

11. HupperetsM,VerhagenEALM,VanMechelenW(2009)Effectofunsupervisedhome

basedproprioceptivetrainingonrecurrencesofanklesprain:randomisedcontrolledtrial.

BMJJul9;339:b2684.

12. VerhagenEALM,HupperetsM,FinchC,MechelenWV(2011)Theimpactof

adherenceonsportsinjurypreventioneffectestimatesinrandomisedcontrolledtrials:

lookingbeyondtheCONSORTstatement.JSciMedSportJul.;14(4):287–92.

13. JanssenK,MechelenWV,VerhagenEALM(2011).Anklesbackinrandomized

controlledtrial(ABrCt):bracesversusneuromuscularexercisesforthesecondary

preventionofanklesprains.Designofarandomisedcontrolledtrial.BMCMusculoskelet

Disord.12:210.

25

14. HupperetsM,VerhagenEALM,MechelenWV(2008)The2BFitstudy:isan

unsupervisedproprioceptivebalanceboardtrainingprogram,giveninadditiontousual

care,effectiveinpreventinganklesprainrecurrences?Designofarandomizedcontrolled

trial.BMCMusculoskeletDisord.9:71.

15. DeBieRA,HendriksHJM,LenssenAF,vanMoorselSR,OprausKWF,Remkes

WFA,SwinkelsRAHM(1998)KNGFRichtlijn:Acuutenkelletsel.NederlandsTijdschrift

voorFysiotherapie108(supplement)

16. Consensusdiagnostiekenbehandelingvanhetacuteenkelletsel,CBO1999

17. PressreleaseIDC:Applecedesmarketshareinsmartphoneoperatingsystem

marketasAndroidsurgesandWindowsphonegains,accordingtoIDC.August7,2013.

Availableat:http://www.idc.com/getdoc.jsp?containerId=prUS24257413.VisitedAugust

12,2013

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specialist,exclusiefpsychiaters.Bijlagebijtariefbeschikkingnummer5600-1900-97.

Utrecht:CTG,1996.

19. OostenbrinkJB,BouwmansCAM,KoopmanschapMA,RuttenFF.Handleidingvoor

kostenonderzoek.Methodenenstandaardkostprijzenvooreconomischeevaluatiesinde

gezondheidszorg.Geactualiseerdeversie2004.Collegevoorzorgverzekeringen.

26

27

CHAPTER3 CompliancewithSportInjuryPreventionInterventionsinRandomisedControlledTrials:

ASystematicReview

MiriamvanReijen

IngridVriend

WillemvanMechelen

CarolineFinch

EvertVerhagen

SportsMedicine2016Digitalobjectidentifier(doi):doi:10.1007/s40279-016-0470-8

three.

28

ABSTRACT

INTRODUCTION: Sport injury prevention studies vary in theway compliance with aninterventionisdefined,measuredandadjustedfor.

OBJECTIVE:To assess the extent bywhich sport injury preventionRCTs have defined,measuredandadjustedresultsforcompliancewithaninjurypreventionintervention.

METHODS:AnelectronicsearchwasperformedinMEDLINE,PubMed,theCochraneCenterof Controlled Trials, CINAHL, PEDro and SPORTDiscus. English RCTs, quasi-RCTs and

cluster-RCTwere considered eligible. Trials that involved physically active individuals,

examinedtheeffectsofaninterventionaimedatthepreventionofsportorphysicalactivity

relatedinjurieswereincluded.

RESULTS:Atotalof110studieswereincluded.Ofallstudies,71.6%mentionedcomplianceorarelatedterm,68.8%provideddetailsoncompliancemeasurement,and51.4%provided

compliancedata.Only19.3%analysedtheeffectofcomplianceratesonstudyoutcomes.

Whilestudiesusedheterogeneousmethods,pooledeffectscouldnotbepresented.

CONCLUSIONS: Studies that account for compliance demonstrated that compliancesignificantaffectsstudyoutcomes.Thewaycomplianceisdealtwithinpreventionsstudies

issubjecttoalargedegreeofheterogeneity.Validandreliabletoolstomeasureandreport

complianceareneededandshouldbematchedtoauniformdefinitionofcompliance.

KEYPOINTS:• Compliancetoinjurypreventioninterventionscansignificantlyaffectstudyoutcomes• Thereisconsiderableheterogeneityinthewaythatsportsinjurypreventionstudieshavemeasured,definedandreportedcompliance.Moreuniformityisneededinfuturestudiestobetterprogresssportsinjuryprevention.

29

INTRODUCTION

It iswidely recognized thatparticipation in regular sportsandphysicalactivityhas the

potentialtoimprovehealth[1].However,involvementinsuchactivitiesalsoentailsarisk

ofsustaininganinjury.Serioussportinjuriesthattakeaconsiderabletimetohealcanforce

thoseinvolvednotonlytowithdrawfromtheactivity,butalsotoseekmedicalcare,invest

in medication and assisting materials – such as tape, braces, crutches. They can even

preventsomeonefromcontinuingworkorstudyactivities.Asaresult,injuriesleadnotonly

toanindividualburden,butalsotosubstantialsocietaldirectandindirectcost[2].

Numerousstudieshavebeenperformedtoevaluatetheefficacyofinterventionstoprevent

sportinjuriesortoreducetheriskofrecurrentinjury[3].Althoughavarietyofefficacious

preventiveinterventionshavebeenproposed,implementationoftheseinterventionsfaces

thechallengeofpersuadingparticipantstofollowinstructionsasprescribed.Establishing

theeffectiveness ofany injury prevention intervention, requires knowledgeaboutwhat

percentage of the targeted population exactly complied with the prescribed protocol.

Especially in an intention-to-treat approach, insights into the compliance to the

interventionprovidesvaluable,andarguably,necessaryinformationtojudgetheefficacyof

anintervention[4].

When one incorrectly assumes that the entire study population has compliedwith the

intervention protocol, the preventive effect of any intervention can be either over- or

underestimated. Unfortunately, many different definitions of compliance have been

reported in the sports medicine literature [3]. Both the constructs of compliance and

adherencehavebeenusedinterchangeablytodescribethecompleteandcorrectfollowing

ofaprescribedintervention.Nonetheless,thetwotermsarenotsynonymous.Compliance

refers to participant obedience in a study where a clinician/researcher prescribes the

intervention,withlittletonorightofconsultationonbehalfoftheparticipant.Itcanthus

bedefinedas“theathletes’correctfollowingoftheprescribedintervention”.[4]Adherence

implicatesamorecollaborativeenvironmentinwhichaclinician/researcherandastudy

participant cooperate to develop an intervention that fits with the participants’

opportunitiesandrestraints[5,6].Research,ideallyperformedinamoreorlesscontrolled

setting,thereforeimplicitlyfocusesoncompliance,ratherthanonadherence.

In addition to using correct definitions, the operationalization of compliance requires

attention. A comprehensive assessment of study resultswill only be possible if there is

thoroughinsightintothewaycompliancehasbeendefined,measuredandadjustedfor.If

thereisno,orincomplete,informationavailableontheextenttowhichparticipantshave

compliedwiththeintervention,itwillremainunclearastowhethertheinterventionhas

beentrulyefficaciousornot.Therefore,itisimportantthatresearchers,whoaimtopresent

studiesofhighqualitywithalowriskofbias,acknowledgetheimportanceofcompliance,

andmeasureandreportuponcomplianceanditseffectsonstudyoutcomes.

Anumberofstudyreportingguidelines,suchastheSTROBEstatementandtheCONSORT

statement,recognizetheimportanceofcomplianceandincludespecificitemsonthetopic

intheirguidelines[7-9].

The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE)

30

statement addresses cohort, case-control and cross-sectional studies: CONsolidatedStandardsOfReportingTrials(CONSORT)–specificallyaddressesthequalityofreportsofrandomizedcontrolledtrials(RCTs).

Until 2010, the CONSORT statement advocated the use of iIntention-tTo-tTreat (ITT)

analysisforrandomizedcontrolledtrials.Intention-to-treatanalysisdoesnotincludethe

measurementofcompliancebutassumesfulladherencetotheprescribedintervention[4].

However, asmentioned in the CONSORT statement, strict ITT analysis ‘is often hard to

achievefortwomainreasons:missingoutcomesforsomeparticipantsandnon-adherence

totheprotocol.Therefore,since2010,theCONSORTStatementhasreplacedthemention

ofITTbytherequirementof‘moreinformationonretainingparticipantsintheiroriginal

assignedgroups’[7].AsanalternativetoanITTanalysis,ithasbeensuggestedthatper-

protocol-analysis (PPA)– sometimesreferred toas ‘modified intention-to-treat’- canbe

used[4].Inthisapproach,theanalysisisperformedonlyonthoseparticipantswhohave

fullycompliedwiththeprogram.APPAcanprovideameasurementofefficacyinthat it

gives the result of a prescribedprogram that is implementedexactly as the researcher

originally has developed it. It is currently unclear towhat extent RCTs on sport injury

preventionhaveincludedtheguidelinesprovidedbytheCONSORTStatementandtowhat

extentcompliancemeasureshavebeenaddressed.Thissystematicreviewthereforeaims

toassess theextent towhichsport injurypreventionRCTshavedefined,measuredand

adjustedtheirresultsforcompliancewiththetrialledintervention/s.

METHODS

Researchquestions

This review answers the following questions to provide a detailed analysis on how

compliancehasbeenreportedinsportinjurypreventionstudies:

1) Howandhowoftenwascompliancedefined?

2) Whendefined,howwascompliancemeasured?

3) Whendefinedandmeasured,howwastheoutcomeadjustedforcomplianceintheanalysis?

Electronicsearches

Sevenelectronicdatabasesweresystematicallysearchedforpeer-reviewedpublicationson

sport injury prevention interventions: PubMed (to October 2014), MEDLINE (1966 to

October 2014), SPORTDiscus (1949 toOctober 2014), the CochraneCentral Register of

Controlled Trials (to October 2014), CINAHL – Cumulative Index toNursing and Allied

HealthLiterature(1982toOctober2014),PEDro–ThePhysiotherapyEvidenceDatabase

(toOctober2014)andWebofScience(toOctober2014).Astandardizedsearchstrategy,

31

basedonawordstring,includingrelevantsportsinjurytermsandstudydesigns,wasused.

Thefollowingkeywords,andvariouscombinationsofthosewords,wereusedinthesearch:

sport injury/ies, athletic injury/ies, prevention, preventive, preventi*, randomiz/s/ed,

randomiz/s/edcontrolledtrial.Referencelistsandrelatedcitationsofincludedstudiesand

relevantsystematicreviewswerealsohandsearchedforapplicablepublications.

Inclusioncriteria

OnlyRCTs,quasi-RCTsandcluster-RCTwereconsideredeligibleforinclusion.Thereason

for including only (cluster and/or quasi)RCTs is that these studies maximize internal

validitywhichcanbeseenasaprerequisiteforexternalvalidity.Trialswereincludedthat

involvedphysicallyactiveindividualsofeithersexandofallages.Tobeselected,studies

hadtoexaminetheeffectsofaninterventionaimedatthepreventionofsportorphysical

activityrelatedinjuries.Theprimaryoutcomeofthestudieshadtobeameasureofsports

or physicalactivity related injury (i.e. injury rate, time to first injury, or the number of

injuredindividuals).OnlyEnglishlanguagepublicationswereconsidered.

Exclusioncriteria

Studiesthatdidnotassesspreventionofsportsinjury,thatwerenotaRCT,quasi-RCTor

cluster-RCT or did not involve a physically active population were excluded from this

review.

Definitions

Compliance in this reviewwasdefinedas ”theathletes’ correct followingofaprescribedintervention”[4].Itisacknowledgedthatanumberoftermshavebeenusedinthescientificliterature, referring to comparable constructs. As such, for the purpose of this current

review,we considered all text referrals to participants’ following of an intervention as

compliance. Other examples of phrases equivalent to compliance commonly used in

publicationsare‘use’,‘cooperation’and‘adoption’[4].Inthisreview,allstudiesincluded

werescrutinizedthoroughlytoidentifythespecificform/phraseusedbytheauthors.This

ensuredthatallaccountsofcompliancewereincluded.

Methodologicalquality

Potentiallyeligiblestudieswereinitiallyscreenedbytitleandabstractbytheprimary

author.Wheneligibilitywasunclear,full-textarticleswereretrieved.Inordertoassess

themethodologicalqualityandriskofbias,allincludedstudieswereassessedbasedon10

outof12criteriaasrecommendedbyFurlanetal.[10].Theseincludedthemethodof

randomization,concealedallocation,blindingofparticipants,blindingofcareproviders,

blindingofoutcomeassessors,dropoutrate,analysisaccordingtoallocatedgroup,

baselinesimilarityofthegroups,complianceandtimingofoutcomeassessment.Thiswas

donetoassessifthereweredifferencesintheriskofbiasbetweenstudiesthatdidanddid

32

notreportcompliance.Itispossiblethatstudiesthatdidnotreportcompliance,alsofailed

toreportotherimportantmethodologicalanddesignproperties.Twocriteriawere

omittedfromFurlanetal.[10]:thereportingwithoutselectiveoutcomeandavoidanceof

co-interventionsasthesecriteriawherenotconsideredasdistinctiveforriskofbias

betweentheincludedstudies.

Eachcriterionwasscoredas‘yes’,‘unclear’or‘no’.Furlanetal.[10]definedstudieswith

morethansixpoints(yes=1point)ashaving‘lowriskofbias’.Astwocriteriawereomitted,

theoriginalscoringwasadjusted.Hence,morethanfivepointswasconsideredasthecut-

offfor‘lowriskofbias’.

Tofamiliarizetheauthorswiththeriskofbiasassessment,threereviewers(MvR,IVand

EV) scored ten studies that were randomly selected from all studies. Examining the

disagreement in the assessment of these 10 studies allowed the reviewers to identify

possible incongruities in scoring. Thereafter, the total number of studies (n=110) was

randomly divided in two equal size sets (n=55) and two reviewers (MvR and IV) both

independentlyassessedriskofbiasforoneset.Forthecodingreliabilityassessment,from

eachofthesets,19studieswererandomlyselected.Bothreviewersscoredthese38studies.

Itwasagreedthatiftheagreement(kappa)scoreforthese38studieswas>0.9,agreement

wasacceptableandtherewasnoneedforthereviewerstoscoreallstudiesseparately.Out

ofthe380itemsthatwerescoredtwice,therewasagreementon370items.Thisresulted

inanagreement(kappa)scoreof0.95.Basedonthishighlevelofagreement,itwasthus

decided that the remainder of themanuscripts did not needed to be assessed by both

reviewers.

Dataextraction

Onereviewer(MvR)scrutinizedtheincludedstudiesforalltermsreferringtocompliance.

Thereafter, for thestudies thatmentionedcompliance,detailsabout thedefinitions, the

methodsofcompliancemeasurementsand thecorrespondingoutcomeswereextracted.

Finally,allstudieswereexaminedforadjustmentofthemainoutcomeintheiranalysesby

compliancerates.

RESULTS

Searchresults

Thesearchstrategyinitiallyyielded1,902studies,ofwhich,atotalof289full-textarticles

wereretainedafterinitialscreeningforeligibility.Atotalof180studieswerethenexcluded

(Figure1),resultingin109studiesincludedinthisreview.Primaryreasonsforexclusion

werethatstudiesdidnotinvolveanRCTordidnotuseinjuryasanoutcomemeasure.For

five studies, full-text articles could not be retrieved [11-15]. Electronic Supplementary

Material Appendix S1 provides an overviewof the studies included in the final review.

Figure2describestheincludedstudiesintermsoftheirmentioningof,measurementof

and/oradjustmentforcompliance.

33

Fig.1:Literaturesearchflowchart

34

Fig.2:Annualtrendsincompliancereporting

Riskofbiasscores

The109includedstudiesscoredanaverageof4.1±1.8yesratings(outof10),2.8±1.3no

ratingsand3.3±1.8unknown(DK’s)ontheriskofbiasassessmentinstrument.Itcanthus

beconcludedthatingeneral,theincludedstudiesdemonstratedafairlyhigh‘riskofbias’.

The21studiesthatexplicitlyadjustedforcomplianceratesintheirstudyoutcomes–and

hencehadprovidedmostdetailsoncomplianceintheirreport-scoredanaverageof4.7±

1.6ontheriskofbiasassessment,comparedtoaveragescoresof3.9±1.8forthe88studies

that did not account for compliance. This suggests that the studies that accounted for

compliancehadaslightlyhighermethodologicalqualitythandidthosestudieswithoutsuch

adjustment. Electronic Supplementary Material Appendix S1, section I provides an

overviewoftheriskofbiasscoreofeachoftheincludedstudies.

10

23

6

11

21

33

24

Total number of studiesCompliance mentionedCompliance definedCompliance measuredCompliance adjusted for in analyses

Num

ber

of st

udie

s

0

5

10

15

20

25

30

35

Year of publication1970 - 1975 1976 - 1980 1981 - 1985 1986 - 1990 1991 - 1995 1996 - 2000 2001 - 2005 2006 - 2010 2011 - 2014

35

Compliance

Termsusedforcompliance

Ofallstudies,78(71.6%)mentionedcomplianceorarelatedterm.Mostcommonwasthe

use of the term ‘compliance’ (n=57, 52.3%). Other terms used were ‘use’ (n=8) and

‘adherence’(n=6)‘attendance’(n=2),‘cooperation’(n=1)and‘participation’(n=1).Some

studies usedmultiple terms by switching between ‘compliance’ and ‘adherence’ (n=2),

‘compliance’and‘exposure’(n=1)or‘compliance’and‘internaldrop-out’(n=1).Electronic

SupplementaryMaterialAppendixS1,sectionIIprovidesanoverviewofthetermsusedin

theincludedstudies.

Measurementsofcompliance

The majority of the 78 studies that mentioned compliance, 75 (68.8% of all studies

included) provided details on how they measured compliance. Compliance rates were

recorded through a diversity of methods. Studies that concerned supervised exercises

derivedcompliancerates fromawrittenoronline reportbya supervisor,e.g.a trainer,

coachordesignatedteammember(n=15):[16-30].Home-basedorindividualexercises

studiesmadeuseofawrittenoronlineself-report(n=12):[31-42].Instudiesrelatingto

theuseofprotectiveequipment(orthoses,wristprotectorsetc.)orsupplements,thisuse

was recorded by either the participant (n=4: [43-46]or a supervisor (n=5): [47-51]. In

fifteenstudies [47,52-65] thewearing/usageofprotectiveequipmentwasonlychecked

visually.Inthreestudies[52,54,62],alackofcompliancewithwearing/usageofmaterial

resultedinprohibitiontoparticipate;thesestudiesthereforesuggested100%compliance

forpeoplewhoremainedinthestudy.Forexample,theparticipantswhoweredesignated

towearahelmetduringfootballwerevisuallycheckedbeforetheyenteredthefield;non-

compliancewearingthehelmetresultedintheprohibitiontoplay[52].

In twenty-four studies, researchers verified the reported compliance rates bymultiple

methods.These includedcombiningself-reportwith thereportofa supervisor [66-70],

combiningareportofasupervisorwithrandomvisits[5,71-78],combiningareportofa

supervisorwithphonecallsandvisits[79-81],combiningself-reportwithrandomvisits

[82],combiningareportofasupervisorwithphonecallsandemails[83]orcombiningself-

reportwithphonecalls[71].

Thirty-onestudiesincludedinthisreviewwereconductedinamilitarysetting.Althoughit

mightbeexpectedthatamilitarysettingwouldmakeiteasiertoreportoncompliance–

withmanysupervisedactivitiesandahighlycompliantenvironment–thesestudiesdidnot

providemoredetailsoncompliancethanotherstudies.Slightlylessthanhalfofthemilitary

studies(n=14)provideddetailsoncompliancemeasurements.In8ofthese14studies,it

wasreportedthattheparticipantswerevisuallycheckedorsupervisedwhilecarryingout

theintervention.Twoofthoseeightstudiesprovidednofurtherdetailsoncompliancerates

[53,54], two studiesexcludedparticipants from theanalysiswhen they did not comply

[55,61] and the other four studies reported compliance rates between 57% and 100%

[47,56,57,60]. Electronic Supplementary Material Appendix S1, section III provides an

overviewofwaysinwhichstudieshavereportedcompliancerates.

36

Compliancedataandadjustmentsforcompliancerates

Ofthe75studiesthatprovidedinformationoncompliancemeasurement,only56studies

(51.4%ofall includedstudies)providedcompliancedata.Thesedatawerepresentedin

heterogeneous ways. Nine studies [5,16,67,71,74,79,81,84,85]created subclasses of

participants in which high, intermediate and low rates of compliance were defined.

However, the (arbitrary) cut-off percentage that was considered for high versus low

compliancevariedconsiderablybetweenstudies.

Forexample,inacluster-RCTontheFIFA11+injurypreventionprogram,low,middleand

highcomplianceweredefinedrespectivelyasperforming<24.7%,24.8-48.1%or>48.2%

ofallexercises[84].Thisresultedinthecategorizationof18%teamsinthelowcompliance

category,41%teamswithinthemoderatecompliancecategoryand41%teamsinthehigh

category. In another neuromuscular training intervention cluster-RCT, high compliance

wasdefinedascarryingoutthree(outof3)sessionsinafirstintensiveinterventionperiod,

twosessionsinthesecondinterventionperiodandonesessioninthethird/maintenance

period[16].Inthisstudy,36%oftheteamswereconsideredashighlycompliant,43%of

theteamsasirregularlycompliantand21%oftheteamsashavinginterruptedcompliance.

Otherstudieschoose to report compliance foreachplayer [5,73,75,79,81,84,86], for the

teamasawhole[17,19,20,72,74,75,78,79,81,87],oraseasonalcompliancerate[20,79].In

addition, some studies combined compliance rates of the intervention and the control

group, which were presented as one overall compliance rate [21,22,57,70,82,88,89].

ElectronicSupplementaryMaterialAppendixS1, section IVprovidesanoverviewof the

studiesthatreportedcompliancedata.

Inaddition toprovidingcompliancerates,amere21studies[5,16,17,20,31,32,43,58,67,

71,74,76,77,79,83-85,88,90,91], (19.3% of all included studies) analysed the effect of

differentcomplianceratesonstudyoutcomes.Asthestudiesusedheterogeneousmethods

to report theseanalyses, it is impossible toprovideapooledeffectof compliancerates.

Therefore,Table1presentsthedetailsoftheeffectofmeasuredcomplianceratesontheir

studyoutcomeinthese21studies.

Study Intervention Population(nintervention/ncontrol;%male)

Reportedcompliancerate(%)ingroupsbeingcompared

Analysisoftheeffectofcomplianceonstudyoutcome

Cobbetal.

[43]2007

Oral

contraceptives

Youngdistancerunners

(69/81,0%)

74.5%wereseenascompliant.Compliance

wasdefinedasusingmorethan6monthsof

oralcontraceptives.

Compliantwomenweresignificantlyprotectedagainst

fractures(by77%),thoughthisestimatewas

weakenedwhenweexcludedfracturesthatoccurred

earlyinthetrial(58%reductioninrisk,P=0.20).The

researchersdomentionthatthisfindingcouldhave

beentheresultofchanceorbiasasitwasfoundthat

womenwhoswitchedfromthecontrolgrouptooral

contraceptiveusewerelesslikelytohaveahistoryof

stressfracturesbeforejoiningthestudy.

Emeryetal.

[71]2005

Home-based

balancetraining

PEstudents

(66/61,50%)

Noreportofspecificcompliancerates Effectofcomplianceonstaticbutnotdynamicbalance.

Compliancewithbalancetrainingsessionshadaneffect

onthechangeinstaticbalance:theobservedchange

amongstudentsintheinterventiongroupwho

reportedfewerthan18sessionsover6weekswas

holdingtheirbalancefor6.1seconds(95%CI–8.4to

20.7),ascomparedwith25.8seconds(95%CI16.4to

35.1)amongthosewhoreported18ormoresessions.

Compliancedidnothaveasignificanteffectonchange

indynamicbalance.

Engebretsen

etal.[31]

2008

Exerciseprogram Soccerplayers

(315/193,100%)

Compliancewasdefinedascompleting

morethan30sessions:29.2%forknee

exercises,21.1%forhamstringand19.4%

forgroinexercises

Nodifferencewasdetectedintheriskofkneeinjury

betweenplayersinthehighriskinterventiongroup

whowerecompliantwiththekneeprogram(0.2[95%

CI,–0.2to0.7]injuriesper1000hours)andthehigh

riskplayersinthehighriskcontrolgroup(0.5[95%CI,

0.2-0.9]injuriesper1000hours;RR=0.46;95%CI,

0.1-3.7).Inthesameway,nodifferencewasobserved

intheincidenceofhamstring(RR=0.94;95%CI,0.3-

3.2)andgroininjuries(RR=1.6;95%CI,0.5-5.6)

betweenplayersinthehighinterventiongroupwho

werecompliantwiththerespectivetrainingprograms

andthehighcontrolgroup.

Gabbeetal.

[90]2006

Eccentric

hamstring

exercises

AmateurAustralian

Footballplayers

(114/106,100%)

46.8%participatedinmorethan2sessions Significantdifferenceduetocompliance.Whenonly

controlandinterventiongroupplayerswho

participatedinatleastthefirsttwosessionswere

analyzed,atrendtowardsaprotectiveeffectforthe

interventiongroupwasnoticed(RR0.3,95%CI:0.1,

1.4;p=0.098).Only4%ofthecompliantgroupsustainedaninjurycomparedto13.2%inthecontrol

group(nop-valuespecified).

Hagglundet

al.[74]

2013

Neuromuscular

trainingprogram

Soccerplayers

(2471/2085,0%)

79%teamcompliance.Teamcompliance

wasdefinedascompletingasupervised

neuromusculartraining.

Teamswiththehighestlevelofcompliance(89%)had

88%lowerriskofre-injuryratecomparedtocontrol

andlowcompliance(63%)teams.Lowandcontrol

werenotsignificantlydifferent.

Hupperets

etal.[32]

2009

Proprioceptive

training

Athleteswithanankle

sprain(256/266,52.4%)

Fullycompliant:23%,partiallycompliant

29%,non-compliant35%,unknown13%.A

definitionofcompliancewasnotprovided.

Althoughasignificantreductioninriskofinjurywas

foundinallgroups,theresearcherssuggestthata

highercompliancemighthaveresultedinfewer

recurrentinjuries.

Kianietal.

[20]2010

Exerciseprogram

+education

Soccerplayers

(777/729,0%)

6%ofplayerswere50%compliant,75%

were75%compliantand18%were100%

compliant.Adefinitionofcompliancewas

notprovided.

Includingonlycompliantteams:therewasanon-

significantdifferentrateratiointheinterventiongroup

comparedwithcontrolsforallinjuries(0.17(95%CI,

0.02-0.75))andfornoncontactinjury0.11(0.95%CI,

0.02-0.77).

1Inthisstudyparticipantswereassignedtothreedifferentstudygroups:thecontrolgroup,thestandardheadgeargroupandthemodifiedheadgeargroup.

Larsenetal.

[68]2002

Custommade

shoeorthoses

Conscripts

(77/69,99.3%)

88.3%overall(controlandintervention).A

definitionofcompliancewasnotprovided.

ITTanalysisgaveanRRof0.7(0.5-1.1)andPPA

analysisanRRof0.3(0.1-0.7)

Longoetal.

[83]2012

FIFA11+warm-

up

Basketballplayers

(80/41,100%)

100%compliance.Adefinitionof

compliancewasnotprovided.

Intheinterventiongroup,IID'swerelowerthanthose

inthecontrolgroupforoverallinjuries(0.95vs2.16;P=.0004),traininginjuries(0.14vs0.76;P=.007),lowerextremityinjuries(0.68vs1.4;P=.022),acuteinjuries(0.61vs1.91;P=.0001),andsevereinjuries(0vs0.51;P=.004).Theinterventiongroupalsohadlowerinjuryratesfortrunk(0.07vs0.51;P=.013),leg(0vs0.38;P=.007),andhipandgroin(0vs0.25;P=.023)comparedwiththecontrolgroup.Differencesin

matchinjuries,kneeinjuries,ankleinjuries,and

overuseinjuriesbetween2groupswerenotsignificant.

Macholdet

al.[58]

2002

Wristprotectors Students

(342/379,60%)

96.5%Adefinitionofcompliancewasnot

provided.

Theriskofseverewristinjurydecreasedbyafactor

0.13usingtheprotector.

McIntoshet

al.2009

[76]

Paddedheadgear Rugbyplayers

(1493/1128/1474/100%)1

Standard:48.9%,modified:40.1%.

Compliancewasdefinedaswearing

headgear.

Headinjuryandconcussionratesbasedonheadgear-

wearingcompliancewerenotsignificantlydifferent.

Myklebust

etal.[17]

2007

Neuromuscular

training

Handballplayers

(850/942,0%)

1stseason26%&42%elite,2ndseason29%

&50%elite,youth87%.Compliancewas

definedasconductingaminimumof15ACL

injurypreventionsessionsduringthe5-7

weekperiodwithmorethan75%ofthe

athletesparticipating.

Therewasdownwardtrendinthenumberofinjuries

duringthestudyperiod,ascomplianceseemedto

improve.Duetoacrossovereffectof22%,bothteams,

showedasignificantlowerrateofinjuries.

Pasanenet

al.[16]

2008

Neuromuscular

training

Floorballplayers

(256/201,0%)

74%Highcompliancewasdefinedas

carryingoutatleastthreetrainingsaweek

duringthefirstintensiveperiod,atleast

twiceaweekduringthesecondintensive

period,andatleastonceaweekduringthe

maintenanceweeks.

Interventionteamswithhighcompliancetothe

neuromusculartraininghadalowerriskofinjurythan

thecontrolgroup:theincidencerateratiobetweenthe

highcompliancegroupandcontrolgroupfornon-

contactleginjurywas0.19(95%confidenceinterval

0.06to0.64,P=0.007),fornon-contactankleligament

injury0.19(0.05to0.82,P=0.026),andfornon-contact

kneeligamentinjury0.32(0.04to2.59,P=0.284).

Ronninget

al.[91]

2001

Wristprotectors Snowboarders

(2515/2514,64.2%)

99.5%Adefinitionofcompliancewasnot

provided.

Inthebracedgroup,8wristinjuries(3fracturesand5

sprains)wererecorded,comparedwith29wrist

injuries(2fracturesand27sprains)recordedinthe

controlgroup.Consideringalltypesofinjuries,atotal

of33injuriesoccurredinthebracedgroupand51in

thecontrolgroup.Thisisasignificantdifferencein

favorofthebracedgroup(chi-squaretest:x2=3.9,

p=0.05).

Sodermanet

al.[67]

2000

Balanceboard

training

Soccerplayers

(62/78,0%)

70%.Complianceisdefinedasperforming

morethan70sessions.

Intheinterventiongroup,nosignificantdifferencewas

foundinthenumberoftraumaticinjuriesorinjured

playersbetweenthosewhowerecompliant(n=27)and

thosewhowerenon-compliant(n=35)subgroups.

Soligardet

al.[79]

2008

FIFA11+warm-

up

Footballplayers

(1055/1220,0%)

77%(team)and57.9%(player),high

compliance(33-95sessions),intermediate

compliance(15-32sessions),low

compliance(0-14sessions)

Theriskofinjurywas35%lowerinintervention

playersinthethirdwiththehighestcompliance2.6

(2.0.to3.2)injuries/1000playerhours,comparedwith

playersintheintermediatethird4.0(3.0to5.0)

injuries/1000playerhours(rateratio0.65,0.44to

0.94,P=0.02).The32%reductioninriskofinjury

comparedwiththethirdwiththelowestcompliance

(3.7(2.2to5.3)injuries/1000playerhoursdidnot

reachsignificance(rateratio0.68,0.41to1.12,

P=0.13).

Soligardet

al.[81]

2010

FIFA11+warm-

up

Footballplayers

(1055/1220,0%)

77%(team)and57.9%(player),high

compliance(33-95sessions),intermediate

compliance(15-32sessions),low

compliance(0-14sessions)

Theriskofinjurywas35%lowerinintervention

playersinthethirdwiththehighestcompliance2.6

(2.0to3.2)injuries/1000playerhours,comparedwith

playersintheintermediatethird4.0(3.0to5.0)

injuries/1000playerhours(rateratio0.65,0.44to

0.94,P=0.02).The32%reductioninriskofinjury

comparedwiththethirdwiththelowestcompliance

(3.7(2.2to5.3)injuries/1000playerhoursdidnot

reachsignificance(rateratio0.68,0.41to1.12,

P=0.13).Furthermore,theriskofanacuteinjurywas

39%(p=0.008)lowerforplayersinthetertilewiththe

highestcompliancecomparedwithplayersinthe

intermediatetertile,whereasa35%reductionofinjury

riskcomparedwiththetertilewiththelowest

compliancewasnotstatisticallysignificant(p=0.09).

Steffenetal.

[80]2008

FIFA11+warm-

up

Footballplayers

(1091/1001,0%)

52%,compliant>20sessions,non-

compliance>20sessions

Inasub-groupanalysistodeterminewhether

compliancewiththeinterventionprogramcouldhave

influencedtheriskforinjuriesthroughoutthestudy

period,itwasshownthattherewasnodifferenceinthe

injuryincidenceofoverallandacuteinjuriesbetween

thecompliantgroupandthenon-compliantgroup.

Steffenetal.

[84]2013

FIFA11+warm-

up

Footballplayers Intervention1:High,medium,low

compliance:52%,23%,25%.Intervention

2:High,medium,lowcompliance:41%,

41%,18%.Teamcompliancewasdefinedas

Theunadjustedoverallinjuryrateforplayers

categorizedintothehighcompliancegroupwas57%

lowerthantheinjuryrateofplayersinthelow

adherencegroup(IRR=0.43,95%CI0.19to1.00).

2Inthisstudyparticipantswereassignedtothreedifferentstudygroups:anunsupervisedgroup,agroupwhoreceivedcoach-ledworkshopsandagroupwhoreceived

coach-ledworkshopsandon-fieldsupervision.

(129/121/135,0%)2 the11+theproportionofallpossible

sessionswherethe11+wasdelivered,the

numberofteam11+sessions/weekandthe

meannumberofteam11+

exercises/session.

However,adjustingforthecluster,agegroup,levelof

playandinjuryhistory,thisbetween-groupdifference

ininjuryriskwasnotstatisticallysignificant(IRR=0.44,

95%CI0.18to1.06).Nootherdose-response

relationshipbetweenhighandlowadherencetothe

11+andinjuryriskcouldbeidentified.

Steffenetal.

[85]2013

FIFA11+warm-

up

Footballplayers

(68/78/80,0%)2

Intervention1:High,medium,low

compliance:37%,23%,8%.Intervention2:

High,medium,lowcompliance:29%,26%,

23%.Teamcompliancewasdefinedasthe

11+theproportionofallpossiblesessions

wherethe11+wasdelivered,thenumberof

team11+sessions/weekandthemean

numberofteam11+exercises/session.

Nosignificantdifferencesintriplejumpperformance

oroverallriskinjury.Effectofhighadherenceon

sustaininginjuryIRR=0.28(0.1-0.79)

Waldenet

al.[77]

2012

Neuromuscular

training

Footballplayers

(2479/2080,0%)

Compliancedefinedas>1sessionperweek:

52.5%

Anadjustedsubgroupanalysisofcompliantplayers

(1303playersin112interventiongroupclubs,1967

playersin106controlgroupclubs)showeda

statisticallysignificant83%ratereductioninanterior

cruciateligamentinjury(rateratio0.17,0.05to0.57,

P=0.004),aswellassignificantreductionsfor

secondaryoutcomesintheinterventiongroup

comparedwiththecontrolgroup(severekneeinjury

rateratio0.18,0.07to0.45,P<0.001;anyacuteknee

injuryrateratio0.53,0.30to0.94,P=0.03).Analysesof

non-contactanteriorcruciateligamentinjuriesshowed

areductioninratesfavouringtheinterventiongroup.

Thereductionwasstatisticallysignificantonlyforthe

Table1:Studiesthatanalyzetheeffectofcomplianceratesonstudyoutcome

PE=Physicaleducation,RR=RelativeRisk,ITT=Intention-to-treat=PPA=Per-protocol-analysis-treat,IRR=Incidencerateratio,IID=Injuryincidencedensity.

adjustedsubgroupanalysisofcompliers(intention-to-

treatanalysisrateratio0.40,0.13to1.18,P=0.10;

adjustedsubgroupanalysisrateratio0.26,0.07to0.99,

P=0.049).

44

DISCUSSION

Alackofauniformdefinitionofcompliance

Inthestudiespresentedinthisreview,variousmethodswereemployedtodefinemeasureand analyse the effect of compliance. Themost important finding is that, although themajority of studies mention the concept of compliance, there is a large degree ofheterogeneityinthemannerinwhichstudiesdealwiththisconcept.Somestudiesmerelymention compliance in either the introduction or discussionwithout providing furtherdetailsoncomplianceassessmentandcompliancedata.AscanbeseenfromFigure2therearemorestudiesthatprovidecompliancedatathantherearestudiesthatgiveanexplicitdefinitionofcomplianceoroneoftherelatedconstructs.Inotherwords,whilstmanyreportcompliance,amajoritydonotdefinethistermorexplicitlystatehowtheyoperationalizedit.Themajorityofthestudiesreportminimaldetailson:(1)thedefinitionofcompliance,2)how compliance was measured, 3) the frequency bywhich compliance was measured(everyday,week,month),and4)howcomplianceaffectedstudyoutcomes.From1970onwards,therewasaclearincreaseinthenumberofsportinjurypreventionRCTstudies.However,inthelastfewyears(2011-2014)thistrendhasnotcontinuedandthe number of injury prevention RCTs has actually decreased. It is likely that afternumerous efficacy studies, research now focuses on implementation of preventionmeasuresinnon-RCTstudies.Asthesenon-RCTstudiesarenotthetopicofthisreview,theywillnotappearinFigure2.Theimportanceofcompliancereporting

Inordertoevaluatestudyoutcomesinthecontextinwhichtheyareexamined,itisessentialthat studies report the percentage of participantswhohaveactually compliedwith theprescribed intervention. Compliance to an intervention significantly influences theoutcomes of intervention studies, which is clearly illustrated by a number of studiesincludedinthisreview[5,32,71,74,90].Forexample,inthestudybySteffenetal.[5]thatassessed compliance rates to a neuromuscular injury prevention programme, high,intermediateandlowcompliancegroupsweredefined.Theauthor’sPPAfoundthatonlythehighcompliantgroupbenefitedsignificantlyfromtheintervention.

InthestudybyEmery[71]evaluatinghome-basedbalancetraining,participantswhohadconductedmorethan18sessions(outoftherecommended42sessions)in6weekshadachieved a significant improvement in static balance skills. Participants with lowercomplianceratesdidnot improve their staticbalanceskills.Gabbeetal. [90]evaluatedeccentrichamstringexercisesinamateurfootballplayers,ofwhichonly4%ofthosewhowerecompliantwiththeinterventionsustainedaninjury.Playerswhowerenotcomplianttotheinterventionshowednoreducedinjuryriskwhencomparedtothecontrolgroup.Hagglundetal.[74]reportedsimilaroutcomes,showingthatonlyinteamswithhighestcompliancetoaneuromusculartrainingprogramasignificantreductionininjuryrateswasfound.Finally,thestudyofHupperetsetal.[32]suggestedthatahighercompliancewouldhaveresultedinfewerinjuries.Inthatstudy,only23%ofparticipantswerefullycompliant.Inasecondaryanalysisinasubsequentpaper,itwasindeedshownthatthesmallgroupof

45

participantswithhighcompliancewasresponsibleforthepositiveeffectoftheexerciseprogramonrecurrentinjuryrisk[92].

Informationontherateofcomplianceanditseffectonstudyoutcomescanbeshapedintoaclearmessageforthetargetgroupsinvolved;theyshouldbeinformedaboutthenumberoftrainingsessionstheyshouldatleastparticipateintoreducetheirriskofsustaininganinjury.Providinginformationoncomplianceratesandtheeffectofthosedifferentratesonstudyoutcomesmightincreasethepracticalusabilityofstudyresultsforthetargetgroup.

AcknowledgmentoftheCONSORTStatement

The CONSORT statement argues that, in order to evaluate both efficacy (with theassumption of full compliance and no recognition of implementation barriers) andeffectiveness(thereallifeadoptionofanintervention),researchersshouldanalysestudyresultsusingITT,PPAandagradedcompliancemeasure[7].Thelatterreferstotheextenttowhichparticipantshavecompliedwiththeprogramandwhateffectthishashadontheoutcome.

Inadditiontothediversitybywhichcomplianceisdefined,measuredandadjustedforintheanalysis,thestudiesincludedinthisreviewshowalargedegreeofheterogeneityintheuseofITT,PPAorgradedcompliance.

Thirty-sevenstudieshaveusedoneormoreoftherecommendedanalyses.Twenty-eightstudies[16,17,27,29,32,34,37-40,42,44,50,52,71,72,75-82,84,93-95]usedITTanalysis,oneused PPA [19] and eight studies [31,43,47,58,88,90,96,97] used both analyses (seeElectronicSupplementaryMaterialAppendixS1). It isclearthat,althoughtheCONSORTstatementclearlyacknowledgestheimportanceofcomplianceandhence,providesastepforwardinimprovingthequalityofinterventionstudies,thereisstillalackofuniformity.Whatisneededisauniformwayinwhichcomplianceisdealtwith.

Furtherresearch

Further research needs toconfirmwhichmeasures provide themost valid and reliableassessment of compliance. Although various methods have been used to measurecompliance (e.g. the use of written, vocal or online self-reports, supervision and/orunscheduledvisits),eachmethodhasitsownlimitations.Participantscanincorrectlyrecalltheir activities or provide socially desirable reports on self-reported measures ofcompliance. In addition, a uniform definition of compliance and a categorization ofcomplianceratesmightincreasethepossibilityofcomparingtheeffectivenessofdifferentinjurypreventionprograms.ThemainweaknessofthecurrentstudyisthatitonlyincludedRCTs.ItwouldbeofinteresttoconductasimilarreviewthatincludesbothRCTsandless-controlledstudiestoidentifyadherencetosportinjuryinterventionstudiesinwhichthesettingislesscontrolled.

46

CONCLUSION

Injurypreventionstudiesvarysignificantlyinthewaytheydefine,measureandadjustforcompliance.Whilethemajorityofthesestudiesmentiontheconceptofcompliance,onlyonefifthofthestudiesgaveamoredetailedaccountofhowcomplianceratesinfluencetheirstudyresults.Thestudiesthatdidaccountforcompliance,demonstratethatthelevelofcompliance can have a significant effect on study outcomes. Valid and reliable tools tomeasureandreportcomplianceneedtobedeveloped,matchedtoauniformdefinitionofcompliance.Althoughcurrentguidelinesforreportingofstudieshaveincreasedawarenessoftheneedforcompliancemeasurements,thewaythesemeasurementsareexecutedandreportedstilldealswithalargedegreeofheterogeneity.

COMPLIANCEWITHETHICALSTANDARDS

FundingThis study was funded by the Netherlands Organisation for health research anddevelopment(ZonMW),grantnumber525001003.ConflictsofInterestMiriamvanReijen,IngridVriend,WillemvanMechelen,CarolineFinchandEvertVerhagendeclarethattheyhavenoconflictsofinterestrelevanttothecontentofthisreview.

47

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ElectronicSupplementaryMaterialAppendixS1:INCLUDEDSTUDIES

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IISectionIII

SectionIV

Authors[reference]

Year

InterventionFurlanScore

Iscompliancementioned?

Whatisthetermused?

Iscompliancemeasured?

Howiscompliancemeasured?*

Arecompliance

ratesprovided?

Arecompliance

ratesadjustedfor?

Krausetal.

[52]1970 Useofahelmet 4 YES Use YES

Visualcheckby

supervisorYES NO

Ekstrandetal.

[24]1983

Prophylactic

exercisesanduseof

ankletape

1 YES Attendance YES Reportbysupervisor NO NO

Milgrometal.

[59]1985

Useoforthotic

insoles1 YES Use YES

Visualcheckby

supervisorYES NO

Smithetal.

[98]1985

Useoforthotic

insoles1 NO NO NO NO

Gardneretal.

[99]1988

Useoforthotic

insoles3 YES Compliance NO NO NO

Schwellnuset

al.[100]1990

Useofneoprene

insoles4 YES Compliance YES

Visualchecksbyresearchers&self-report.Military

study

YES NO

Sitleretal.

[60]1990 Useofakneebrace 3 YES Compliance YES

Visualcheckby

researchers.Military

study

YES NO

Milgrometal.

[53]1992 Useofmodifiedshoes 2 YES Use YES

Visualcheckby

supervisors.Military

study

NO NO

Schwellnus

andJordaan

[48]

1992Useofcalcium

supplements4 YES Compliance YES

Reportby

supervisor.Military

study

NO NO

Barrettetal.

[61]1993

Useofdesignated

shoes6 YES Use YES

Visualcheckby

supervisorYES NO

VanMechelen

etal.[33]1993

Warm-up,cool-down

andstretching

exercises

2 YES Compliance YES Self-report YES NO

Sitleretal.

[62]1994 Useofananklebrace 2 YES Compliance YES

Visualcheckby

researchers.Military

study

YES NO

Surveetal.

[25]1994 Useofankleorthoses 1 YES Compliance YES Reportbysupervisor NO NO

Caraffaetal.

[101]1996

Proprioceptive

training2 YES Cooperation NO NO NO

Bengaletal.

[102]1997 Useofakneebrace 2 NO NO NO NO

Jorgensenet

al.[103]1998 Educationalvideo 3 NO NO NO NO

Popeetal.

[104]1998 Stretchingexercises 5 NO NO NO NO

Buchmanet

al.[105]1999

Useofarginine

supplements3 NO NO NO NO

Finestoneet

al.[54]1999

Useofadesignated

shoe4 YES Compliance YES

Visualcheckbysupervisors.Militarystudy

NO NO

Holmeetal.

[106]1999

Rehabilitation

exercises3 NO NO NO NO

Wedderkopp

etal.[107]1999

Ankledisctraining

andwarm-up

exercises

1 NO NO NO NO

Heidtet

al.[108]2000

Preconditioning

program3 NO NO NO NO

Popeetal.

[93]2000 Stretchingexercises 4 YES Attendance YES

Visualcheckbysupervisorsand

visitsbyresearchers.Militarystudy

NO NO

Sodermanet

al.[67]2000

Balanceboard

training1 YES

Compliance

andinternal

dropout

YES

Self-reportandreportbysupervisors

YES YES

Ronningetal.

[91]2001

Useofawrist

protector4 NO NO NO YES

Larsenetal.

[88]2002 Useofshoeorthoses 7 YES Compliance YES Unknown YES YES

Larsenetal.

[68]2002

Strengthening

exercises6 YES Compliance YES

Self-reportandvisualcheckbyresearchers

NO NO

Macholdetal.

[58]2002

Useofanwrist

protector6 YES Compliance YES

Visualcheckby

supervisorsYES YES

Torkkietal.

[109]2002

Useofdesignated

shoes5 YES Adherence YES Self-report YES NO

Asklinetal.

[110]2003

Preconditioning

exercises3 NO NO NO NO

Knapiketal.

[56]2003

Physicalreadiness

training3 NO YES

Visualcheckby

supervisors.Military

study

YES NO

Pernaetal.

[111]2003 Stresstherapy 5 NO NO NO NO

Wedderkopp

etal.[34]2003 Ankledisctraining 1 YES Compliance YES Self-report NO NO

Finestoneet

al.[112]2004 Useoffootorthoses 5 YES Use YES

Visualcheckby

supervisors.Military

study

YES NO

Koltetal.

[113]2004 Stresstherapy 2 NO NO NO NO

Milgrometal.

[47]2004

Useofrisedronate

supplement4 YES Compliance YES

Visualcheckby

supervisors.Military

study

YES NO

Sherryand

Best[35]2004

Rehabilitation

exercises1 YES Compliance YES Self-report YES NO

Stasinopoulos

[114]2004

Proprioceptive

exercisesand

externalsupport

2 YES Compliance NO NO NO

vanTiggelen

etal.[115]2004 Useofabrace 2 NO NO NO NO

Verhagenetal.

[26]2004

Balanceboard

training4 YES Compliance YES Reportbysupervisor NO NO

Arnasonetal.

[116]2005 Educationalvideo 3 NO NO NO NO

Barbicetal.

[72]2005 Useofamouthguard 4 YES Compliance YES

Reportbysupervisorand

visitsbyresearchers

YES NO

Emeryetal.

[71]2005

Balanceboard

training5 YES Compliance YES

Self-reportandphonecallsbyresearchers

NO YES

Finchetal.

[63]2005 Useofamouthguard 3 YES Compliance YES

Visualcheckby

supervisorsNO NO

Milgrometal.

[96]2005 Useoffootorthoses 2 YES Compliance YES

Visualcheckbysupervisorsand

visitsbyresearchers.Militarystudy

NO NO

Olsenetal.

[117]2005 Warm-upexercises 7 YES Compliance YES Reportbysupervisor YES NO

Gabbeetal.

[90]2006

Preconditioning

exercises4 YES Compliance YES Reportbysupervisor YES YES

Mcguineand

Keene[28]2006 Balancetraining 5 YES Compliance YES Reportbysupervisor NO NO

Mickeletal.

[64]2006

Useofabraceand

tape4 YES Compliance YES

Visualcheckby

supervisorNO NO

Withnalletal.

[94]2006 Useofinsoles 5 NO NO NO NO

Cobbetal.

[43]2007 Useofcontraceptives 5 YES Compliance YES Self-report YES YES

Emeryetal.

[69]2007 Balancetraining 6 YES Compliance YES

Self-reportandreportby

supervisors.YES NO

Hagglundet

al.[29]2007

Rehabilitation

exercises5 YES Compliance YES Reportbysupervisor YES NO

Kekkonenet

al.[44]2007 Useofprobiotics 7 YES Adherence YES Self-report YES NO

Mohammadi

[118]2007

Proprioceptive&

strengthexercises

plususeoforthoses

2 YES Compliance NO NO NO

Myklebustet

al.[17]2007 Balancetraining 3 YES Compliance YES Reportbysupervisor YES YES

Nohetal.[36] 2007Autogenicand

relaxationtraining3 YES Adherence YES Self-report YES NO

Brushojetal.

[87]2008

Strength,flexibility

andcoordination

exercises

6 YES Compliance YES Reportbysupervisor YES NO

Buistetal.

[37]2008 Gradedtraining 5 YES Compliance YES Self-report YES NO

Cumpsetal.

[38]2008 Preventiveexercises 4 YES Compliance YES Self-report YES NO

Engebretsen

etal.[31]2008 Targetexercises 2 YES Compliance YES Self-report YES YES

Fredbergetal.

[21]2008

Prophylacticand

stretchingexercises1 YES Compliance YES Reportbysupervisor YES NO

Gilchristetal.

[19]2008 Warm-upexercises 4 YES Compliance YES Reportbysupervisor YES NO

Lappeetal.

[97]2008

Useofcalciumand

vitaminD

supplements

6 YES Use YES

Visualcheckandinterviewbyresearchers.Militarystudy

NO NO

Pasanenetal.

[16]2008

Neuromuscular

training6 YES

Compliance

andadherenceYES Reportbysupervisor YES YES

Soligardetal.

[79]2008 Warm-upexercises 5 YES Compliance YES

Reportbysupervisor;phonecallsandvisitsbyresearchers

YES YES

Steffenetal.

[85]2008

Warm-upexercises

(FIFA11+)5 YES Compliance YES

Reportbysupervisor;phonecallsandvisitsbyresearchers

YES YES

Holmichetal.

[73]2009 Preventiveexercises 4 YES Participation YES

Reportbysupervisorand

visitsbyresearchers

NO NO

Hupperetset

al.[32]2009

Proprioceptive

exercises5 YES Compliance YES Self-report YES YES

Knapiketal.

[55]2009

Useofdesignated

shoes3 NO YES

Visualcheckby

supervisors.Military

study

YES NO

McIntoshetal.

[76]2009

Useofpadded

headgear4 YES Compliance YES

Reportbysupervisorsand

YES YES

visitsbyresearchers

Childsetal.

[132]2010

Corestabilisation

exercises5 NO NO NO NO

Collardetal.

[119]2010 Preventiveexercises 4 NO NO NO NO

Eilsetal.

[120]2010

Proprioceptive

exercises4 NO NO NO NO

Emeryand

Meeuwisse

[66]

2010Neuromuscular

training3 YES Adherence YES

Self-reportandreportbysupervisors

YES NO

Jamtveldtet

al.[39]2010 Stretchingexercises 5 YES Compliance YES Self-report YES NO

Kianietal.

[20]2010

Motorskillexercises

+education5 YES

Compliance

andadherenceYES Reportbysupervisor YES YES

Knapiketal.

[121]2010

Useofcustomized

shoes5 NO NO NO NO

Soligardetal.

[81]2010 Warm-upexercises 5 YES Compliance YES

Reportbysupervisor;phonecallsandvisitsbyresearchers

YES YES

Belloetal.

[122]2011

Stabilization

exercises2 NO NO NO NO

Coppacketal.

[22]2011 Preventiveexercises 7 YES Compliance YES Reportbysupervisor YES NO

Franklyn-

Milleretal.

[123]

2011 Useofshoeorthoses 5 NO NO NO NO

Georgeetal.

[65]2011

Stabilization

exercises6 YES Compliance YES

Visualcheckby

researchers.Military

study

NO NO

Gomesetal.

[124]2011

VitaminCandE

supplements6 NO NO NO NO

Kinchingtonet

al.[49]2011

Useofdesignated

footwear4 YES Compliance YES Reportbysupervisor YES NO

Labellaetal.

[70]2011

Neuromuscular

training5 YES Compliance YES

Self-reportandreportbysupervisors

YES NO

Mattilaetal.

[82]2011 Useoffootorthoses 9 YES Compliance YES

Self-reportandvisualcheckbyresearchers

YES NO

Mcguineetal.

[50]2011 Useofananklebrace 5 YES Compliance YES Reportbysupervisor NO NO

Parkkarietal.

[40]2011

Neuromuscular

training7 YES Compliance YES Self-report YES NO

Petersenetal.

[30]2011 Eccentrictraining 7 YES Compliance YES Reportbysupervisor YES NO

Ryanetal.

[45]2011

Useofdesignated

shoes2 YES Use YES Self-report NO NO

Shihetal.

[125]2011 Useoffootorthoses 5 NO NO NO NO

Beijsterveldt

etal.[78]2012

Preventivetraining

(FIFA11+)3 YES Compliance YES

Reportbysupervisorsand

visitsbyresearchers

YES NO

Bredeweget

al.[95]2012

Preconditioning

program4 YES

Compliance,

adherenceand

exposure

YES Self-report YES NO

Hidesetal.

[126]2012

Motorcontrol

training4 NO NO NO NO

Longoetal.

[83]2012

Preventivetraining

(FIFA11+)7 YES Compliance YES

Reportbysupervisor;phonecallsandemailsby

researchers

YES YES

Mcguineetal.

[51]2012 Useofanklebrace 4 YES Compliance YES Reportbysupervisor NO NO

Waldenetal.

[77]2012 Warm-upexercises 6 YES Compliance YES

Reportbysupervisorsand

visitsbyresearchers.

YES YES

Cusimanoet

al.[127]2013

Educationalvideo

andbrochure6 NO NO NO NO

Hagglundet

al.[74]2013

Neuromuscular

training2 YES Compliance YES

Reportbysupervisorsand

visitsbyresearchers

YES YES

Kristetal.

[75]2013

Preventivetraining

(FIFA11+)5 YES Compliance YES

Reportbysupervisorsand

visitsbyresearchers

YES NO

Steffenetal.

[84]2013

Preventivetraining

(FIFA11+)2 YES Adherence YES

Reportbysupervisorsand

visitsbyresearchers

YES YES

Steffenetal.

[5]2013

Preventivetraining

(FIFA11+)6 YES Adherence YES

Reportbysupervisorsand

visitsbyresearchers

YES YES

Asklingetal.

[128]2014

Rehabilitation

exercises4 NO NO NO NO

Drobnicetal.

[129]2014 Useofcurcumin 8 NO NO NO NO

Janssenetal.

[42]2014

Neuromuscular

traininganduseofan

anklebrace

3 YES Compliance YES Self-report YES NO

Sebelienetal.

[130]2014

Strengthening

exercises5 NO NO NO NO

Sharmaetal.

[131]2014

Gaitretrainingand

flexibilityexercises4 NO NO NO NO

Theisenetal.

[46]2014 Useofmidsole 6 YES Use YES Self-report YES NO

71

CHAPTER4 Increasingcompliancewithneuromusculartrainingtopreventanklespraininsport:doesthe‘Strengthenyourankle’mobileAppmakeadifference?Arandomisedcontrolledtrial.

MiriamvanReijenIngridVriendVictorZuidemaWillemvanMechelenEvertVerhagenBritishJournalSportsMedicine2016Digitalobjectidentifier(doi):10.1136/bjsports-2015-095290

four.

72

ABSTRACT

BackgroundE-healthhasthepotentialtofacilitateimplementationofeffectivemeasurestopreventsportsinjuries.

Aim:Weevaluatedwhetheraninteractivemobileapplicationcontainingaproveneffectiveexerciseprogrammetopreventrecurrentanklesprains,resultedinhighercomplianceascomparedtoregularwrittenexercisematerials.

Methods220athletesparticipatedinthisrandomisedcontrolledtrialwithafollow-upofeight-weeks; 110 athletes received a booklet explaining an eight-week neuromusculairtrainingprogram;110athletesthesameprograminaninteractivemobileApp(‘Strengthenyourankle’).Theprimaryoutcomewascompliancewiththeexerciseprogram.Secondaryoutcomemeasurewastheincidencedensityofself-reportedrecurrentanklesprains.

ResultsThemeancompliancetotheexerciseschemewas73.3%(95%CI:67.7-78.1)intheAppgroup,comparedto76.7%(95%CI:71.9-82.3)intheBookletgroup.Nosignificantdifference in compliance was found between groups. The incidence densities of self-reportedtime-lossrecurrenceswerenotsignificantlydifferentbetweenbothgroups(HR3.07;95%CI0.62-15.20).

Summary:Thisstudyshowsthatthemethodof implementingtheexercisesbyusinganApporaBookletdoesnotleadtodifferentcompliancerates.

Newfindings:TheuseofamobileApporaBookletleadtosimilarcomplianceandinjuryratesintheshortterm.

Trialregistration

TheNetherlandsNationalTrialRegisterNTR4027.TheNTRispartoftheWHOPrimaryRegistries.

73

BACKGROUND

Ankleinjuriesarethesecondmostcommonsportsrelatedinjuriesandanklesprainisthemostcommontypeofankleinjury.Anklesprainmayaccountforasmuchas80%ofallankleinjuries.Theincidenceofankleinjuryandanklesprainisespeciallyhighinpopularsportsasrugby,(indoor)soccer,triathlon,handball,volleyballandbasketball[1].Bothexternallyappliedsupports (i.e. tapingorbracingof theankle), aswellasneuromuscular trainingprogramspreventrecurrentanklesprainsandarecost-effectiveness[2,3,5].

Despite these cost-effective interventions, large-scale community uptake of thesemeasures,andthusactualpreventionofanklesprains,islagging[4,5].Thecost-effectiveneuromuscular training program [3,6] has suffered from poor compliance [4] and itspreventive effect was achieved solely among a subsample of compliant athletes [5].Althoughanalyseshavebeenperformedusinganintention-to-treatapproach,thereisstillalotofeffectivenesstogainbyincreasingcompliancewithpreventivemeasures.

E-health has potential to bridge this so-called implementation gap [7]. The companyVeiligheidNL developed an interactive mobile application: 'Strengthen your ankle'('Versterk je enkel', free for iOS and Android) that contains the cost-effectiveneuromusculartrainingprogram.Althoughmobileappsareplentifulandhavethecachetoftechnologicaladvancement,thevalueofthisapproachforinjurypreventionhasnotbeenevaluated formally [8].Consequently,weevaluatedwhether the ‘Strengthenyourankle’Appresultedinhighercompliancewiththeneuromusculartrainingprogramascomparedtotheregularwrittenexercisematerials.

METHODS

Design

Thisstudywasarandomisedcontrolledtrial.Adetaileddescriptionofthestudyprotocolhas been published elsewhere [9]. The study design, procedures and informed consentprocedure were approved by the Medical Ethics Committee (2013/248) of the VUUniversityMedicalCenterAmsterdam(VUmc)theNetherlands.Thetrial isregisteredintheNetherlandsTrialRegistry(NTR4027).

Participants

ParticipantswererecruitedfromOctober2013toApril2014throughphysiotherapyandsportphysicianpractices,nationalsportfederations’websites,digitalnewslettersandanopeninvitationviasocialmedia,theInternetandwrittenmedia.Activesportsparticipants(athletes)between18and70yearsofagewhohadsustainedananklesprainwithinthepast twomonths,andwhohadaccess toamobile phone (eitherAndroid or iOS),wereeligibleforinclusion.Respondentswereexcludediftheyhadsustainedaninjuryotherthanalateralanklespraininthesameankleintheprecedingyear(e.g.,fractureoftheankle).Beforeinclusion,themainauthorcontactedallpotentialparticipantsbyphonetoconfirmstudyeligibility.TherecruitmentofparticipantsisshowninFigure1.

74

Figure1|Flowchartofparticipantrecruitmentandfollow-up

SampleSize

Samplesizecalculationswerebasedupontheprimaryoutcomemeasurecomplianceandoriginated from previously established compliance rates to the same program whenadvocated throughwrittenmaterials [4].Full compliancerates in thewrittenmaterials’group were expected to be around 25%. A doubling of this rate to at least 50% wasconsideredtobeclinicallyrelevant.Baseduponabetaof0.90andanalphaof0.05,atotalof158athleteswererequireddividedacrossbothstudygroups.Assumingadropoutrateof20%,asampleof190participantswascalculated.

Randomisationprocedure

Afterparticipantshadfinishedanklespraintreatmentbymeansofusualcare,andafterthebaseline questionnaire and the informed consent were received, participants wererandomly assigned to one of two study groups. The control group received theneuromuscular training program on paper (Booklet group) and the intervention group

75

receivedtheneuromusculartrainingprogramthroughtheApp(Appgroup).Participantswereallocatedtothestudygroupsthrougharandomnumbergenerator.

Interventions

Allparticipantsreceivedtheneuromusculartrainingbalanceboard(machU/MSGEuropeBVBA).BoththeBookletandtheAppcontainedthesameneuromusculartrainingprogram.TheAppcanbedownloadedforfreefromboththeAppStore(http://apple,co/1EcHyFP)and theGooglePlaystore (http://bit,ly/1AHuZkB).Whereas theAppprovided theuserwithinstructionalvideosandverbalinstructions,theBookletincludedonlypicturesoftheexercises thatneeded tobeperformed.Theembeddedneuromuscular trainingprogramconsistedofsixdifferentexercisestobeperformedduringthreesessionsaweek,withamaximumdurationof30minutespersession,foraperiodof8weeks.Exercisesgraduallyincreasedindifficultyandloadduringthecourseofeightweeks.Thisprogramhasbeenshowntobecost-effectiveinreducingrecurrentanklesprain[6].Afulldescriptionoftheprogramhasbeenpublishedelsewhere[4].Figure2showstheexercises,andTable1givestheschemethatparticipantswererequiredtofollow.

A:One-leggedkneeflexionVariations:1. Onanevensurface2. Onanevensurface,eyesshut3. Onabalanceboard

B:ToestandVariations:1. Withhandhold2. Withouthandhold

C:One-leggedstanceVariations:1. Onanevensurface2. Onanevensurface,eyesshut3. Onabalanceboard

D:Runner’sposeVariations:1. Onanevensurface2. Onanevensurface,eyesshut3. Onabalanceboard

E:Cross-leggedswayVariations:1. Withhandhold2. Withouthandhold3. Withouthandhold;eyesshut4. Onabalanceboard

F:ToewalkVariations:1. Walking2. Jumping

Figure2|Theexercisesoftheneuromusculartrainingprogram

76

Table1|Exerciseschemeofthe8-weekneuromusculartrainingprogram

Training(threetimesaweekforaperiodof8weeks;increaseddifficultylevel1to4)

Exercise

Week1 Week2 Week3 Week4 Week5 Week6 Week7 Week8

1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3

A 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3

B 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2

C 1 1 1 1 2 2 2 2 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3

D 1 1 1 1 2 2 2 2 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3

E 1 1 1 1 1 1 2 2 2 2 2 2 3 3 3 3 4 4 4 4 4 4 4 4

F 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2

Baselinemeasurement

An online baseline questionnaire collected information from each participant ondemographicvariables,physicalcharacteristics,sportsandinjuryhistory,useofpreventivemeasures, severity and received treatment and/or rehabilitation of the current anklesprain.

Outcomemeasures

Theprimaryoutcomemeasurewascompliancetotheexerciseschemeprescribedintheneuromusculairtrainingprogram.Compliancewasdefinedastheparticipant’sfollowingofthe prescribed intervention, i.e. the scheme of exercises (Table 1) [10]. Compliancemeasurements commenced after the start of the allocated intervention and took placeweeklyforthedurationoftheprogram(eightweeks).Participantsreceivedarequestbyemailtocompleteanonlinecompliancequestionnaire.Afterthreedaysareminderwassentin case of non-response. These weekly measurements gathered information for eachparticipantonthenumberofexecutedexercisespersessionandthenumberofexecutedsessionsperweek.Fromthisinformation,weeklycompliancerateswerecalculatedasthepercentageofprescribedexercisesconducted,bymultiplyingthepercentageperexercisewiththenumberoftimestheseexerciseswereperformedperweek.Previousresearchhasshownthat,inorderfortheneuromuscularprogramtobeeffective,participantshavetobehighlycompliantwiththeexercisescheme10.Inthisstudy,acompliancerateofover75%wasconsideredadequate.

77

Exposureandinjuryregistration

Secondaryoutcomemeasurewas the incidencedensityof self-reportedrecurrentanklesprains.Injuryincidencedensitywasdefinedasthenumberofrecurrentanklesprainsper1,000 hours of sports exposure. During the eight weeks follow-up, in addition to thequestions regarding compliance, participants were asked weekly about their hours ofsportsexposureandwhether theyhadsustainedananklesprain in thepreviousweek.Ankle sprain recurrencewas defined as a self-reported inversionmoment of the sameankle. Both an episode of giving-was, aswell as a grade 1, 2 or 3 ankle sprainswereregistered.Self-reportedrecurrentanklesprainswerefurthercategorizedtoseveritybylooking at recurrences that had led to time-loss, defined as the discontinuity of (sport)activityand/ormissing(partof)thenextplanned(sports)activityduetotherecurrence[4].Thistime-losscategorizationisinlinewiththeaccepteddefinitionofananklesprain[11].

Statisticalanalyses

MeanbaselinedifferencesbetweentheAppandtheBookletgroupweredeterminedusingan independent samples t-test for continuous data (age, weight, height, exposure) andFisher’s exact test (withMonte Carlo 95% confidence interval simulation due to smallnumberofsamples)forcategoricaldata(levelofsport,severityofanklesprain,gender).Baselinemeasurementswerebasedonthetotalnumberofparticipants(n=220)thatwereallocatedtoeitheroneoftheinterventions.

Whilecompliancewasnotnormallydistributed,weeklyandoverallcompliancemeansandcorresponding 95%CIwere obtained throughbiascorrected accelerated bootstrappingwith1,000bootstrapsamples.Meanweeklyandoverallcompliancerateswerecomparedbetweengroupsbymeansofanon-parametricMann-WhitneyUtest.Cox regression analyses compared risk of self-reported and time loss recurrent anklesprainsbetweenthegroups.Analyseswerecheckedforconfoundingbybaselinevariables,butnonewerefound.Genderwasfoundtobeaneffectmodifier;consequently,analysesweredoneseparatelyforbothmalesandfemales.Allanalyseswereconductedaccordingtotheintention-to-treatprincipleanddifferenceswereconsideredsignificantwithasignificancelevelof.05.

RESULTS

Recruitment

Between October 2013 and April 2014, a total of 220 participantswere recruited andrandomized to one of the two groups (Figure 1). After randomization, a number ofparticipantsindicatedthattheynolongerwishedtoparticipateinthestudyduetotimerestraintsor lackofmotivation.Fortheremainderofthestudyperiod,theircomplianceratesweresetto0%.Asmallnumberofparticipantshadtoleavethestudyduetoanon-ankle injury (n=4) or due to personal reasons (n=4). The compliance rates of these

78

participantswereonlyincludedfortheweekstheyparticipatedinthestudy.Atbaseline,bothgroupswerecomparableregardingallvariablesmeasured(Table2).

Table2Baselinecharacteristicsofthestudypopulation.Numbersarepresentedaspercentageofthepopulation(%)orasthemeanwithcorrespondingstandarddeviation(mean±SD).

Combined App Booklet

Participants(n) 220 110 110

Numberoffemales(%) 50.0% 50.0% 50.0%

Age(years) 37.9±13.4 37.6±13.1 38.1±13.7

Weight(kg) 73.3±12.8 73.0±13.0 73.7±12.6

Height(cm) 177.3±9.1 177.0±8.9 177.7±9.4

Levelofsport(%)

Competitive.international

Competitive.national

Competitive.regional

Recreational.organised

Recreational.unorganised

8,2

29,1

69,1

50,9

42,7

1,8

17,3

36,4

22,7

21,8

6,4

11,8

32,7

28,2

20,9

Severityofinclusionsprain(%)

Grade1

Grade2

Grade3

Unknown

84,6

58,2

16,4

40,9

42,7

30,9

9,1

17,3

41,8

27,3

7,3

23,6

Compliance

Overthecomplete8weeks,themeancompliancetotheexerciseschemewas73.3%(95%CI:67.7-78.1)intheAppgroupascomparedto76.7%(95%CI:71.9-82.3)intheBookletgroup(Table3).Nosignificantdifferenceinmeanoverallcompliancewasfoundbetweengroups, nor for males or females. In both groups 82 out of 110 participants (74.5%)complied tomore than75%of the program. Compliance gradually declined over the 8weeksinbothgroups(Figure3).

79

Table3|Meanweeklyandoverallcomplianceandcorresponding95%CIinbothstudygroups.

Overall Male Female

App Booklet App Booklet App Booklet

Week190.2%

(84.4-94.9)91.3%

(86.8-95.3)

91.5%(84.0-98.2)

90.7%(83.9-95.8)

89.0%(82.3-95.2)

91.9%(85.3-97.1)

Week278.3%

(70.9-84.8)82.3%

(75.2-88.4)

80.6%(71.4-90.3)

82.0%(72.5-90.9)

76.0%(65.2-85.1)

82.5%(72.8-90.9)

Week376.8%

(69.7-83.5)78.9%

(72.0-84.6)

76.7%(67.1-85.5)

79.2%(70.1-87.3)

76.9%(67.7-85.8)

78.7%(69.2-86.4)

Week472.7%

(65.2-79.7)75.5%

(67.8-82.6)

70.6%(61.0-80.3)

70.5%(59.3-81.4)

75.0%(64.9-84.9)

80.0%(70.4-88.0)

Week567.1%

(58.9-74.2)75.3%

(67.2-82.8)

68.5%(57.9-78.6)

71.2%(58.7-82.2)

65.6%(54.5-75.6)

78.6%(69.3-88.3)

Week670.2%

(61.7-77.8)67.9%

(60.4–75.7)

70.7%(60.1-81.3)

59.2%(46.1-70.1)

69.6%(58.1-79.9)

74.9%(64.9-84.5)

Week763.3%

(54.2-71.9)70.5%

(62.8-77.9)

58.2%(45.7-70.3)

64.9%(51.0-77.2)

68.8%(56.1-80.3)

75.1(64.3-85.0)

Week864.1%

(55.7-72.5)66.2%

(57.7-74.6)

61.6%(50.3-73.9)

57.4%(42.3-71.3)

66.8%(53.6-79.2)

73.0%(61.0-83.2)

Overall73.3%

(68.0-78.5)76.7%

(71.7-81.9)

71.8%(63.9-78.6)

75.2%(67.2-81.6)

74.8%(67.1-82.0)

78.2%(70.5-84.9)

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Figure3 |Meanweeklycomplianceratesandcorresponding95%CIofbothgroupsacross the8weeksofthe

neuromusculartrainingprogram.

Exposureandrecurrentinjury

Intotal,participantstookpartin2,429hoursofsportintheAppgroupand2,547hoursofsportintheBookletgroupduringtheeight-weekprogram.Intheeightweeksoftheexerciseprogram 93 self-reported recurrent ankle sprains were reported, resulting in injuryincidencedensitiesofrespectively25.3self-reportedrecurrencesper1,000hours(95%CI:18.0-32.7)intheAppgroup,and25.6self-reportedrecurrencesper1,000hours(95%CI:18.3-32.9)intheBookletgroup(Table4).Theinjuryincidencedensitiesoftime-lossanklesprainswererespectively0.82time-lossrecurrencesper1,000hours(95%CI:-0.3-2.0)intheAppgroup,and2.36 time-loss recurrencesper1,000hours (95%CI:0.5-4.2) in theBookletgroup.Nosignificantdifferencesininjuryincidencedensitiesbetweengroupswerefoundforeitherself-reportedortimelossrecurrentinjuries.

Genderactedasaneffectmodifierintherelationshipbetweengroupallocationandinjuryrecurrenceoutcome.Nosignificantdifferenceswerefoundbetweengenders.

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Table4Injuryincidencedensity(IID)ofself-reportedandtimelossanklesprainrecurrences(95%CI)per

1,000hofsportsparticipation,aswellastheHazardRatio(95%CI)derivedfromCoxregressionanalyses.

Recurrentanklesprain App Booklet

Overall n IID n IID HR

Self-reported 46 25.3

(18.0-32.7)

47 25.6

(18.3-32.9)

1.04

(0.69–1.56)

Timeloss 2 0.82

(-0.3-2.0)

6 2.36

(0.5-4.2)

3.07

(0.62–15.20)

Male

Self-reported 21 17.0

(9.7–24.2)

11 10.8

(4.4–17.1)

0.64

(0.31–1.34)

Timeloss 1 0.7

(-0.7–2.0)

3 2.7

(-0.4–5.8)

3.95

(0.41–38.02)

Female

Self-reported 25 43.3

(26.3–60.3)

36 44.2

(29.8–58.7)

1.10

(0.66–1.85)

Timeloss 1 1.0

(-1.0–3.1)

3 2.1

(-0.3–4.5)

2.65

(0.27–25.14)

DISCUSSION

Wefoundthatthemethodofimplementingthe‘StrengthenyourAnkle’exercisescheme,byusinganApporaBooklet,didnot lead tosignificantdifferentmeanoverall compliancerates. Also, the percentage of participants thatwere highly compliantwas not differentbetweengroups.Inbothgroups74.5%ofparticipantscompliedwiththeneuromusculartrainingprogram.

Comparisonwithpreviousstudies

Thecurrent study is the first tocomparecompliancerates toapreventive interventionprogramundertheinfluenceofdifferentimplementationmethods.Twopreviousstudieshavetestedtheeffectivenessofthesameneuromusculartrainingprogramusingwritten

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materials,andbothstudiesreportedcompliancerates[4,5].Thepercentageofparticipantswhowere fully compliant during the twomonths of the programwas as low as 23%4.Janssenetal.[5]describedfullcomplianceof45%.Inthecurrentstudy,thepercentageofparticipantsthatwerehighlycompliantwas65%,Janssenetal.[15]arguedthatatthetimeof their study the neuromuscular training program was more widely accepted in theNetherlandsthansomeyearsbefore,explainingthehighercomplianceratesintheirstudy.It is possible that the neuromuscular training program at the time of our study hasincreased acceptance in practice even further. In addition, the previous studies used aprinted-paperwithasimplelay-out.BoththeBookletandtheAppusedinthecurrentstudywereupdatesofthematerialsthathavebeenusedinthepreviousstudies.WespeculatethattheBookletandtheAppemployedinourstudymayhavehadamoreattractiveformatthatresultedinincreasedcompliancerates.

Effectoninjuries

Injury incidence densities of self-reported recurrences between theApp group and theBookletgroupwerenotsignificantlydifferent.Intwopreviousstudiesthatevaluatedthesameneuromusculartrainingprogram,reductionsininjuryriskwereobservedundertheinfluenceoftheprogram[4,5].Janssenetal.[5]reportedanoverallinjuryincidencedensityof2.51recurrentanklesprainsper1,000hofsport(95%CI:1.51-3.42)inthegroupthatfollowedtheprogram.Hupperetsetal.[4]foundananklespraininjuryincidencedensityof1.86 per 1,000h of sport (95% CI: 1.28-2.75). These injury incidence densities areconsiderablylowerthanfoundinourstudy.Amaindifferencebetweenthepreviousstudiesand the current study is that an inversionmoment (giving-way)wasalso counted as arecurrent event in the current study. Hence this may explain the disparity in injuryincidencedensitiesbetweenourstudyandpreviouslyreportedinjuryincidencedensities.Comparingonlytheinjuryincidencedensitiesofrecurrentinjuriesthatledtotime-loss,theresultsofHupperetsetal.[4](0.65per1,000hofsport;95%CI:0.38-0.92),andJanssenetal.[5](0.95per1,000hofsport;95%CI:0.39-1.51)aremorecomparabletoourfindings.

WenoteatrendforAppuserstohavereportedalowerrateofrecurrentanklesprainwithtimeloss.However,duetothelownumberofrecurrentinjuriesthatwerereportedandtherelativeshorttimespanoffollow-up,welackedstatisticalpowertocommentonthisresult.OnecouldspeculatethattheAppmaypromotebetterqualityexecutionoftheexercises.WheretheBookletcontainedprintedinstructionsandimagesonhowtoproperlyexecutetheexercises,theAppcontainedvideosandverbalinstructionsonthecorrectexecutionoftheexercises.Thismayhavehelpedparticipantstocorrectlyexecutetheexercises. Inarecent study among athleteswhowere ‘compliant’ with an exercise scheme, only 67%performedtheexercisesasdescribed[12].Incorrectexecutionofexercisesmaydiminishthepreventiveeffectofanexercise.Ourdataprovidethebasistostudythisquestionwithappropriatepower.

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Methodologicalconsiderations

Onecouldarguethatinpracticepatients,whoarenotinvolvedinastudy,mighthavelowercomplianceratesthatthosewereporthere.Participantswhovolunteeredtoparticipateinthestudymayalreadybeinherentlymoremotivatedtoperformtheexercises.Additionally,the weekly questionnaires used in the study allowed for a weekly reminder and thecompliancewiththeexerciseswasassessedthroughself-report.Theobligationtoreportmissedexercisesmayhaveincreasedself-reportedcompliancerates.Thisshouldbetakenintoaccountwheninterpretingthereportedcompliancerates.

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Summary

ThecurrentstudyshowedthatthemethodofimplementingtheexercisesthroughanApporaBookletdoesnotleadtodifferentcompliancerates.Bothmethodsresultedinaround75%oftheparticipantsperforminganadequatenumberofexercises.

Competinginterests

The authors declare no competing interest. VeilgheidNL has provided themobile App.However,thisAppisavailableforfree.

Contributors

EV (e.verhagen@vumc.nl) conceived the research idea, MVR (m.vanreijen@vumc.nl,@miriamvanreijen) and EV havewritten the protocol,MVR has screened and includedpatients,performeddataanalysesandisthemainauthor.IV(i.vriend@veiligheid.nl),WVM(w.vanmechelen@vumc.nl)andVZ(v.zuidema@veiligheid.nl)contributedtoideasintheprotocol.Allauthorshavereadandcommentedonthedraftversionandapprovedthefinalversionofthemanuscript.

Acknowledgements

Wewouldliketothankthefollowingpartnersfortheircollaborationandrecruitmentofstudyparticipants: RoyalDutch Society for Physical Therapy (KNGF),Dutch Society forPhysicalTherapyinSports (NVFS),DutchCollegeofGeneralPractitioners (NHG),DutchSports Medicine Society (VSG), Dutch Olympic Committee (NOC*NSF), Zilveren KruisAchmea(ZKA),andDisporta.

Patientconsent

Obtained

Ethicsapproval

The studywas approvedby themedical ethics committee of theVUUniversityMedicalCenter,Amsterdam,TheNetherlands(protocolnumber2013/248).

Funding

This study was funded by the Netherlands Organisation for Health Research andDevelopment (ZonMw) grant number 525001003, Balance boards were provided byDisportaandbookletswereprovidedbyVeiligheidNL.

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REFERENCES

1. FongDT-P,HongY,ChanL-K,YungPS-H,Chan,K-M.Asystematicreviewonankleinjuryandanklespraininsports.SportsMed2007;37:73–94.

2. VerhagenEALM,BayK,Optimizinganklesprainprevention:acriticalreviewandpracticalappraisaloftheliterature,BritishJournalofSportsMedicine2010;44:1082–1088

3. HupperetsMDW,VerhagenEALM,HeymansMW,etal,Potentialsavingsofaprogramtopreventanklesprainrecurrence:economicevaluationofarandomizedcontrolledtrial,TheAmericanJournalofSportsMedicine2010;38:2194–200

4. HupperetsMDW,VerhagenEALM,vanMechelenW,Effectofunsupervisedhomebasedproprioceptivetrainingonrecurrencesofanklesprain:randomisedcontrolledtrial,BMJ2009;339:b2684–4

5. JanssenKW,vanMechelenW,VerhagenEALM,Bracingsuperiortoneuromusculartrainingforthepreventionofself-reportedrecurrentanklesprains:athree-armrandomisedcontrolledtrial,BritishJournalofSportsMedicine2014;48:1235–9

6. VerhagenEALM,vanTulderM,vanderBeekAJ,etal,Aneconomicevaluationofaproprioceptivebalanceboardtrainingprogrammeforthepreventionofanklesprainsinvolleyball,BritishJournalofSportsMedicine2005;39:111–5

7. VerhagenE,BollingC,Protectingthehealthofthe@hlete:howonlinetechnologymayaidourcommongoaltopreventinjuryandillnessinsport,BritishJournalofSportsMedicineChangetoBrJSportsMed2015Sep;49(18):1174-8

8. VriendI,CoehoornI,VerhagenE,ImplementationofanApp-basedneuromusculartrainingprogrammetopreventanklesprains:aprocessevaluationusingtheRE-AIMFramework,BrJSportsMed.2015Apr;49(7):484-8.PublishedOnlineFirst:27January2014,doi:10,1136/bjsports-2013-092896

9. VanReijenM,VriendII,ZuidemaV,etal,Theimplementationeffectivenessofthe"Strengthenyourankle"smartphoneapplicationforthepreventionofanklesprains:designofarandomizedcontrolledtrial,BMCMusculoskeletDisord2014;15:1–8

10. VerhagenEALM,HupperetsMDW,FinchCF,etal,Theimpactofadherenceonsportsinjurypreventioneffectestimatesinrandomisedcontrolledtrials:LookingbeyondtheCONSORTstatement,JournalofScienceandMedicineinSport2011;14:287–292

11. GribblePA,DelahuntE,BleakleyC,CaulfieldB,DochertyCL,FourchetF,FongD,HertelJ,HillerC,KaminskiTW,McKeonPO,RefshaugeKM,vanderWeesP,VicenzinoB,WikstromEA.Selectioncriteriaforpatientswithchronicankleinstabilityincontrolledresearch:apositionstatementoftheInternationalAnkleConsortium.JournalofOrthopaedicinSportsandPhysicalTherapy2013Aug;43:8:585-91.

12. Fortington,LV,DonaldsonA,LathleanT,YoungWB,GabbeBJ,LloydD,FinchCF.When

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“justdoingit”isnotenough:Assessingthefidelityofplayerperformanceofaninjurypreventionexerciseprogram,Journalofscienceandmedicineinsport/SportsMedicineAustralia,2015:05:1–6

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CHAPTER5 The"Strengthenyourankle"programtopreventrecurrentinjuries.Arandomizedcontrolledtrialaimedatlong-termeffectiveness.

MiriamvanReijenIngridVriendVictorZuidemaWillemvanMechelenEvertVerhagen.JournalofScienceandMedicineinSport2017Digitalobjectidentifier(doi):10.1016/j.jsams.2016.12.001

five.

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ABSTRACT

ObjectivesRecurrentanklesprainscanbereducedbyaneuromusculartrainingprogram(NMT). Theway NMT is deliveredmay influence the incidence of long term recurrentinjuries,residualpainanddisability.

DesignThisRCTwithafollow-upoftwelvemonths,evaluatedwhethertheimplementationmethodofaproveneffectiveNMTprogramdeliveredbyamobileapplicationorawritteninstruction booklet, resulted in differences in injury incidence rates, functional ankledisability/pain in the long term, assuming equal compliance – as in shown in previousresearch-withtheeight-weekintervention.

Methods220 athleteswith a history of ankle sprainwere recruited for this RCT. 110athleteswereofferedthefreelyavailable“StrengthenyourankleApp”andtheother110received a printed Booklet. Primary outcome measure was incidence density of anklesprains. Secondary outcome measureswere residual pain/disability and the individualcumulativenumberofanklesprainsduringfollow-up.Results The incidence densities of self-reported ankle sprain recurrences were notsignificantly different between both groups (HR 1.06; 95% CI 0.76-1.49).Median FADIscoresincreasedequallyovertimeinbothgroups,indicatingalowerrateoflimitationandpain inbothgroupsat follow-up.NeitherFADIscoresnorcumulative recurrentinjuriesweresignificantlydifferentbetweengroups.ConclusionThisstudyshowedthattheimplementationmethodofaNMTprogrambyusinganApporaBookletdidneitherleadtodifferentinjuryincidenceratesinthelongtermnordiditinfluenceresidualfunctionaldisability/pain.Assumingequalcomplianceduringtheeight-weekintervention,bothmethodsshowsimilareffectivenessintwelve-monthfollow-up.

TrialregistrationTheNetherlandsNationalTrialRegisterNTR4027.TheNTRispartoftheWHOPrimaryRegistries.

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INTRODUCTION

Despite on-going societal and scientific attention, sports injuries continue to pose asubstantial health care problem. Although exercise is generally seen as contributing tooverallhealth,themanifestationofasportorphysicalactivityrelatedinjurycausesharmbothfromapersonalaswellasasocietalviewpoint[1].Theankleisthesecondmostinjuredbodypartacrossallsportsandactivities,withananklesprainbeingthemostcommonankleinjury[2].IntheNetherlandsalone,in2013,onapopulationof17million480,000peoplesufferedfromananklesprainduetosports[3].Previous studies have shown the effectiveness of neuromuscular training programs [4].Suchprogramsrequireindividualstocompleteamulti-weekexerciseprogramthatshouldbe carried out multiple times a week. Although the effectiveness of such preventiveprogramshasbeenshownincontrolledstudies,themajorityofindividualsinvolvedwereneitherablenorwillingtocomplywiththeprescribedprogram.Performingonlypartofsuchpreventiveexerciseprogramshasbeenshowntobeineffectiveinreducingtheriskofan(recurrent)anklesprain[5,6]. Inrecognitionofthemajorproblemthatanklesprainscontinue to pose for those involved in physical activities and sports, it is, therefore, ofimportancethatavailableprogramsareenhancedinsuchawaythatcompliancewiththeexerciseschemeisincreased.Inordertoincreasecompliance,itiscrucialthatthemethodofimplementationisseenasattractiveandhaslowbarriersofusetotheonesinvolved.Thechoiceofimplementationmethodmay influence both compliance and,more importantly, the recurrence of sportinjuries. A previous study has shown that during the actual course of an interventionprogram,therewasnodifferenceincompliancewhenaprintedinstructionBookletwasused when compared with a mobile application, and that during the course of theintervention program the number of recurrent injuries did not differ between bothimplementationmethods[7].However,differenceinpreventiveeffectivenessmaybeseenoveralongerfollow-upperiod,i.e.duringafollow-upperiodbeyondtheactualinterventionprogram.Consequently,theaimofthecurrentstudywastoinvestigatewhetherdeliveringaproveneffectiveneuromusculartrainingprogramthroughaBookletoranAppresultsindifferences in recurrent ankle sprain incidence over a 12-month follow-up, under thecondition of equal effectiveness and equal compliance/adherence across deliverancemethods during the actual 8 weeks intervention program. A secondary aim was toinvestigatedifferencesinpainandfunctionaloutcomesduringdailyactivitiesoverthe12monthsoffollow-up.Theanswertothesequestionsisofimportancetofurtherdevelopthemethods of delivery of the neuromuscular training program in particular and injurypreventioningeneral,whicharebotheffectiveandattractiveforthoseinvolved.

METHODS

Thisstudywasarandomisedcontrolledtrial.Adetaileddescriptionofthestudyprotocolhasbeenpublishedpreviously[8].TheMedicalEthicsCommittee(2013/248)oftheVUUniversityMedicalCenterAmsterdam(VUmc)theNetherlandsapprovedthestudydesignandinformedconsentprocedureforthisstudy.ThetrialisregisteredintheNetherlandsTrialRegistry(NTR4027).FromOctober2013 toApril2014physiotherapyandsportphysicianpractices,nationalsportfederations’websites,digitalnewslettersandsocialmediawereusedtorecruitactive

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sportsparticipants(athletes)between18and70years.Tobeincludedinthestudyathleteshadtohaveincurredaself-reportedanklesprainwithintwomonthsbeforeinclusionintothestudyandhadtohaveaccesstoamobilesmartphone(eitherAndroidoriOS).Whenrespondentshadsufferedadifferentinjuryinthesameankleintheprecedingyear(e.g.,fracture of the ankle) they were considered non-eligible. The first author assessed allreportedanklesprainsfromtheparticipantsorallytoconfirminclusioneligibility.TheflowofparticipantsisshowninFigure1.

Figure1|Flowchartofparticipantrecruitmentandfollow-up

Previoustothecurrentstudyon thelong-termeffects,astudywascarriedoutwiththesamestudysampleontheshort-termeffects.Theprimaryoutcomemeasureofthisshort-term studywas compliance to the 8-week training programme. Therefore, sample sizecalculationswerebasedupontheexpectedcomplianceratesandgroundedonpreviouslyreportedcomplianceratestothesameprogram[11].Fullcomplianceratesinthecontrolgroup(Booklet)wereexpectedtobearound25%.Adoublingofthisratetoatleast50%inthe intervention group (i.e., the App group; see below)was considered to be clinically

91

relevant.Baseduponabetaof0.90andanalphaof0.05,atotalof158athleteswasrequired,divided across both study groups. Assuming a dropout rate of 20%, a sample of 190participantswascalculated.Afterparticipantshadfinishedusualcarefortheiranklespraintreatment,andhadreturnedtheinformedconsentandbaselinequestionnaire,theywererandomlyassignedtooneoftwostudygroups;i.e.anAppgroupandawritten(print)materialsonlygroup(i.e.‘Bookletgroup). Participants were allocated to the study groups through a random numbergenerator.TheAppgroupwas instructed touse the"StrengthenyourAnkle” (inDutch:“VersterkjeEnkel”)Appontheirmobilephone,whichcouldbedownloadedforfreefromeithertheAppStore[9]ortheGooglePlaystore[10].TheBookletgroupreceivedaBookletwiththesameNMTprogramonpaper.Allparticipantsreceivedthesamebalanceboard(machU/MSGEuropeBVBA).BoththeBooklet and the App contained the same NMT program that consisted of six differentexercises to be performed during three sessions a week, for a period of eight weeks.Difficulty and load of the exerciseswere prescribed to increase every week. The NMTprogramhasbeenshowntobecost-effectiveinreducingrecurrentanklespraininprevioustrials [5,12]. The App provided the participant with an interactive exercise schedule,possibility for reminders,written instructions, and narrated video instructions on eachexercise.TheBookletusedpicturesandwritteninstructionstoexplaintheexercises.Duringtheeightweeksoftheintervention,weeklyquestionnairesweresenttoallparticipants.After theeightweeks thesequestionnairesweresentmonthly fora further tenmonths.Duringtheseten-monthfollow-upparticipantswerenolongerrequiredtofollowtheNMTprogram.Thesemonthlyquestionnairesincludedquestionsonrecurrentinjuries,exposuretosportactivitiesand,painandlimitationsasaresultoftheinitialand/orrecurrentanklesprain.ThestudyshowednodifferencesincompliancewiththeinterventionbetweentheApp-groupandtheBooklet-groupduringtheeightweeksoftheinterventionprogramme

[7].Anonlinebaselinequestionnairewasusedtocollectparticipants’informationonphysicalcharacteristics, injuryand sports history, use of preventivemeasures (tape, brace), andseverity,receivedtreatmentandrehabilitationoftheinclusionanklesprain.Theprimaryoutcomemeasureofthecurrentstudywasincidencedensityofanklesprainsasmeasuredbyself-reportduring the twelve-month follow-up. Injury incidencedensity(IID)was defined as the number of recurrent ankle sprains per 1,000 hours of sportsexposure.Duringthetwelve-monthfollow-up,participantswereaskedmonthlythroughonlinequestionnairesabouttheirhoursofsportsexposureandwhethertheyhadsustainedan ankle sprain in the previousmonth. Ankle sprain recurrencewas defined as a self-reportedinversionmomentofthesameankle,bywhichbothameremomentofinversion(givingway)aswellasclinicalanklesprainswereincluded.Self-reportedrecurrentanklesprainswerecategorizedbyseveritybylookingatrecurrencesthathadledtotime-lossorcosts.Timelosswasdefinedasthediscontinuityof(sport)activityand/ormissing(partof)thenextplanned(sports)activityduetotherecurrentanklesprain[11].Sprainsthatresultedineitherdirectorindirectcostswerecategorizedassprainsleadingtocosts.ThesemethodshavebeenusedpreviouslyintwocomparablestudieslookingattheeffectivenessoftheNMTprogramtopreventrecurrentanklesprain[6,12].SecondaryoutcomemeasurewastheFunctionalDisabilityAnkleIndex(FADI,Martin1999)[12].Thisindexhasbeenvalidatedpreviouslyandhasbeenusedtodescribepainatthe

92

ankleanddifficultyduringdailyactivities[14,15].TheFADIconsistsof26itemsscoredonafive-pointLikertscale.TheFADIwasincludedinthemonthlyquestionnaires.Theindexscorewasrecordedasapercentage.Afullscoreof104pointsresultedina100%score.ThehighertheFADI,thelowertherateof limitationandpainasaresultoftheanklesprain.Twenty-twoitemsquestionedlimitationsondailyactivities.Subjectsratedtheactivityasno difficulty at all (4 points), slight difficulty (3 points),moderate difficulty (2 points),extremedifficulty(1point),unabletodo(0points).Notapplicable(N/A)wasscoredwhentheactivitywaslimitedbysomethingotherthantheanklesprain.IfN/Awasscored,thisitemwasnot included in thefinal score.Forpainrelated itemsscoreswere:nopain (4points), mild pain (3 points), moderate pain (2 points), extreme pain (1 point) andunbearablepain(0points).Anothersecondaryoutcomemeasurewasthecumulativenumberofanklesprainsand/orinversions during the twelve months of follow-up from baseline, per participant. Thissecondary outcome measurewas calculated by adding all recurrent injuries thatweresustainedduringthetwelvemonthsoffollow-up.MeanbaselinedifferencesbetweentheAppandtheBookletgroupweredeterminedusingan independent samples t-test for continuous data (age, body weight, body height,exposure)andFisher’sexacttest(withMonteCarlo95%confidenceintervalsimulationduetosmallnumberofsamples)forcategoricaldata(levelofsport,severityofanklesprain,gender).Baselinemeasurementswerebasedonthetotalnumberofparticipants(n=220)thatwereallocatedtoeitheroneoftheinterventions.Coxregressionanalysescomparedriskofself-reported,timelossandcostrecurrentanklesprainsbetweenthegroups.Nosignificantdifferencebetweentheincidenceofrecurrentinjurieswas found. Injury incidence analyseswere checked for confounders and effectmodifiers.During the firsteightweeksof thestudy,allparticipantswerequestionedontheircompliancewiththeexerciseprogram.Performingatleast75%ofallexerciseswasregardedasbeingcompliantwiththeexerciseprogram[6].Noconfounderswerefound.Asgenderwasfoundtobeaneffectmodifierintheshortterm,separateresultswerepresentedformenandwomen[7].AMann-WhitneyUtestwasusedtocalculatethedifferencesbetweenmonthlyFADIscoresandcumulativeinjuryrecurrencesbetweenbothgroups.Allanalyseswereconductedaccordingtotheintention-to-treatprincipleanddifferenceswereconsideredsignificantwithasignificancelevelof0.05.

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RESULTS

Atotalof220athleteswasrecruitedduringtherecruitmentperiodOctober2013toApril2014.Atbaseline,bothgroupswerecomparableregardingallvariablesmeasured(Table1).

Table1Baselinecharacteristicsofthestudypopulation.Numbersarepresentedaspercentageofthepopulation

(%),themedianwithcorrespondingrangeorasthemeanwithcorrespondingstandarddeviation(mean±SD)

Combined App Booklet Pvalue

Participants(n) 220 110 110

Numberofmales(nand%) 110(50.0) 55(50.0) 55(50.0) 1.000

Age(yrs) 37.9±13.4 37.6±13.1 38.1±13.7 0.741

Weeklysportsexposure(hoursand

range)

3.0

(0-19.5)

3.0

(0-15.0)

3.0

(0-19.5)

0.791

Levelofsport(nand%)

Competitive,international

Competitive,national

Competitive,regional

Recreational,organised

Recreational,unorganised

9(4,1)

32(14,5)

76(34.5)

56(25.5)

47(42.7)

2(1.8)

19(17.3)

40(36.4)

25(22.7)

24(21.2)

7(6.3)

13(11.8)

36(32.7)

31(28.2)

23(20.9)

0.311

Contactsport(nand%) 136(61.8) 68(61.8) 68(61.8) 1.000

Severity of inclusion sprain (n and

%)

Grade1

Grade2

Grade3

Unknown

91(41.3)

64(28.9)

18(8.0)

48(21.8)

47(42.7)

34(30.9)

10(9.1)

19(17.3)

44(40.0)

30(27.3)

8(6.9)

29(26.4)

0.666

Medicallytreated(nand%) 134(61.0) 67(61.0) 65(59.0) 0.783

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Atotalof20,046hoursofsportsparticipationwasregisteredduringthe12-monthfollow-up.IntheAppgroupthetotalexposurewas9,397hours,whereasintheBookletgrouptotalexposurewas10,648hours.During12monthsfollow-up,therewere139recurrentankleinjuries:70intheAppgroupand69intheBookletgroup.Thirty-twoinjuriesledtocostsand38injuriestotimeloss.Table2showstheinjuryincidencedensitiesofallrecurrentinjuries,thoseleadingtotimelossandthoseresultingincosts.ViaCoxregressionanalysisnodifferencesininjuryincidencedensitywerefoundbetweengroups(p<0.05).

Table2Injuryincidencedensity(IID)ofself-reported,timeloss,andanklesprainrecurrencesleadingtocosts

(95%CI)per1,000hofsportsparticipation,aswellastheHazardRatio(95%CI)derivedfromCoxregression

analyses.

App Booklet

Overall n IID n IID HR

Self-reported 7015.59

(11.94-19.24)69

15.84(12.10-19.58)

1.06(0.76–1.49)

Timeloss 131.50

(0.69-2.32)25

2.71(1.65-3.77)

0.55(0.82–1.09)

Costs

16

1.96

(1.00-2.92)

16

1.85

(0.95-2.76)

1.13

(0.56–2.27)

Male 55 55 110

Self-reported 349.88

(6.56-13.20)27

8.74(5.00-12.48)

1.12(0.68-1.87)

Timeloss 81.49

(0.46-2.52)11

3.65(1.49-5.81)

0.51(0.20-1.29)

Costs 91.76

(0.61-2.9)6

1.99(0.40-3.58)

1.17(0.41-3.30)

Female 55 55 110

Self-reported 3634.25

(23.06-45.44)42

20.99(14.57-27.42)

1.09(0.70-1.72)

Timeloss 51.52

(0.19–2.85)14

2.49(1.19-3.80)

0.51(0.18-1.44)

Costs 72.30

(0.60-4.00)10

1.61(0.61-2.61)

1.04(0.39-2.77)

95

MedianFADIscoresincreasedovertimefrom92.9(62.0-100.0)atbaselineto100(57.6-100.0)at12months’follow-upintheAppgroupandfrom93.8(57.1-100.0)atbaselineto100(78.9-100.0)at12months’follow-upintheBookletgroup,respectively.Innoneofthefollow-upmonthsFADIscoresweresignificantlydifferentbetweengroups.Fromthe3rdmonth onwards, after the training programme had been completed, participantsexperiencedlittlepainandordisabilityfromtheirankleinjury.Duringthefinalmonthsofthefollow-up,painanddisabilityscoresdid,onaverage,notincrease.A total of 58 participants reportedmore than one self-reported recurrent ankle injuryduringthefollowup.TwelveparticipantsintheAppgroupand20intheBookletgroupsuffered from two ankle sprains in the 12-months follow-up; another 4 (App) and 9(Booklet)participantsrecurredthreeanklesprains,4(App)and2(Booklet)participantsdealtwith four recurrentanklesprains,and inbothgroups3participants recurred fiverecurrentanklesprains.Finally,oneparticipantintheAppgrouphadhadsixself-reportedanklesprainswithin the twelvemonths.A totalof11participants suffered two injuriesleadingtocosts;6intheAppgroupandfiveintheBookletgroup.Afurther7participantsdealtwithtwoinjuriesleadingtotimeloss,3intheAppgroupand4intheBookletgroup.Thedifferenceintotalnumberofinjuriesleadingtotimelossbetweenbothgroupsreachedsignificance(p<0.04),withnosignificantdifferencebetweenbothtotalnumberofrecurrentinjuries(p>0.58)andtotalnumberofinjuriesleadingtocosts(p<0.98).

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DISCUSSIONThe persistent existence of sport-related injuries has provided researchers and healthprofessionalswithacontinuingchallengetodevelopandimproveeffectiveinterventions

[3]. To stimulate injured athletes to comply with such interventions, the programsimplementedshouldbeattractivewithlowbarrierstouse[1].Inthepresent-daysociety,wheremobileandtabletusageisrising,E-healthisthoughttoprovidenewopportunitiestoincreasecompliancetoeffectiveinterventionprograms.Mobileapplicationsallowfornewfeatures,suchasverbalinstructions,video’sshowingthecorrectexecutionofexercisesandacalendarfunctiontoreminduserstodotheexercisesasadvised.Asourpreviousstudyhasshown,anAppdidnot lead tobettercompliance,comparedtothetraditionalwayofdeliveringaninterventionviaprintedmaterialintheshapeofaBooklet.However,thepreviousstudydidnotaddresseffectsoninjuryincidenceoveratwelve-monthperiod,asthisstudydid.Thisstudyshowed,duringthefollow-upoftwelvemonths,neitherasignificantdifferenceininjuryincidencedensitybetweenthetwogroupsnoradifferenceininjuriesleadingtocostsortimeloss.Inaddition,theFADIscoresincreasedequallyinbothgroupsduringfollow-upandreachedaceilingeffectafterthreemonths.Hereafter,painanddisabilityscoresdidnotincreaseduringtheremainderofthefollow-up. The cumulative number of recurrent injuries did not show a significantdifferencebetweentheAppandtheBookletgroup.Theseresultsdonot,byanymeans,showthattheuseofE-healthisofnouseinsportinjuryprevention.Itdoesshowthattheuseofmobileapplicationsisaseffectiveastheuseofmoretraditionalprintedinstructions.Bothmethodsofimplementationhavereceivedanupdateaftercompletingourstudy.Thisupdateaimstoincreasetheattractivenessandusabilityandthismayleadtoevenbettercompliance/adherencerates,thuspotentiallyleadingtoevenbetteroutcomes.Itispromisingthatthecomplianceinourstudywiththeinterventionshowedanincrease,ascomparedtopreviousstudieslookingatthesameneuromusculartrainingprogrambutwithanolder,simplerversionofthebooklet[5,12].Inthesestudies,compliancewiththeprogramwaslowerduringtheeightweeksofexercises–respectively23%[5]and45%oftheathleteshadhighcompliancewiththeintervention–ascomparedto65%inthestudyusingthenewmaterial[12].Withrespecttorecurrentankleinjuries,theprevioustwostudiesreportedaninjuryincidencedensityof1.86per1000hofsport;95%1.37-2.34and2.51per1000hofsport;95%1.59-3.42[5,12].Althoughtheseinjurydensitiesarevastlowerthantheonesreportedinthecurrentstudy(15.59per1000hofsport;95%11.94-19.24)fortheAppgroupand(15.58per1000hofsport;95%12.10-19.58)intheBookletgroup,thisshouldbeinterpretedasadifferenceduetoadifferenceininjury definition as the current study also included ‘givingway’ as a component of thedefinition of recurrent ankle injury. Additionally, more than half of the recurrent self-reportedinjuries(46/70intheAppgroupand47/69intheBookletgroup)inthecurrentstudyoccurredduringthefirsttwomonthsofthestudy,inwhichtheparticipantswerestillfollowingtheexerciseprogram.Thelesserhalfofallinjurieswasspreadovertheten-monthfollow-upperiod.Itisunknownhowthedistributionofrecurrentinjuriesdevelopedovertimeintheothertwostudies.Itwouldbeofgreatinteresttoseeifthesimultaneousandcombineduseofbothmethodscanfurtherincreasecomplianceandhencecontributetoeffectivesportinjuryprevention.Whenbothmethodsofimplementationcanbeusedsimultaneously,athletesinvolvedhavea diversity of means to use. This allows athletes to choose the method that is most

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convenient at a certain moment in time and/or that is in line with their personalpreferences.The results from this study can be seen as an important contribution to the scientificcommunity.WhereforthemajorityofavailableAppstheAppcontentisnotevidence-based,the“StrengthenyourAnkle”Appusesaproveneffectiveintervention[5,16].In the twelve months of follow-up, athletes were contacted monthly to assess theirrecurrent injuries and FADI scores. In the questionnaires used, they were also askedwhethertheyhadcontinuedusingtheAppand/ortheBooklet.Itispossiblethatbeingpartofthisstudyprotocolhasinfluencedtheiruseoftheintervention.Therefore,inareal-lifesituation,withoutthestimulusofthisresearch,athletesmightbelesslikelytocontinuetheexercisesandasaresultdevelopmorerecurrentinjuries.

CONCLUSION

Thisstudyshowedthatthemethodof implementingtheexercisesbyusinganApporaBookletdidnotleadtodifferentinjuryincidenceratesinthelongtermnordiditinfluenceresidual functionaldisabilityorpain.Assumingequal complianceduring theeight-weekintervention – as is shown in previous research - both methods showed similareffectivenessinatwelve-monthfollow-up.Thisindicatesthatbothmethodscanbeusedinterchangeablytoreducetheriskofrecurrentanklesprains.

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PRACTICALIMPLICATIONS

• Aproveneffectiveneuromusculartrainingprogrammecanbedeliveredbothinamobileapplicationasinaprintedinstructionbooklet.

• Both methods of implementation can be used interchangeably to reducerecurrentanklesprainsinthelongterm.

• Number of recurrent ankle injuries, residual pain/disability and cumulativenumber of recurrent ankle sprains are similar with both implementationmethods.

ACKNOWLEDGEMENTS

Wewouldliketothankthefollowingpartnersfortheircollaborationandrecruitmentofstudyparticipants: RoyalDutch Society for Physical Therapy (KNGF),Dutch Society forPhysicalTherapyinSports (NVFS),DutchCollegeofGeneralPractitioners (NHG),DutchSports Medicine Society (VSG), Dutch Olympic Committee (NOC*NSF), Zilveren KruisAchmea(ZKA),andDisporta.

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REFERENCES

1. VerhagenE,BollingC,FinchCF.Cautionthisdrugmaycauseseriousharm!Whywemustreportadverseeffectsofphysicalactivitypromotion,BrJSportsMed2015Jan;49(1):1-2

2. FongDT-P,HongY,ChanL-K,etal.Asystematicreviewonankleinjuryandanklespraininsports.SportsMed2007;37:73–94.

3. ConsumentenVeiligheid.Enkelblessuresdoorsport.Availableat:http://www.veiligheid.nl/sportblessures/kennis/cijfers-over-sportblessures.Visitedfebruary15,2016.

4. VerhagenEALM,BayK,Optimizinganklesprainprevention:acriticalreviewandpracticalappraisaloftheliterature,BrJSportsMed2010;44:1082–1088

5. HupperetsMDW,VerhagenEALM,vanMechelenW,Effectofunsupervisedhomebasedproprioceptivetrainingonrecurrencesofanklesprain:randomisedcontrolledtrial,BMJ2009;339:b2684

6. VerhagenEA,HupperetsMD,FinchCF,etal.Theimpactofadherenceonsportsinjurypreventioneffectestimatesinrandomisedcontrolledtrials:lookingbeyondtheCONSORTstatement.JSciMedSport2011;14:287–2892.

7. VanReijenM,VriendI,ZuidemaV,etal.Increasingcompliancewithneuromusculartrainingtopreventanklespraininsport:doesthe‘Strengthenyourankle’mobileAppmakeadifference?Arandomisedcontrolledtrial.BrJSportsMed.doi:10.1136/bjsports-2015-095290

8. VanReijenM,VriendI,ZuidemaV,etal,Theimplementationeffectivenessofthe"Strengthenyourankle"smartphoneapplicationforthepreventionofanklesprains:designofarandomizedcontrolledtrial,BMCMusculoskeletDisord2014;15:1–8

9. “VersterkjeenkelApp”Appstore:https://itunes.apple.com/nl/app/versterk-je-enkel/id456001033?mt=8Lastvisited:24-11-2015

10. “VersterkjeenkelApp”Googleplaystore:https://play.google.com/store/apps/details?id=nl.veiligheid.versterkjeenkel&hl=nlLastvisited24-11-2015

11. HupperetsMDW,VerhagenEALM,HeymansMW,etal,Potentialsavingsofaprogramtopreventanklesprainrecurrence:economicevaluationofarandomizedcontrolledtrial,AmJSportsMedicine2010;38:2194–200

12. JanssenKW,vanMechelenW,VerhagenEALM,Bracingsuperiortoneuromusculartrainingforthepreventionofself-reportedrecurrentanklesprains:athree-armrandomisedcontrolledtrial,BrJSportsMed2014;48:1235–1239

13. MartinRL,IrrgangJ,BurdettRG,DevelopmentoftheFootandAnkleDisabilityIndex

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(FADI)[abstract]JOrthopSportsPhysTher.1999;29:A32–A33.

14. EechauteC,VaesP,VanAerschotLetal,Theclinimetricqualitiesofpatient-assessedinstrumentsformeasuringchronicinstability:asystematicreview.BMCMusculoskeletDisord.2007;Jan;18:8:6

15. HaleSA,HertelJ.ReliabilityandsensitivityoftheFootandAnkleDisabilityIndexinsubjectswithchronicankleinstability.JAthlTrain2005,40(1):35-40.

16. VanMechelenDM,vanMechelenW,VerhagenEA.Sportsinjurypreventioninyourpocket?Preventionappsassessedagainsttheavailablescientificevidence:areview.BrJSportsMed.2014.Jun;48:11:878-882

17. BoudreauxED,WaringME,HayesRBetal.Evaluatingandselectingmobilehealthapps:strategiesforhealthcareprovidersandhealthcareorganizations.TranslBehavMed.2014.Dec:4:4:363-371

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CHAPTER6 Preventingrecurrentanklesprains:IstheuseofanAppmorecost-effectivethanaprintedBooklet?ResultsofaRCT.MiriamvanReijenIngridVriendWillemvanMechelenEvertVerhagenScandinavianJournalofMedicineandScienceinSports2017Digitalobjectidentifier(doi):10.1111/sms.12915

six.

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ABSTRACT

ObjectivesRecurrentanklesprainscanbereducedbyfollowinganeuromusculartraining(NMT)programviaaprintedBookletoramobileapplication.Regardingthehighincidenceofanklesprains,cost-effectiveness regarding implementationcanhavea largeeffectontotalsocietalcosts.Design In this economic analysiswe evaluatedwhether themethod of implementing aproveneffectiveNMTprogrambyusinganApporaBookletresultedindifferencesininjuryincidenceratesleadingtocostsandhencetodifferencesincost-effectiveness.Methods220athleteswithapreviousanklesprainwererecruited for this randomisedcontrolled trial with a follow-up of twelvemonths. Half of the athletes used the freelyavailable‘Strengthenyourankle’AppandtheotherhalfreceivedaprintedBooklet.Afterthe eight-week program athleteswere questioned monthly on their recurrent injuries.Primaryoutcomemeasureswereincidencedensityofankleinjuryandincrementalcosteffectivenessratio(ICER).ResultsDuring follow-up31athletes suffered froma recurrentanklesprain that led tocosts resulting in a Hazard Ratio of 1.13 (95% CI: 0.56-2.27). The incremental cost-effectivenessratio(ICER)oftheAppgroupincomparisonwiththeBookletgroupwas€-361.52. TheCE plane shows that therewas neither a difference in effects nor in costsbetweenbothinterventionmethods.DiscussionThisstudyshowedthatthemethodofimplementingtheNMTprogrambyusinganAppora Booklet led to similar cost effectiveness ratios and the same occurrence of recurrentinjuries leadingtocosts.BoththeAppandtheBookletcanbeusedtopreventrecurrentankleinjuries,showingnodifferencesin(cost-)effectivenessat12months’follow-up.

Trialregistration

TheNetherlandsNationalTrialRegisterNTR4027.TheNTRispartoftheWHOPrimaryRegistries.

Contributors

EV(e.verhagen@vumc.nl)conceivedtheresearchidea,MVR(m.vanreijen@vumc.nl,@miriamvanreijen) and EV havewritten the protocol,MVR has screened and includedpatients,performeddataanalysesandisthemainauthor.IV(i.vriend@vumc.nl)andWVM(w.vanmechelen@vumc.nl)contributedtoideasintheprotocol.Allauthorshavereadandcommentedonthedraftversionandapprovedthefinalversionofthemanuscript.

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INTRODUCTION

Thereisnodiscussionwhetherphysicalactivityandexercisecanbenefittheindividual.Theright sort and amount of physical activity and exercise can increase an individual’slongevity,reducetheriskofnumerousdiseasesandallowforfeelingsofjoy,friendshipandrelaxation [1-4]. There is no doubt that these individually experienced benefits alsoinfluence thewellbeing of society as awhole [5]. However, exercise does bring aboutburden and related costs to the individual aswell as society in the formof sports andexerciserelatedinjuries[6].In2013intheNetherlandsalone,atotalof4.5millionsportandexerciserelatedinjuriesoccurredonanactivepopulationof12million.Twofifthofthoseinjuries(1.9million)requiredmedicaltreatment.Itwascalculatedthatthisresultedinatotalcostof€520million[7].Anklesprainsarethemostcommonsportsandexerciserelatedinjury.Inadditiontothedirectburdenofsuchinjuries,thereisanincreasedriskofincurringrecurrentanklesprainandtheriskofchronicresidualpain[8-11].Boththehighincidenceofanklesprain,thehighriskofrecurrence,aswellastheresultingsocietalcostsjustifypreventiveefforts.Toaddressthepreventionofrecurrentankleinjuriesnumerousinterventionshavebeendeveloped. Examples of interventions are predominantly focused on using supportivematerial(e.g.tapeandbrace)andorthestrengtheningoftheanklebyexercises[12,13].Aninterventionthathasbeenshownrepeatedlytoreducerecurrentankleinjuryrisktothelevelofsomeonewhohasneversprainedhis’/herankleisaneight-weekneuromusculartraining program [14]. This program has been shaped in the ‘Strengthen your Ankle’training program and has been implemented in The Netherlands both via a printedinstructionalBookletaswellasviaamobileapplication.Previousstudieshaveshownthatbothmethodsofimplementingthisneuromusculartrainingprogramareequallyeffectivein enabling compliance with the program, as in reducing the number of self-reportedrecurrentinjuries[15,16].Althoughequallyeffectiveontheseoutcomes,cost-effectivenessmay still differ. As bothmethods require substantial development and implementationcosts,itisimportanttoevaluatewhetherthecostsandtheassociatedpreventiveeffectoftheAppandtheBooklet justifytheirwidespreaduse.Anumberofstudieshavealreadyaddressed the importance of cost-effectiveness and allow for comparisons of differentmethods. As a result, accurate analyses have been developed that determine the cost-effectivenessofthecurrentintervention[14,17].Thepresentstudyfollowsthelineofthesestudies and evaluates the cost-effectiveness of the Booklet and the App in preventingrecurrentanklesprainsovera12monthfollowup.

METHODS

This study, evaluating cost effectiveness of two methods used to implement theneuromuscular ‘Strengthen your Ankle’ program was part of a larger randomizedcontrolledtrialofwhichthedesignhasbeenpublishedbefore[18].Briefly,activesportsparticipants(athletes)whohadincurredaself-reportedanklesprainwithinthepasttwomonthswererandomizedtooneoftwostudygroupsviaarandomnumbergenerator.TheMedicalEthicsCommittee (2013/248)of theVUUniversityMedicalCenter,Amsterdam

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(VUmc)theNetherlands,hadapprovedthestudydesignandinformedconsentprocedureforthisstudy.ThetrialisregisteredintheNetherlandsTrialRegistry(NTR4027).InclusionwasheldbetweenOctober2013andApril2014viaphysiotherapyandsportsphysician practices, national sport federations’ websites, digital newsletters and openinvitationvia socialmedia, the Internetandwrittenmedia.Tobe included in thestudyactivesportsparticipants(between18and70years)hadtohavesustainedananklesprainwithinthepasttwomonthsandhadtohaveaccesstoamobilesmartphone(eitherAndroidoriOS).Whenrespondentshadsufferedanotherinjuryinthesameankleintheprecedingyear (e.g., fracture of the ankle) theywere considered non-eligible. All reported anklesprainswereassessedbyphonebythemainauthortoconfirminclusioneligibility.Theflowofparticipantscanbefoundelsewhere[18].Samplesizewasbasedoncompliancetotheeight-weektrainingprogram,whichwasthemainoutcomeoftheprimaryshort-term(i.e.duringthe8weeksofthetrial)effectivenessstudy[15].Itwasexpectedthat25%oftheparticipantswouldbefullycompliantwiththetrainingprogram.Adoublingof this complianceratewasconsideredclinically relevant.Baseduponabetaof0.90andanalphaof0.05,atotalof158athleteswasrequired,i.e.74pergroup.Previouscomparablestudieshaveshownadropoutrateduringa12months’follow-upofabout20%[14].Thismeansthatasampleof190participantswasrequiredatbaseline,i.e.95pergroup.ThestudywasapprovedbythemedicalethicscommitteeoftheVUUniversityMedicalCentre,Amsterdam,TheNetherlands(protocolnumber2013/248)andpatientconsentwasobtained.Participantsinbothgroupsreceivedthesamebalanceboard(machU,MSGEuropeBVBA)and the same neuromuscular training (NMT) program,which consisted of six differentexercisestobeperformedduringthreesessionsaweek,foraperiodofeightweeks.Theprinted instruction Booklet showed pictures of the exercises, an eight-week trainingscheduleandwritteninstructions.TheAppprovidedtheparticipantswithbothwritten,visualandverbalinstructionsandincludedacalendarfunction.TheAppgroupwasinstructedtousethe‘StrengthenyourAnkle’Appontheirmobilephone,whichcouldbedownloadedfor free fromeither theAppStoreor theGooglePlayStore[19,20].TheBookletgroupreceivedaBookletwiththesameNMTprogram,butonpaper.Bothgroupswerequestionedweekly–withonlinequestionnaires-ontheircompliancewiththeprogram,aswellasanyincurredrecurrentankleinjuriesduringthe8weeksoftheneuromuscular training program. Thereafter participants were questioned monthly onincurredrecurrentankleinjuries,foratotalfollow-upoftenmonths.Whenanathletesufferedfromarecurrentinjury,acostdiaryhadtobecompletedweeklyuntilfullrecovery.Thiscostdiaryregisteredallabsencefromstudy,schooland(un)paidwork,aswellashealthcareutilization,and thepurchaseofmedicalequipmentsuchasbraces,tapeormedication.Thismethodhasbeenusedinpreviousstudiestodeterminecost-effectivenessofthesameNMTprogramme[14,17].Ankle sprain recurrencewas defined as a self-reported inversionmoment of the sameankle,bywhichbothameremomentof inversionaswellasclinicalanklesprainswereincluded. Self-reported recurrent ankle sprainswere further categorized to severity bylooking at recurrences that led to time-loss or costs. Time loss was defined as thediscontinuityof(sport)activityand/ormissing(partof)thenextplanned(sports)activityduetotherecurrentanklesprain[21].Sprainsthatresultedineitherdirectorindirectcostswerecategorizedassprainsleadingtocosts.Thismethodhasbeenusedpreviouslyintwo

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comparablestudieslookingattheeffectivenessoftheNMTprogramtopreventrecurrentanklesprain[14,17]Atbaselineaquestionnairewassendtoallparticipantstoquestionphysicalcharacteristics,injuryandsportshistory,useofpreventivemeasures(tape,brace),andseverity,receivedtreatmentandrehabilitationoftheinclusionanklesprain.Costs related to the use of the ‘Strengthen your ankle’ App and theprinted instructionBooklet includedtheusefortheincludedmaterialcosts(thebalanceboard)andforthedevelopmentoftheApporBooklet,thetimespentconductingtheprogram(patienttimecosts),aswellasthecoststhatwereincurredduetoarecurrentanklesprain(indirectanddirecthealthcarecosts)during the twelvemonthsof follow-up.Table1shows thecostcategoriesthatwereusedinthisstudy.

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Table1|Costsappliedintheeconomicanalysis

CostoftheAppgroup(perathlete)

Balanceboard €14.00

CostperdownloadedApp €1.61

Patienttime(maximum) €168.00

CostoftheBookletgroup(perathlete)

Balanceboard €14.00

CostperprintedBooklet €0.26

Patienttime(maximum) €168.00

Directhealthcarecosts

Generalpractitioner(20minpervisit)a

€33.00

Generalpractitioner(telephoneconsult)a

€17.00

Physicaltherapist(30minpervisit)a

€33.00

Medicalspecialist(pervisit)a

€52.00

Indirecthealthcarecosts

Absenteeismfrompaidwork-men(perday)a

€37.90

Absenteeismfrompaidwork-women(perday)a

€31.60

Absenteeismfromunpaidwork(perhour)a

€14.00

a:PriceaccordingtoDutchguidelines[22]

The development costs of the App were calculated by Veiligheid.NL and included therecordingofinstructionalvideos,thecostsofdesign,thecostsforpublicationinboththeGooglePlayStoreandtheAppStoreandtestingofboththeiPhoneandAndroidversionsofthe app. Development costs were then divided by the total number of downloads asregistered inDecember 2013 (n=39,350),when follow-up of this study had ended. Thedevelopmentofthebooklet includedthecostsfordevelopment,printing,transportationandstorageofthebooklets.Thesetotalcostsaredividedbythetotalnumberofprintedbooklets(n=112,500)bytheendof2013.Patienttimewasconsideredasunpaidwork,estimatedatashadowpriceof€14,00perhour[22].Timespentonthetrainingprogramcouldbedeterminedveryaccurately,asallparticipantskeptadetailedrecordofwhichexercisestheyperformedeachweekduringthe

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eight-weekofthetrainingprogram.Fromthisitcouldbedeductedhowmuchpatienttimewasactuallyinvolved.Withfullcompliance,thecompleteprogramrequires3x30minutesofpatienttimeperweek.Associatedhealthcarecosts, standardprices forhealthcareutilizationand thecostsofmedicationandmedicalequipmentwerebasedonthepricesasrecommendedbytheRoyalDutchSocietyofPharmacy[22].Finally,costsforabsenteeismfromschool,studyand/or(un)paidworkwereincluded.Unpaidworkwasestimatedatashadowpriceof€14,00perhour,paidworkwasdeterminedbyusingthefrictionmethod.Thismethodassumesthatallworkisreplaceableandthatassociatedsocietalcostsareonlymadeduringthetimeittakes to find replacement [17]. It is recommended that the average period to findreplacement,andthustherecommendedfrictionperiod, is85days[22].Allpriceswerestandardizedtotheyear2015.Fromtheonlinequestionnaires,theinjuryincidencedensity(IID)andcorresponding95%confidenceinterval(95%CI)wascalculatedasthenumberofrecurrentanklesprainsper1,000hoursofexposure[17,23].From30ofthe31participants(97%)thathadsustainedarecurrentinjuryduringfollow-upperiod,acostdiarywasretrieved.Oneparticipantfailedtosendinformationonpossiblecoststhatweremadeaftertherecurrentinjury,althoughtheystatedtohavemadecosts.TheparticipantfromwhichdatawasmissingwasfromtheBookletgroup.Giventhelimitedamountofmissingdata,imputationtechniqueswerenotused.Tocalculate95%CIsaroundmeancosts,costdifferencesandmeanpatienttimeandpatienttime differences, nonparametric bootstrapping was used with 1,000 replications. Coxregression analyses compared risk of self-reported, time loss and cost recurrent anklesprainsbetweenbothgroups.

In addition, the Incremental Cost-Effectiveness Ratio (ICER) was calculated, using theBookletgroupasthereferencegroup[24].TheICERrepresentstheincrementalcostsofthetrainingprogramusingtheApptopreventoneanklesprainrecurrence,incomparisontotheprogramfollowedusingtheBooklet.TheICERcanbecalculatedas:(Cb-Ca)/(Eb-Ea)=DC/DE,inwhichCb=meancostsintheBookletgroup,Ca=meancostsintheAppgroup,Eb=meaneffectsintheBookletgroupandEa=meaneffectsintheAppgroup.TheuncertaintythatresultsfromthisICERwasplottedinacost-effectivenessplane,usingnonparametricbootstrapping with 1,000 replications. All analyses were conducted according to theintention-to-treatprincipleanddifferenceswereconsideredsignificantwithasignificancelevelof.05.

RESULTS

Atotalof220athleteswasrecruitedduringtherecruitmentperiodOctober2013toApril2014. At baseline, both groups had no significant differences regarding all variablesmeasured.Table2showsthebaselinecharacteristicsofthestudypopulation.

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Table2Baselinecharacteristicsofthestudypopulation.Numbersarepresentedaspercentageofthepopulation

(%),themedianwithcorrespondingrangeorasthemeanwithcorrespondingstandarddeviation(mean±SD).

Combined App Booklet

Participants(n) 220 110 110

Numberofmales(%) 110(50.0%) 55(50.0%) 55(50.0%)

Age(years) 37.9±13.4 37.6±13.1 38.1±13.7

Weeklysportsexposureatinclusion

(hours)

3.0

(0-19.5)

3.0

(0-15.0)

3.0

(0-19.5)

Contactsport(%) 61.8% 61.8% 61.8%

Severityofinclusionsprain

Grade1

Grade2

Grade3

Unknown

41.3%

28.9%

8.0%

21.8%

42.7%

30.9%

9.1%

17.3%

40.0%

27.0%

6.9%

26.1%

Medicallytreated(%) 61.0% 61.0% 61.0%

Duringthetwelve-monthfollow-upperiod,therewere139self-reportedrecurrentinjuries.Oftheseinjuries,38ledtotimeloss(13intheAppgroupand25inthebookletgroup),and31ledtocosts(16intheAppgroupand15intheBookletgroup).Table3showstheIIDofallrecurrentinjuriesduringthetwelvemonthsoffollowup,injuriesleadingtotimelossandinjuriesleadingtocosts.

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Table3InjuryIncidenceDensities(IID)andaccompanyingHazardRatiosofallself-reportedrecurrentinjuries,

injuriesleadingtotimelossandinjuriesleadingtocosts.

App

(n=110)

Booklet

(n=110)HazardRatio

Recurrentinjuries(IID)

15.59

(95%CI:11.94-

19.24)

15.84

(95%CI:12.10-

19.58)

0.94

(95%CI:0.76-1.49)

Recurrentinjuriesleadingtotimeloss

0.82

(95%CI:−0.30-

2.00)

2.36

(95%CI:0.50-

4.20)

0.55

(95%CI:0.28-1.09)

Recurrentinjuriesleadingtocosts

1.96

(95%CI:1.00-2.92)

1.85

(95%CI:0.95-2.76)

1.13

(95%CI:0.56-2.27)

Median±interquartilerangeofoveralltimespentontheexerciseprogramwas600±307minutes.IntheAppgroupthemeanoveralltimespentontheexerciseprogramwas547±278 minutes and in the Booklet group 547 ± 278 minutes. The overall time was notsignificantlydifferentbetweenbothgroups.Thetotalcostperathletewascalculatedasthesumofpatienttime,directhealthcarecostsandindirecthealthcarecosts(Table4).Therewasanoverallnon-significantcostdifferenceof€0.65perathletebetweentheAppandBookletgroup, in favourof theApp.Therewasa totalnon-significantcostdifferenceof€7.91 (95%CI€-77.95 - €85.69) per injured athlete between theApp and theBookletgroup,infavouroftheBooklet.

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Table4MeanandtotalCosts(€)perathleteandperinjuredathleteduring1-yearfollow-up.Valuesareexpressed

asmean(95%confidenceinterval).CostdifferencesarecalculatedwiththeAppgroupasthereference.

Theincrementalcost-effectivenessratio(ICER)oftheAppgroupincomparisonwiththeBookletgroupwas€-361.52,basedonadifferenceinthemeancost€-3.29andadifferenceinthemeaneffectsof1%.Thismeansthatpreventionof1anklesprainrecurrenceintheAppgroupisassociatedwith€361.52costsavingsperpreventedrecurrentanklesprain.

App Booklet Meandifference

Costsperathlete(€) n=110 n=110

Interventionmaterials €15.61 €14.26 €1.35

Patienttimecosts€123.07

(€113.29-€131.14)

€128.68

(€118.33-€138.12)

€-5.61

(€-5.15-€7.58)

Materialforrecovery

(i.e.brace,tape)

€5.41

(€1.41-€10.33)

€2.19

(€0.43-€4.31)

€3.22

(€-1.49-€8.13)

Directhealthcarecosts€11.93

(€3.67-€23.63)

€6.66

(€1.77-€12.36)

€5.27

(€-5.76-€17.43)

Indirecthealthcarecosts

(productivityloss)

€15.18

(€1.13-€38.45)

€23.04

(€0.76-€60.01)

€-7.86

(€-56.45-€27.67)

Total€171.20

(€147.15-€204.35)

€173.29

(€148.20-€212.44)

€-2.09

(€-51.32-€48.74)

Costsperinjuredathlete(€) n=70 n=69

Interventionmaterials €15.61 €14.26 €1.35

Patienttimecosts€134.78

(€125.12-€143.92)

€128.20

(€117.43-€139.00)

€6.58

(€-7.75-€20.26)

Materialforrecovery

(i.e.brace,tape)

€8.51

(€2.33-€16.05)

€3.51

(€0.80-€7.29)

€5.00

(€-2.09-€12.62)

Directhealthcarecosts€18.74

(€6.33-€36.66)

€10.68

(€2.66-€20.79)

€8.06

(€-9.98-€27.83)

Indirecthealthcarecosts

(productivityloss)

€23.86

(€1.36-€61.37)

€36.94

(€1.44-€94.59)

€-13.08

(€-95.65-€48.00)

Total€201.50

(€163.91-€257.34)

€193.59

(€154.43-€252.70)

€7.91

(€-77.95-€85.69)

111

Figure1showsthecost-effectiveness(CE)planefordifferencesintherecurrenceofanklesprainsduringthetwelvemonthsoffollow-upfortheBookletgroupversustheAppgroup.Therewasneitheradifferenceineffectsnorincostsbetweenbothinterventionmethods,as for theBookletgrouponly38%was in thedominantsoutheastquadrant (indicatingmoreeffect)and30%wasinthesouthwestquadrant(indicatinghighercosts).

Figure1Cost-effectivenessplanepresentingcost-effectpairsestimatedbyusingbootstrapping(1,000samples)

for the difference in ankle sprain recurrence risk between the App group and the Booklet group. Each dot

representsofonebootstrappedcost-effectpairthedifferenceincostsandeffectsoftheAppgroupcomparedto

the Booklet group. The outcomes of the samples are spread over the four quadrants, with only 38% of the

bootstrappedcost-effectpairsinthesouth-east‘dominant’quadrant.

In a sensitivity analysis, we calculated the ICER when the patient time costs weredisregardedfromtheanalysis.TheICERoftheBookletgroupincomparisonwiththeAppgroup,theincrementalcost-effectivenessratio(ICER)was€755.31,basedonadifferenceinthemeancostof€6,87andadifferenceinmeaneffectsof1%.Thismeansthat,whenpatient time is not taken into account, prevention of 1 ankle sprain recurrence in theBooklet group is associated with €755.31 cost savings per prevented recurrent anklesprain.Figure2showstheCEplanefordifferencesintherecurrenceofanklesprainsduringthetwelvemonthsoffollow-upfortheBookletgroupversustheAppgroup.

112

Figure2Cost-effectiveness planeafter theexclusionofpatient time, presentingcost-effectpairsestimatedby

usingbootstrapping(1,000samples)forthedifferenceinanklesprainrecurrenceriskbetweentheAppgroupand

theBookletgroup.Eachdotrepresentsofonebootstrappedcost-effectpairthedifferenceincostsandeffectsof

theAppgroupcomparedtotheBookletgroup.Theoutcomesofthesamplesarespreadoverthefourquadrants,

withonly12%ofthebootstrappedcost-effectpairsinthesouth-east‘dominant’quadrant.

DISCUSSION

Cost-effectiveness studies in sports injury preventionare rare. So far, only a handful ofstudieshasperformedsuchananalysis[14,17,25-28].The2014studybyJanssenwasthecompared two different treatment: the practice of using a brace in combination withneuromusculartrainingwascomparedtoNMTandbracingalone.Comparedtothecurrentstudy, using the same NMT programme, the patient time costs for the NMT group asreportedbyJanssenetal.2014wereconsiderablylowerduetoalowercompliancerate.Whereasonly45%ofthepatientsinthe2014studywereseenashighlycompliant,morethan70%of thepatients in thecurrent study reachedhighcompliance (i.e.performingmorethantwothirdsofallprescribedexercises).TheuseofeithertheBookletortheAppseems to bemore accepted in the sports community and the updated versions of bothmethodsarelikelymoreattractive.Thedifferenceincomplianceandhencepatienttimecostsbetween thisand the2014studyis reflected in thedifferent totalcostperathlete(€171.52inthecurrentversus€135.26forNMTgroupinthe2014study).Costsforthecombinationgroup(€163.60)weresimilarduetohighinterventioncosts(brace).TheinterventionmaterialcostsoftheAppwerebasedontheknowledgethattheAppwasdownloaded a total of 39,350 times at the time of analyses. This number is increasingsteadily,asmorepeopleareawareoftheexistenceandeffectivenessoftheApp.Andthus,with time, the intervention costs associated with the App will decrease. The costs forprintingtheBookletwillremainthesame,withnoinfluenceofthenumberprinted.The

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AppismorethantwiceasexpensiveastheBooklet,anditisnotlikelythatbothmethodswillhave thesamepriceperunit in the future.TheApphas tobedownloadedanother204,026 times to have the same price per unit as the printed Booklet. However, as adownloadedAppcanbeupdated,newprintsarenecessaryassoonasanupdatedBookletwillbeavailable.Anothermethodological consideration is that athlete compliance has steadily increasedover the last few years.NMT is nowwidely accepted as an effectivemethod to reducerecurrentanklesprains.ItislikelythatanumberofathleteshavealreadyperformedsomesortofNMTbeforeparticipatinginthisstudy.Thismightarguablereducetheinitialriskofdevelopinga(recurrent)anklesprain.

PERSPECTIVE

Thisstudyevaluatedthecost-effectivenessofaninterventiontopreventtherecurrenceofanklesprainsdeliveredthroughanAppversusthesameinterventiondeliveredthroughaBooklet.Asisshowninpreviousresearch[15,16]theuseofeithertheApportheBookletshowsimilaroutcomes,bothintheshortandinthelongrun.Notonlydidbothmethodsresultincomparablecomplianceratesduringtheeightweeksofthetrainingprogramme,bothmethods also led to comparable ankle sprain recurrence rates on the short (eightweeks)aswell as long term (one-year). Adding the results from this cost-effectivenessstudy, inwhich it was found that the costs associated with both intervention deliverymethodswerenot-significantlydifferent,itcanbearguedthatboththeAppandtheBookletcan be used successfully, andwith the same cost efficiency, to reduce recurrent anklesprains. The NMT program, in both methods of implementation, has the potential torigorouslyreducethecurrentlyhightotalsocietalcostsofanklespraintreatment.

Competinginterests

The authors declare no competing interest. VeiligheidNL has provided themobile App.However,thisAppisavailableforfree.

ACKNOWLEDGEMENTS

Wewouldliketothankthefollowingpartnersfortheircollaborationandrecruitmentofstudyparticipants: RoyalDutch Society for Physical Therapy (KNGF),Dutch Society forPhysicalTherapyinSports (NVFS),DutchCollegeofGeneralPractitioners (NHG),DutchSports Medicine Society (VSG), Dutch Olympic Committee (NOC*NSF), Zilveren KruisAchmea(ZKA),andDisporta.

114

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14. HupperetsMDW,VerhagenEALM,HeymansMW,BosmansJE,vanTulderMW,vanMechelenW.Potentialsavingsofaprogramtopreventanklesprainrecurrence:economicevaluationofarandomizedcontrolledtrial,AMJSportMed.2010:38:2194–220015. VanReijenM,VriendI,ZuidemaV,vanMechelenW,VerhagenEALM.Increasingcompliancewithneuromusculartrainingtopreventanklespraininsport:doesthe‘Strengthenyourankle’mobileAppmakeadifference?Arandomisedcontrolledtrial.BrJSportsMed.2016a:1-616. VanReijenM,VriendI.Mechelen,vanMechelenW,VerhagenEALM.The"Strengthenyourankle"programtopreventrecurrentinjuries.Arandomizedcontrolledtrialaimedatlong-termeffectiveness.JSAMS.2016b10.1016/j.jsams.2016.12.00117. JanssenKW,HendriksMRC,vanMechelenW,VerhagenEALM.Thecosteffectivenessofmeasurestopreventrecurrentanklesprains:resultsofa3-armrandomizedcontrolledtrial.AmJSportsMed.2014.Jul.42:7:1534-154118. VanReijenM,VriendI,ZuidemaV,vanMechelenW,VerhagenEALM.Theimplementationeffectivenessofthe"Strengthenyourankle"smartphoneapplicationforthepreventionofanklesprains:designofarandomizedcontrolledtrial,BMCMusculoskeletDisord2014;15:1–819. AppstoreWebsite[Internet].“StrengthenyourAnkle”app.Cited2017,June14.Availableat:https://itunes.apple.com/nl/app/versterk-je-enkel/id456001033?mt=820. GooglePlayStoreWebsite[Internet].“Strengthenyourankle”app.Cited2016March30.Availableat:https://play.google.com/store/apps/details?id=nl.veiligheid.versterkjeenkel&hl=nl21. GribblePA,DelahuntE,BleakleyCM,CaulfieldB,DochertyCL,FongDT,FourchetF,HertelJ,HillerCE,KaminskiTW,McKeonPO,RefshaugeKM,vanderWeesP,VicenzinoW,WikstromEA.Selectioncriteriaforpatientswithchronicankleinstabilityincontrolledresearch:apositionstatementoftheInternationalAnkleConsortium.JOrthopSportsPhysTher2013:43:8:585-59122. KostenhandleidingZorginstituut:Methodologievoorkostenonderzoekenreferentieprijzenvooreconomischeevaluatiesindegezondheidszorg.Nederland,201523. TwiskJWR.Basicstatisticalmethods.In:VerhagenE,MechelenWV,eds.SportsInjuryResearch.1sted.Oxford:OxfordUniversityPress;2010:19-42.�24. ChaudharyMA,StearnsSC.Estimatingconfidenceintervalsforcost-effectivenessratios:anexamplefromarandomizedtrial.Stat.Med1996:15:15:1447-1458

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CHAPTER7 Evidencebasedanklesprainpreventioninyourpocket?Amixedmethodsapproachonuser’sperspectives,opportunitiesandbarriersoftheStrengthenyourankleapp.MiriamvanReijenIngridVriendMarianneAsschemanWillemvanMechelen

EvertVerhagenJMIRRehabilitationandAssistiveTechnologies2018Digitalobjectidentifier(doi):10.2196/rehab.8638

seven.

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ABSTRACT

IntroductionThe "Strengthen your ankle” neuromuscular training (NMT)programhasbeenthoroughlystudiedinthepast8years.ThisprocessevaluationispartofaRCTthatexaminedboththeshortandlong-termeffectivenessofthisparticularprogram.Althoughitwasshownpreviouslythattheprogram–bothavailableinaprintedBookletandamobileApp-isabletoeffectivelyreducethenumberofrecurrentanklesprains,fromtheshortandlong-termstudiesitwasconcludedthatparticipants’compliancewiththeprogramisanongoingchallenge.

ObjectiveThisprocessevaluationexploredparticipants’opinionsregardingbothmethodsof delivery, using the RE-AIM (Reach Effectiveness Adaptation ImplementationMaintenance) Framework to be able to identify barriers and challenges to programcompliance.WhileReach,EffectivenessandAdaptationwheresubjectofpreviousstudy,thispaperfocussesontheImplementationandMaintenancephase.

Methods Semi-structured interviews and online questionnaires were analysed usingqualitative content analysis. Fisher’s exact, χ2 and t-tests assessed differences inquantitative survey responses among groups. Interviews were assessed by thematicanalysiswhichidentifiedkeythemes.

ResultsWhilsttherewasnosignificantdifferenceinperceivedsimplicity,usefulnessandliking of the exercise during the eight weeks of the NMT program, semi-structuredinterviews showed that 14/16 participants agreed that an Appwould be of additionalbenefitoveraBooklet.Aftertwelvemonths’follow-up,whenaskedhowtheyevaluatedtheoveralluseoftheApportheBooklet,usersoftheAppgaveameanscoreof(mean±sd)7.7±0.99versusameanscoreof7.1±1.23fortheusersoftheBooklet.Thisdifferenceinmeanscorewassignificant(p=0.006).

ConclusionsAlthoughboththeAppandtheBookletshowhighusersatisfaction,usersoftheAppweresignificantlymoresatisfied.Semi-structuredquestionnairesalloweduserstoaddress issues theywould like to improve in future updates. Including a possibility forfeedbackandpostponementofexercises,anexplanationoftheuseofspecificexercisesandpossiblymusiccanfurtherimprovethecontentmentoftheprogramandhencemightleadtoincreasedcompliance.

Trialregistration

TheNetherlandsNationalTrialRegisterNTR4027.TheNTRispartoftheWHOPrimaryRegistries.

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INTRODUCTION

Injuries,duetoparticipationinsportsandphysicalactivities,areprevalent.Internationally,anklesprainsareoneofthemostcommonmusculoskeletalinjuries[1].Inparticular,indoorandcourtsportshaveshownhighincidencesofanklesprainswithupto7injuriesper1000hours of participation [2]. Generally considered a “minor” injury, ankle sprains pose asignificantriskforlong-termsecondarycomplaintslikeinstabilityandchronicpain[3].Forthe prevention of acute lateral ankle sprains, numerous effective strategies have beendevelopedandevaluatedfortheircost-effectiveness[2].

One of themanyavailable interventions that hasbeenshown to beeffective inreducing the risk of recurrent ankle sprains, as well as protecting against secondarycomplaints, is neuromuscular training (NMT) [3-5].Multiple variations of such trainingprograms have been evaluated [6-8], including the “Strengthen Your Ankle” program(NMT).The“StrengthenYourAnkle”programconsistsof6exercisesthatareperformed3timesaweek,over8weeks.Multipletrialshaveindicatedthatthisprogramcanbeeffectivein reducing the injury incidence density [9,10] as well as being cost-effective [10,11].Despitetheprovenvalueoftheprograminpreventingrecurrentinjuryrisk,compliancewiththisandotherNMTprogramsisanongoingchallenge[3].SufficientcompliancewithNMTprogramsisessentialforsuccessfulpreventionofanklesprains[12].Consequently,afreemobileAppwasdevelopedasanovelandattractivemeansofprovidingathleteswiththe “Strengthen Your Ankle” program [13]. Details of the App have been describedelsewhere[3].Arecenttrial(NTR4027)showedthattheAppneitherincreasedcompliancenor decreased recurrence of ankle sprains compared with a standard programadministeredviaapaperBooklet[3,4,13].

Aswithotherpreventiveinterventions, the translationof theevidenceonanklesprainpreventionthroughNMTtothereal-worldcontextofsportsremainsachallenge,bywhicheffectiveanklesprainpreventioninthecommunityis lagging[14].ThesuccessofintroducinganyinterventionstrategyinapracticalcontextcanbeevaluatedusingtheRE-AIMframework[15].RE-AIMisaconceptualframeworkthatwasoriginallyusedtodevelopandevaluatehealthcareprograms.Thegoalof theRE-AIM framework is to “encourageprogramplanners,evaluators,readersofjournalarticles,funders,andpolicymakerstopaymoreattentiontoessentialprogramelements,includingexternalvalidity,thatcanimprovethesustainableadoptionand implementationofeffective,generalizable,evidence-basedinterventions”[16].

Althoughdevelopedforuseinhealthcaresettings,theRE-AIMframeworkhasbeenpreviously used to evaluate the success of introducing strategies for sports injurypreventionwithinapracticalsportscontext[17,18].Consequently,usingthecomponentsoftheRE-AIMframework,thisstudydescribedtheuserexperienceofthe“StrengthenYourAnkle”Appandbooklet tounderstandwhycompliancewaschallengedduringprogramimplementation.

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METHODS

DesignandParticipants The full details of the “Strengthen Your Ankle” study have been described elsewhere[3,4,13].Inbrief,220sportsparticipantswhoexperiencedananklesprainduringthepast2monthswereincludedinthisRCT.ParticipantswererandomlyassignedtoeithertheAppor Booklet intervention group and were instructed to follow the embedded 8-week“Strengthen Your Ankle”NMT prevention program using either the App or the printedBooklet.OutcomeMeasures TheRE-AIMframeworkdescribesfivedimensionstoevaluatethepracticalfeasibilityofanintervention: “Reach,” “Effectiveness,” “Adoption,” “Implementation,” and “Maintenance”[16]. The dimensions “Reach” and “Adoption” are out of scope when describing thefeasibilityofaninterventionwithinacontrolledtrial.Assuch,forthisstudy,wefocusedonthedimensions“Effectiveness,”“Implementation,”and“Maintenance.” Effectiveness The“Effectiveness”dimensiondescribestheclinicalimpactofthestudiedintervention.Theshort-andlong-termeffectivenessoftheAppcomparedwiththeBookletforpreventinganklesprainrecurrenceswereassessedinaRCT.Thefullmethodsandresultsofthistrialhave been published elsewhere [3,4,13]. In order to put the outcomes of the“Implementation”and“Maintenance”dimensionsincontext,wewillbrieflysummarizethe“Effectiveness”outcomes. Implementation Implementationconcernstheparticipants’useoftheinterventionstrategies.Inthisstudy,wequantifieduseascompliancewiththe8-weekNMTprogramineachofthestudygroups,measuredasapercentageof the totalprogramcompleted. Inaddition, theparticipants’attitudesandperceptionstowardthedeliveryoftheNMTprogramswereassessed.

During the8weeksof theNMTprogram,participants receivedaweeklyonlinequestionnaire.Thequestionnaireregisteredwhatpercentageoftheprogramwasexecutedduringtheweek,theamountofdifficultythatwasexperiencedwhileconductingeachoftheexercises, and the reason for a possible lack of compliance. For each of the 6 differentexercises, participants indicatedwhat percentage of the exercises they performed eachweek.Additionally,usinga5-pointLikertscale,participantswereaskedhowtheyperceivedtheexercises.Whenparticipantsfailedtocompletethequestionnaire,remindersweresentbyemail.Thedetailsonthequestionnairehavebeenpublishedpreviously[3].

Afterthe8-weektrainingperiod,amoreextensiveevaluationquestionnairewascompleted,includingclosedandfree-textquestionsonthesubjectively-experiencedvalue

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of the NMT program delivery mode, a subjective evaluation of the program, and theperceiveddisadvantagesandadvantagesoftheallocatedinterventiondeliverymode.Tomeasuresatisfaction,allremainingparticipants(75intheAppgroupand88intheBookletgroup)wereasked to givea 0-10 score for theApp orBooklet.An unpaired t testwasperformedtoexaminethedifferenceinscoresbetweenthetwogroups.Maintenance“Maintenance”describesthelong-termeffectivenessoftheinterventionstrategies.Forthisstudy, thisdimensionwasdefinedas thepercentageofparticipants still conducting theNMTprogramcombinedwiththeadvantagestheparticipantsperceivedrelatedtotheApporpaperBookletuseforinterventiondelivery.

After 12 months, semistructured interviews were conducted with individualparticipantstoassesstheperceivedadvantagesofusingtheAppoverthepaperBooklet.Allstudy participants were asked if they were willing to participate in a semistructuredinterview concerning the NMT program; 27% (32/119) of the remaining participants,evenly divided over the two study groups, responded positively. The interviews werestructured using a preselected topic list on the individual experiences with the NMTprogrameitherthroughtheBookletorApp.Allinterviewswereconductedandtranscribedby one researcher (MA). Interviewswere conducted via telephoneuntil saturationwasreached,thatis,wheninterviewsdidnotleadtonewthemesorinformation,withinbothstudy groups, resulting in 16 semistructured interviews with 8 randomly selectedparticipantsintheBookletgroupand8randomlyselectedparticipantsintheAppgroup.MultimediaAppendix1showsthequestionguideforthesemistructuredinterviews,aimedatprocessevaluation,afterfinishingthe12-monthintervention.DataAnalysesDuetodropoutduringfollow-up(n=57after8weeksandafurthern=44after12months),samplesizesdifferedbetweenquestionnaires.Thereasonsfordropoutwereunknown.Theparticipants’ answers on the 5-point Likert scales regarding attitudes and perceptionstoward theprogram,as registeredduring the8-weekprogram,wereaveraged foreachparticipant over the available follow-up moments. Independent sample t tests withassumedequalvarianceswereconducted toassess fordifferencesin theaverageLikertresponsesbetween the twostudygroups.Thesignificance levelwasevaluatedatP=.05.SPSS(version22.0)andwasusedforallstatisticalanalyses.

All semistructured interviewswereaudiorecordedandtranscribedverbatim. Intranscriptions,anypersonalinformationorinformationthatwasdeducibletoanindividualwas anonymized. Verbatim-transcribed interviews were thematically analyzed andfragmentedonthebasisoftopicalsimilarityusingAtlas.ti[19].Open,inductivecodingwasusedlinebylineonthetranscriptsoftheinterviewsandthesecodeswereconvergedintosubthemes[20].Peerdebriefingwasusedasanexternalchecktotheresearchprocess.Thismethodofanalysiswasusedaftereachinterviewandendedwhennonewcodesaroseandsaturationwasreached[19].Thefinalstepintheanalysisprocesswastosubmergethesubthemestoalimitednumberofmainthemes[19].

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RESULTS

Effectiveness Previousstudiesthatlookedattheeffectivenessofthe“StrengthenYourAnkle”programprovidedfurtherdetailsonthe(cost)-effectivenessoftheprogramintheshortandlongterm[3,4].Inshort,duringthe8weeksoftheNMT,therewere93self-reportedrecurrentanklesprains,whichresultedininjuryincidencedensitiesof25.3per1000hoursofsport(95%CI18.0to32.7)intheAppgroupand25.6per1000hoursofsport(95%CI18.3to32.9)intheBookletgroup.Therewasnosignificantdifferenceintheincidencedensitiesofself-reportedrecurrences(HR[hazardratio]3.07;95%CI0.62to15.20)[1].

Duringthe12-monthfollow-up,therewere139recurrentankleinjuries,resultingininjuryincidencedensitiesof15.59per1000hoursofsport(95%CI11.94to19.24)intheAppgroupand15.84(95%12.10to19.58)intheBookletgroup.Overthelongterm,thisdifferenceininjurydensitywasnotsignificant(HR1.06;0.76to1.49)[4].ImplementationThefirststudyinthislargerresearchprojectlookedatcomplianceduringthe8weeksoftheNMTintervention.Itwasshownthattheaveragecompliancetotheexerciseschemewas73.3%(95%CI67.7%to78.1%)intheAppgroupand76.7%(95%CI71.9to82.3%)intheBookletgroup.Nosignificantdifferenceincompliancewasfoundbetweenthegroups[3].

Theweeklyquestionnaires(Table1)showedthatparticipantsinboththeAppandBooklet groups gave comparable scores with regard to simplicity, usefulness, andsubjective evaluation of the exercises. Table 1 shows the averaged responses of theparticipantsoverthe8weeks.

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Table1.Participants’attitudesandperceptionstowardtheallocateddeliveryoftheNMTprogramduringthe8-

weekinterventionperiod.

Participants’opinions Methodof

delivery

Average

(SDa)Meandifferenceb

(95%CI)Pvalue

Theexercisesaresimple.

1. App 3.79(0.86) 0.03(−0.19to0.25) .79

Booklet 3.76(0.78)

DuetothevariationinexercisesIstaymotivated.

2. App 2.25(0.82) −0.16(−0.36to0.05) .13

Booklet 2.41(0.71)

Ifinditeasytoexecutetheexerciseswithouthelp.

3. App 3.72(0.85) 0.05(−0.16to0.26) .65

Booklet 3.67(0.75)

Theexercisesgivemeasenseofsecurity.

4. App 3.30(0.94) −0.01(−0.25to0.23) .96

Booklet 3.30(0.87)

Theexercisesarepainful.

App 3.94(0.68) −0.04(−0.22to0.14) .64

Booklet 3.98(0.67)

Theexercisesdon’tfitwithmyregularschedule.5. App 3.42(0.87) 0.09(−0.14to0.32) .47

Booklet 3.33(0.88)

Ihavetoolittletimetodotheexercises.

App 3.29(0.99) −0.09(−0.35to0.17) .49

Booklet 3.38(0.97)

Ithinktheexercisestakealongtime.

App 2.00(0.58) −0.15(−0.32to−0.01) .07

Booklet 2.16(0.67)

Theexercisesmakemetired.

App 3.87(0.75) −0.02(−0.21to0.17) .84

Booklet 3.89(0.66)

Iforgettoexecutetheexercises.

App 2.34(0.68) −0.06(−0.24to0.11) .49

Booklet 2.41(0.64)

Theexercisesarenotusefultopreventarecurrentinjury.

App 3.42(0.88) 0.12(−0.11to0.35) .32

Booklet 3.31(0.84)

Theexerciseswon’thelpme.

App 2.66(0.77) 0.07(−0.13to0.26) .50

Booklet 2.59(0.71)

aScorespresentaverages(SD)of5-pointLikertscales(1=stronglyagree;5=stronglydisagree).

bDifferencesinscoresbetweengroupswereanalyzedbyindependentttestswithequalvariancesassumed.

Afterthe8-weekinterventionperiod,35participantsusingtheAppand22participantsusingtheBookletdiscontinuedthestudyforunknownreasons.Theremaining75usersoftheAppfoundthismethodofNMTprogramdeliverymoreuserfriendly,easier,funtouse,

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andlessannoyingandthoughtthatthevideosweremorehelpfulthantheBooklet(Table2). The latter question should be interpretedwith caution because online videoswereavailablefortheBookletusers(n=88),butmanyoftheparticipantsstatedthattheywerenot aware of this possibility. Therefore, the answers of 53 of the Booklet users were“neutral”whenaskediftheonlinevideoswereofhelp;thiswasincomparisonwith5%(4/75)intheAppgroup.Someparticipantsfailedtoanswerallthequestions,thenumberofmissingresponsescanbefoundinTable2.AdditionalquestionsspecificallyrelatedtopossibleimprovementsintheApp,andnottheBooklet,(MultimediaAppendix2)indicatedthatparticipantsdesiredfeedbackaftertheexercises(44/75,59%)andwantedtheabilitytopostponeatrainingsession(41/75,55%).Overall,attestshowedthattheusersoftheAppweresignificantlymoresatisfiedwiththeApp(score1outof10with10referringtothehighestscore,mean±SD)comparedwithBookletusers;7.7(SD0.99)versus7.1(SD1.23)P=.006.

Table2.Thesubjectively-experiencedvalueoftheNMTprogramandperceiveddisadvantagesandadvantages

oftheallocatedinterventiondeliverymodeassesseddirectlyafterthe8-weekintervention.

Participants’opinions Method

of

delivery

Average

(SDa)Meandifferenceb

(95%CI)Pvalue

Theinterventionisuserfriendly.

App 1.85(0.98) −0.43(−0.75to−0.11) .009

Booklet 2.28(1.10)

Theinterventioniseasytouse.

App 1.84(0.92) −0.40(−0.69to−0.11) .008

Booklet 2.24(0.97)

Theinterventionlooksattractive.

App 2.12(0.90) −0.06(−0.35to0.23) .68

Booklet 2.18(0.97

Navigationoftheinterventionisclear.

App 2.13(0.95) −0.29(−0.59to0.01) .06

Booklet 2.42(1.01)

Theinterventiongivesenoughinformation.

App 2.19(0.95) −0.29(−0.59to0.01) .06

Booklet 2.48(0.97)

Iwouldadviseotherstousetheintervention. App 2.08(1.03) −0.29(−0.62to0.03) .07

Booklet 2.38(1.04)

Itisannoyingtousetheintervention.

App 4.09(1.09) 0.47(0.12to0.81) .008

Booklet 3.63(1.13)

Ihaveusedtheinterventionwithpleasure.

App 2.25(0.95) −0.18(−0.48to0.12) .23

Booklet 2.44(0.97)

Thevideoshelpedme(onlinefortheBooklet).

App 1.96(1.07) −0.99(−1.31to−0.68) <.001

Booklet 2.95(0.96)

125

Thewritteninstructionshelpedme.

App 2.08(0.98) −0.07(−0.35to0.21) .64

Booklet 2.15(0.84)

Theschedulehelpedme.

App 2.12(1.10) 0.08(−0.23to0.38) .62

Booklet 2.05(0.87)

Theinterventionisboring.

App 3.48(1.03) −0.05(−0.36to0.26) .73

Booklet 3.53(0.97)

Theinterventionmakesiteasiertodotheexercises.

App 2.09(0.94) −0.36(−0.65to−0.07) .02

Booklet 2.45(0.95)

Theinterventionmakesitfuntodotheexercises.

App 2.68(0.94) −0.37(−0.66to−0.08) .01

Booklet 3.06(0.93)

Theinterventionisinformative.

App 2.20(0.74) −0.14(−0.39to0.11) 0.26

Booklet 2.34(0.84)

Theinterventionistrustworthy.

App 2.23(0.84) −0.17(−0.42to0.09) 0.13

Booklet 2.40(0.870)

Theexplanationoftheexercisesisclear.

App 2.26(1.07) −0.22(−0.52to0.10) 0.17

Booklet 2.47(0.91)

aScorespresentaverages(SD)of5-pointLikertscales(1=stronglyagree;5=stronglydisagree).

bDifferencesinscoresbetweengroupswereanalyzedthroughindependentttestswithequalvariancesassumed.

Maintenance Attheendofthe12-monthfollow-upperiod,anadditional44participantsdiscontinuedthestudy.Theseparticipantswereaskediftheywerestilldoing(partofthe)NMTprogram.Only23%(28/122)ofallparticipantsstillinthestudyrespondedaffirmatively.Wedidnotaskwhatamountoftheprogramtheywerestilldoing.

Twomain themesarose from the semistructured interviews that related to thedesign of the App and possible additional benefits of the App. Fourteen out of 16participants stated that an App would provide an additional benefit compared with aBooklet.ThemainreasonsgivenwerethatmostoftheparticipantsalwayshadtheirmobilephoneswiththemandthattheAppprovidedvisualsupportandhadareminderfunction.ThetwoparticipantswhodidnotfeelthattheAppofferedanybenefitfoundtheexercisestooeasy,whichmadetheAppredundant.

Errorsinnavigationandexplanation,thelackoffeedbackandmusic,andlackofexplanationofthepurposeoftheexerciseswerethemaindisadvantagesexperiencedbytheAppusers.ThegreatestperceiveddisadvantagesoftheBookletwerethebigsizewhenfolded out, small font, lack of robustness, and errors in explanation. Table 3 shows theindividual responsesduring thesemistructured interviews to illustrate theflavorof theoriginaldataanddemonstratetheprevalenceofthethemes,assuggestedbyKing[21].

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Table3.Individualresponsesfromsemistructuredinterviews.

Respondent Addedbenefit

oftheapp?

Reasongiven Pros(+)andsuggestionsfor

improvement(−)fortheapp

App

R1 Yes Youalwayshaveyour

phonewithyou

Youforgetthebooklet

+Easytouse

+Agendafunction

+Videoswithinstructions

R2 No Theexercisesaresoeasy,

youdon’tneedanapp

+Videoswithinstructions

+Tickoffdoneexercises

- R3 Yes Youalwayshaveyour

phonewithyou

Seeingtheapponmyphone

remindsyoutodothe

exercises

+Tickoffdoneexercises

−Showwhyyouneedtodoan

exercise

R4 Yes Theappgivesvisual

support

+Easytouse

+Videoswithinstructions

R5 Yes Youalwayshaveyour

phonewithyou

+Easytouse

R6 Yes Theappissmallerandthus

easiertouse

+Easiernavigation

R7 Yes Theappgivesvisual

support

Seeingtheapponmyphone

motivatesyoutodothe

exercises

+Videoswithinstructions

+Countingdownthenumberof

exercises

R8 Yes Youalwayshaveyour

phonewithyou

+Videoswithinstructions

+Tickoffdoneexercises

Booklet

R9 Yes Youalwayshaveyour

phonewithyou

−Showwhyyouneedtodoan

exercise.

+Remindertodotheexercises.

R10 No Theexercisesaresoeasy,

youdon’tneedanapp

−Stopwatchfunction

- R11 Yes Theappgivesvisual

support

−Showwhyyouneedtodoan

exercise

R12 Yes Youalwayshaveyour

phonewithyou

+Remindertodotheexercise

−Possibilitytopostponeexercises

R13 Yes Theappgivesvisual

support

+Videoswithinstructions

R14 Yes Youalwayshaveyour

phonewithyou

Seeingtheapponmyphone

wouldremindyoutodothe

exercises

−Directtranslationoftheapptoa

booklet

127

R15 Yes Youalwayshaveyour

phonewithyou

−Morevariationintheexercises

R16 Yes Anagendafunctionwould

beeasy

−Directtranslationoftheapptoa

booklet

DISCUSSION

PrincipalFindings Previous studies [3,4] have shown that using an App or a Bookletwith a special NMTprogramtoprevent recurrentanklesprainshas resulted incomparableinjurydensitiesduring both short- (8 weeks) and long-term (12 months) follow-ups and comparablecompliancerateswiththeprogram.Duringtheexecutionoftheprogramduringthefirst8weeks,theAppandBookletweregivencomparablescoresforsimplicity,usefulness,andlikingoftheexercises.Afterthe12-monthfollow-up,theusersoftheAppweresignificantlymoresatisfiedwiththeAppcomparedwiththeusersoftheBooklet.TheusersoftheAppevaluatedtheAppasmorepatientfriendly,easiertouse,andlessannoyingandthoughtthat the videoswere helpful.With the help of semistructured interviews, 14 out of 16participantsagreedthatanAppwouldbeofadditionalbenefitoveraBooklet,mainlydueto use of instructional videos, phone portability, and the agenda function. FurthersuggestionsforimprovingtheAppthatwerementionedbyvariousparticipantsweretheabilitytopostponeexercisesandtheprovisionofexercisefeedback.

Interventionsforpreventingsportinjuriesrequirehighparticipantcompliance[3]Therefore,waystoincreasecomplianceareafocusofmanyinterventionstudies[3].The“StrengthenYourAnkle”programwasdevelopedin2009.Sincethen,theprogramhasbeenstudied intensively [3,4,9-11,22]. It was shown that (1) the program was effective inreducingrecurrentanklesprainsforthosewithhighcompliance[10],(2)theuseofeithertheApporaBookletproducednonsignificantdifferences in injurydensities inboth theshort and long term [3,4], and (3) both methods had comparable cost-effectiveness ofimplementation[23].

Overtheyears,compliancewiththe“StrengthenYourAnkle”programinRCTshassteadily increased from 23% [9] to 45% [10] and 75% [3], likely as a result of annualupdates, increased acknowledgment of the usefulness of the program by the targetpopulation,andimprovementsintheprogramcontent.However,thereachofthetargetpopulationstillrequiressubstantialattention.In2011,theannualnumberofdownloadsofthe“StrengthenYourAnkle”Appreached25,781,whichcorrespondstoalowpercentage(25,781/911,576,2.6%)ofpotentialusers[18].SomestudieshavelookedattheuseofAppsininjurypreventionoverthelastdecade.WhatcanbeconcludedfromthosestudiesisthatnumerousApps seek to prevent (re)injury.However, the scientific evidence supportingtheseApp-basedprogramsisnonexistentorscarce[22,24].Arecentreviewfoundthatoutof18appsconcernedwithpreventingsportsandphysicalactivity-relatedinjuries,onlyfourincludedevidenceregardingefficacy[22].InadditiontotheAppthat isthefocusofthisstudy,oneofthosefourappsdealtwithankleinjurypreventionusingNMT.NoinformationisavailableontheuseorcomplianceoftheotherApp[22].

ThisstudyaimedtoexploreuserexperienceswiththeNMTprogram,aswellaswiththeAppandBookletasdeliverymethods,bymeansofsemistructuredinterviews.The

128

informationgatheredcanbeusedtofurtherimprovethemethodsofdeliveryand,thus,increasefuturereachandcompliance.TheinterviewsandquestionnairesshowedthattheAppandBookletcanbesuccessfullyusedtopreventrecurrentanklesprainsandthatbothshow high user satisfaction. Future updates may include options for feedback orpostponement ofexercises, anexplanation of the use of specificexercises,andpossiblymusic;theseadditionscouldfurtherimproveuserperceptionsoftheprogramandhenceincreasecompliance.

A limitation of this study,and that of previous studieson the “StrengthenYourAnkle” program, is the mismatch between compliance and adherence. Although bothconstructshavebeenusedinterchangeably,theyarenotsynonymous.Adherencereferstoa situationwhereaclinicianor researcherdevelopsa program incooperationwith theparticipant. The participant attempts to follow the program as best as possible, takingpersonalpreferencesandconstraints intoconsideration.Adherencecanbeseenaswhathappens in real-life conditionswhen individualswith an ankle sprain try to follow theprogram; compliance is studied in clinical settings. The extent towhich the participantobeystheprograminstructionsismeasuredbycompliancerates[12,24].Research,ideallyperformedinamoreorlesscontrolledsetting,implicitlyfocusesoncompliance,ratherthanon adherence. However, the “Strengthen Your Ankle” program is meant to increaseadherenceforallindividualsatriskforananklesprain,notonlyforthosewhoparticipateinthestudiesinvolved.ThisstudyhastriedtoexplorethebarriersandopportunitiesthatparticipantsexperiencedwhileusingthetrainingprogramviaanApporBookletwithinacontrolledstudysetting.However,becausetheinterviewswereheldafterfollow-up,thatis,months after the participants had finished the 8weeks of the training program,weexpectedtogaininsightastoprogramperformanceinreal-lifesituations.

A further limitation of this study is the possibility of selection bias for thesemistructuredinterviews.Itispossiblethatonlythoseparticipantsthatcarriedastrongnegativeorpositiveviewoftheprogramagreedtoparticipatebecausetheinvitationfortheinterviewswasmadeonlyafterterminationofthe12-monthfollow-up.Additionally,the(single) interviewer did not structure the interviews and continued to question theparticipants when needed. This may have affected the validity of the data analyses.However, it is recognized that this characteristic is inherent to the flexible nature ofthematicanalysisanddoesnotthreatenthedepthofanalysis[5].ConclusionsWith the use of semistructured interviews and online questionnaires, wewere able toevaluate users’ opinions on both the App and Booklet. The users of the App weresignificantlymoresatisfiedwiththeAppalthoughtherewasnosignificantdifferenceintheperceivedsimplicity,usefulness,andlikingoftheexerciseduringthe8weeksoftheNMTprogram. In the interviews, users acknowledged the need for improvements. Futureupdatesshouldtaketheusers’suggestionsintoaccountbecauseadherencewiththeNMTprogramremainsanongoingchallenge.

ACKNOWLEDGEMENTS

This study was funded by the Netherlands Organisation for Health Research andDevelopment (ZonMw) grant number 525001003, Balance boards were provided byDisportaandBookletswereprovidedbyVeiligheidNL.

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We would like to thank the following partners for their collaboration andrecruitmentofstudyparticipants:RoyalDutchSocietyforPhysicalTherapy(KNGF),DutchSociety for Physical Therapy in Sports (NVFS), Dutch College of General Practitioners(NHG), Dutch Sports Medicine Society (VSG), Dutch Olympic Committee (NOC*NSF),ZilverenKruisAchmea(ZKA),andDisporta.ConflictsofInterestNonedeclared.

Abbreviations

ESSM: exercisescienceandsportsmedicineHR:hazardratioNMT:neuromusculartrainingRCT: randomizedcontrolledtrialZKA: ZilverenKruisAchmea

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5. VerhagenEALM,BayK.Optimizinganklesprainprevention:a critical reviewandpractical appraisal of the literature, British Journal of Sports Medicine2010;44:1082–1088

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MultimediaAppendix1:Questionguidefortheprocessevaluationusingsemi-structuredinterviewsafter

finishingthe12months’interventionperiod.

QuestionguidefortheApp

ItistruethatyouhaveusedtheApptofollowtheStrengthenyourankletrainingprogram?

Didyouexecutethe8weeksofthetrainingprogramasinstructed?

Ifno,whatwasthereasonfornotfollowingthetrainingprogramasinstructed?

Howmuchofthetrainingprogramdidyoufollow?

Doyoustillfollowthetrainingprogramnow?

Canyouelaborateonhowyouhaveexperienced:

- Theusability

- Theprovidedinformation

- Thedesign

HowdidtheappcontributetotheStrengthenyourankleprogram?

IftheAppwouldbeupdated,whatwouldyouliketoimprove?

Currentlytherearemanymedicalapplicationsavailable.Wouldyouonlyusetheseappswhenamedical

professionaladviceyoutodoso?

WouldyouadviceotherstousetheApptofollowtheStrengthenyourankletrainingprogram?

ArethereanyremarksyouwanttomakeconcerningtheApportheprogram?

QuestionguidefortheBooklet

ItistruethatyouhaveusedthebooklettofollowtheStrengthenyourankletrainingprogram?

Didyouexecutethe8weeksofthetrainingprogramasinstructed?

Ifno,whatwasthereasonfornotfollowingthetrainingprogramasinstructed?

Howmuchofthetrainingprogramdidyoufollow?

Doyoustillfollowthetrainingprogramnow?

Canyouelaborateonhowyouhaveexperienced:

- Theusability

- Theprovidedinformation

- Thedesign

YoumightbeawareofthefactthatthereisalsoamobileAppavailablewiththeStrengthenyourankle

program.Doyouthinktheappwouldcontributetothetrainingprogram?

Andifyes,how?

Howwouldyoulikeamobileapplicationtobedeveloped?Whatfeatureswouldyouprefer?

Currentlytherearemanymedicalapplicationsavailable.Wouldyouonlyusetheseappswhenamedical

professionaladviceyoutodoso?

WouldyouadviceotherstousetheStrengthenyourankletrainingprogram?

ArethereanyremarksyouwanttomakeconcerningthepossibilityofanApportheprogram?

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Multimedia Appendix 2: Responses to process evaluation of the neuromuscular training program after the

interventionperiod

Whatarethethreegreatest

benefitsoftheApp?

Whatarethethree

greatestdisadvantages

oftheApp?

Verbatimexamples

Visualaspects Video’sandsounds

Easytonavigate

Looksgood

Errorsinnavigation

Needtohavephoneat

hand

Nopossibilityto

postpone

“Thevideo’shelpmeto

dotheexercises

becausetheyshowme

howIshoulddothem.”

Informational

aspects

Schedule

Informationonbrace/tape

Writteninformation

Errorsinexplanation

Lackofexplanationof

purposeofexercise

“Theapphelpedme

withinformationonthe

exercises.”

Motivational

aspects

Thereminderfunction

Telephoneisalwaysathand

Lessboringtodotheexercises

Lackoffeedback

Notimerfunction

Nomusic

“Iwouldlovetoget

feedbackonwhyI

shoulddoaparticular

exerciseandwhat

exactlyI’mtraining.”

Whatarethethreegreatest

benefitsoftheBooklet

Whatarethethree

greatestdisadvantages

oftheBooklet?

Visualaspects Compact

Looksgood

Strongmaterial

Nopossibilitytoturn

pages

Bigwhenfoldedout

Smallletters

Lackofvideo’s

Notrobust

Noteasytounfold

“IfIknewhowthe

exerciseslooklikeona

videothismighthelp

metodothem

correctly.”

Informational

aspects

Schedule

Figures

Tothepoint

Informationonbrace/tape

Tooshortin

information

Difficultschedule

Errorsinexplanation

“Theschedulewasvery

clearandshowedme

whatIshoulddoat

whatmoment.”

Motivational

aspects

Easytocarry Lackoffeedback “Iwouldliketoseea

pictureofwhatmuscles

I’mtrainingandget

feedbackonhowIdo

theexercises.”

135

CHAPTER8Generaldiscussion

eight.

136

Theaimofthisthesiswastoevaluatethevalueofthe‘VersterkjeEnkel’Appascomparedto the usual practice of providing injuredathleteswith advisory printedmaterials. Thepremisewas that use of the ‘Versterk je Enkel’ Appwould increase compliance to theprescribedevidence-basedpreventiveprogramand,consequently,woulddecreaseanklesprain recurrence incidence. The findings from this study ultimately advance thedevelopmentofapracticalevidence-basedguidelineon‘howtoeffectivelyreducetheriskofanklesprainrecurrences’.Ideally,thisguidelineshoulddealwithtwoissues.First,theguideline should be evidence-based and feasible in a real-life situation. Second, theinterventionshouldbecost-effectiveforsocietyandshouldbeimplementableata largescale.Inordertodevelopsuchaguideline,thisthesisaddressedandansweredthefollowingquestions.

Howdoescomplianceaffectstudyresultsinsportsinjurystudies?

Studiesthathavebeendonepreviouslyonthe‘VersterkjeEnkel’neuromusculartrainingprogramprovideduswithclearfuturerecommendations.Itwasshownthattheprogramhad the potential to significantly reduce the risk of recurrent ankle sprains. However,ensuring compliancewith the program turned out to be a considerate and continuingchallenge. Inorder to findouthowcompliance isdealtwithinsports injurypreventionstudiesthisthesis,therefore,describesinchapter3asystematicreviewontheuseandrecognitionofcomplianceandadherenceinsport injurypreventiontrials. Itwasclearlydemonstrated that assuming that the entire study population had complied with theprescribed intervention could lead to erroneous conclusions. To further complicatematters, many different definitions of compliance have been reported in the sportsmedicineliterature[1].Also,althoughcomplianceandadherencearenotsynonymous[2,3],these constructs are being used interchangeably to describe the complete and correctfollowing of a prescribed intervention. Compliance refers to participant obedience in astudywhereaclinicianorresearcherprescribestheintervention,withlittletonorightofconsultationonbehalfoftheparticipant;compliancecanthusbedefinedas“theathletes’correct and complete following of a prescribed intervention” [2]. Adherence implies acollaborativeenvironmentinwhichaclinicianorresearcherandastudyparticipantworktogether to develop an intervention thatalignswith the participants’ opportunities andbarriers[4,5].Research,ideallyperformedinamoreorlesscontrolledsettingsuchasthecurrentstudy,thereforeimplicitlyfocusesoncompliance,ratherthanonadherence.Inthisreviewitwasfurtherconcludedthatinjurypreventionstudiesvarysignificantlyinthewaytheydefine,measureandadjustforcompliance.Whilethemajorityofincludedstudiesdomention the concept of compliance, only one-fifth of the studies gave amore detailedaccountofhowcomplianceratesinfluencedtheirstudyresults.Thestudiesthatdidaccountforcompliancedemonstratedthatthelevelofcompliancecouldhaveasignificanteffectonstudyoutcomes.Acknowledgingtheimportanceofcompliance,weensuredtoclearlydefine,measureandreportthisconceptandshowedhowcomplianceaffectedoutcomemeasures.

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DoestheuseofanAppincreasecompliancetotheprogram?

Intheshort-termeffectivenessstudy(chapter4)thisthesisexaminedwhethertheuseofthemobile ‘VersterkjeEnkel’Appincreasedcompliancetotheinterventionprogram,incomparisontoaprintedBooklet.Participantswereaskedweeklyabouttheircompliancewiththe‘VersterkjeEnkel’programandabouttherecurrenceofself-reportedankleinjury.This thesis shows that themethodof implementing the ‘Versterk jeEnkel’program, i.e.usinganAppversusaBooklet,didnotleadtosignificantdifferentmeanoverallcompliancerates. Additionally, the percentage of participants thatwas highly compliant – i.e. thosefollowingatleast70%oftheprogram,thearbitrarythresholdnecessaryfortheprogramtobeefficacious-wasnotdifferentbetweengroups.Inbothgroups,74.5%ofparticipantscompliedwiththeneuromusculartrainingprogrammeduringthe8weeksinwhichtheyparticipated in the study. The short-term study thus showed that compliance was notinfluencedbytheimplementationmethod.

BettereffectivenessoftheNMTprogramwhendeliveredbyApp?

Chapter5describedtheresultsaftercompletionoftheNMTprogram,at10monthsfollow-up.Participantswereaskedtocompleteanonlinequestionnaireattheendofeachmonthtoregisteranyrecurrentanklesprainandresidualfunctionaldisabilityorpain.InthisstudyitwasshownthattheimplementationmethodoftheNMTprogrambyeitheranApporaBookletdidneitherleadtodifferentinjuryincidenceratesat10monthsfollow-up,nortodifferences in residual functional disability or pain. From the above findings one canconcludethatwhentheparticipantiscompliantwiththeprogram,bothmethodsshowedsimilareffectivenessinreducingtheriskofrecurrentanklesprains,onboththeshortandthelongterm.

IstheNMTprogrammorecost-effectivewhendeliveredthroughanApp?

Considering that both theApp and theBooklet resulted in similar short and long-termeffectivenessandcompliance,thethesis’nextquestiondealtwithcost-effectiveness.Thecost-effectivenessstudyinchapter6thisthesisaddressedtwoquestions.Firstly,isthereadifference in direct and indirect costs during a 10-month follow-up, between groupsapplying the ‘Versterk je Enkel’ App and written materials? And secondly, is there adifferenceinanklesprainresidualcomplaints(i.e.instability,feelingofgivingway,pain,andcontinuedsportsparticipation)aftera12-monthfollow-up,betweengroupsapplyingthe ‘Versterk je Enkel’ App and written materials? Primary outcome measures of theanalysesweretheincidencedensityofankleinjuryandtheincrementalcost-effectivenessratio (ICER). It was shown that over the 10-month of follow-up, there was neither adifferenceineffects,norincostsbetweenbothinterventionmethods.Thisstudyshowed,assuch,thatthemethodofimplementingtheNMTprogramusinganApporaBookletcanbeusedtopreventrecurrentankleinjuries,showingnodifferencesin(cost-)effectivenessat12-monthfollow-up.

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Whatarethebarriersandfacilitatorsthataffectedprogramandhowcanthe‘VersterkjeEnkel’programbeimproved?From the five studies presented in this thesis one could conclude that in terms ofeffectiveness, theeffectoncompliance,and thecost-effectiveness,both theAppand theBookletcanbeusedtoreducetheriskofrecurrentankleinjury.Thisthesis’finalinquirywastofindouthowparticipantsevaluatedtheuseofbothmethodsofdelivery.InChapter7 this thesis presented a qualitative evaluation of the neuromuscular training programbasedonsemi-structuredinterviewsandopenquestionnaires.Multiple,individualbarriersand facilitators of the final userswere identified via a process evaluation. The RE-AIMframeworkwasusedtogetinsightintheadoptionandimplementationoftheprogram.Thisframeworkisseenasa‘reportingtemplate’toencouragesportsresearcherstodocumenttheir research inway thatenablespractitioners,policymakersandcommunities tousethemeffectively’ [6].Thestudydescribed inchapter7employed in-depth interviews toanalyseparticipants’valuationoftheNMTprogramwhileeitherusinganApporaprintedBooklet. The study looked at their challenges to comply with the NMT program andquestioned their opinion on possible improvements for the intervention and mode ofdelivery. There was no difference in perceived simplicity, usefulness and liking of theexercise between the program delivered through the App or the Booklet. After twelvemonths’ follow-up,usersof theAppweresignificantlymoresatisfiedwith theApp thanusersof theBookletwith theBooklet:7.7±0.99versus7.1±1.23 (P= .005).Participantsprovided us also with ideas on how the App could be improved to live up to theirexpectationsandhowtheseimprovementscouldhelpthemtoincreasetheircompliancewiththeprogram.Theinstructionalvideos,theagendafunctionandthesimplicityoftheAppwerefunctionsthatwerehighlyappreciated.Asexamplesoffurtherimprovements,afunction to postpone a training sessionwasmentioned, aswell as functions to providemusicandfeedbackonexercisesexecuted.

METHODOLOGICALCONSIDERATIONS

Eachofthechapterspresentmethodicalconsiderationsthatareuniquefortheindividualquestionsaddressed.Nonetheless,someconsiderationsareunderlyingthenatureofsportsinjuryresearchandarepresentedbelow.One of the most important limitations of our study was the regular contact with theparticipants.Our study involved220 athletes fromdifferent levels anddifferent sports.During follow-upwe regularly contacted the participants viaemail, and incase of non-responsebyphone.Thisinitialweekly(first8weeks)andlatermonthlycontactmostlikelyaffected the study results. Although it is unknown how compliance was influenced byparticipationinthisstudy,onecouldarguethattheregularcontactincreasedcompliancewith the program, as compared to a real-life situation where the participants are notrequiredtoreporthowmuchoftheprogramtheyexecuted.Inotherwords,contactingtheparticipantsmayhavecompromisedexternalvalidity.Asourmethodprovided theonlypossibilitytomeasurecompliancewiththeprogramwediddecidetodoso.Afurtherlimitationofthestudywasthehighrateofdrop-outduringthestudyprocess.During the first 12 months of follow-up, 35 participants (15.9%) dropped-out. Theirreasonsfordrop-outwerelackoftimeormotivationtocontinuetheprogram,orlackof

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time or motivation to continue the study (and replying to the weekly and monthlyquestionnaires).Itisnotknowniftheparticipantswhohaddropped-outdidordidnotfindthattheyhadbenefittedfromtheprogramandhadorhadnotenduredre-injury.Therefore,itisunknownifcompleteabsenceofdrop-outwouldhaveledtoadecreaseorincreaseofthe number of injuries. The high number of drop-outs, does showagain that, althoughparticipantswereregularlycontacted,motivationtocomplywiththeprogramremainsacomplexissue.Uniqueforthisstudyistheaccuratecalculationofcomplianceratesinthefirst8weeksoftheintervention.Theonlineweeklyquestionnairesallowedustodeterminewhatpartoftheprogramwascompletedbytheparticipantsandwhichexerciseswhereexecutedornot.Thisallowedforarobustevaluationofcomplianceratesfortheentiredurationofthe8-weekinterventionprogram.Furthermore,thesemi-structuredinterviewsprovideduswithdetailedanalysesoftheparticipants’evaluationoftheprogramaftertheyhadexperiencedthe use of it. This implies thatwe can, and should, not only include those involved indevelopinganintervention,butalsousingthefindingsforfutureupdates.A furtherstrengthof thecurrent studywas thecollaborationof important stakeholdersrightfromtheonsetofthisproject.Bydoingsotheprojectaimedtoreducethetimelagfromintroducingfindingsfromresearchtochangingguidelines,policiesandpractices[7].Witheverystepoftheprocess,nationalsportfederations,theNationalOlympicCommittee,Dutch health care insurance companies and federations for general practitioners andphysiotherapists were involved and enthusiastic to discuss our advice and findings.Additionally, this allowed us to relate our scientificmethods and findings to a real-lifesetting.Afterfinalisationofthisproject,thiscollaborationwillallowfortherealisationofanupdatedguidelineforthepreventionofrecurrentanklesprains.Viaourstakeholders,whoareinvolvedinthewritingofthisguideline,ourknowledgecanbetransferredtothosewhomaybenefitfromtheprogram.

FUTUREDIRECTIONS

Whatcanbeimprovedinfutureresearch?InvolvingstakeholdersTofurtherdevelopandimprovetheimplementationofthe‘VersterkjeEnkel’programitisimportantthattheend-usersareinvolvedfromaveryearlystartofprogramdevelopmentandthatathletesandstakeholdersidentifyeachother’spossibilitiesandbarriers.Assumingthattheresultsfromcontrolledtrialscanbeeasilytranslatedtoareal-lifesituationwouldneglecttheinfluenceofthemultipledeterminantsthatinfluencetheathletes’behavioursinvolved[6],ofteninanon-linearfashion.AsastutelyadvisedbyHanson[6]itisimportantnotonlytoensurecorrecttranslationfromresearchevidenceintopractice,butalsotoallowfora“bettertranslationofevidencefrompracticeintoresearch”,suchthatfutureresearchisbasedonamultidirectionalconversationinvolvingscientists,stakeholdersandathletes.Andalthoughtheremightbeaneedforthecontinuedexistenceoftraditionalpaper-basedformsof interventionmaterials,digitaltoolscanbeusednotonlytodeliverthespecificprogram,butalsotocollectdatafromtheathletethatcanbeusedtofurtherimprovetheinterventionprogram[8],suchthatallparticipantsarepartofeachdevelopmentphaseofanintervention.

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DealingwithcomplianceFromourreviewstudyitbecameclearthatvalidandreliabletoolstomeasureandreportcomplianceareneededandshouldbematched toauniformdefinitionofcompliance.Anumberofstudy-reportingguidelines,suchastheSTROBE(StrengtheningtheReportingofObservational Studies in Epidemiology) statement and the CONSORT (CONsolidatedStandards Of Reporting Trials) statement, recognise the importance of compliance andincludespecificitemsonthetopicintheirguideline[9,10,11].TheCONSORTstatementspecificallyaddressesthequalityofreportsofrandomisedcontrolledtrials(RCTs).Until2010,theCONSORTstatementadvocatedtheuseofITTanalysisforRCTs.ITTanalysisdoesnotincludethemeasurementofcompliancebutassumesnon-adherencetotheprescribedintervention[2].However,asmentionedintheCONSORTstatement,strictITTanalysisisoftenhardtoachievefortwomainreasons:missingoutcomesforsomeparticipantsandnon-adherencetotheprotocol.Therefore,since2010,theCONSORTstatementhasreplacedthementionofITTbytherequirementof‘‘moreinformationonretainingparticipantsintheir original assigned groups’’ [9]. As an alternative to an ITT analysis, it has beensuggestedthatper-protocol-analysis(PPA)—sometimesreferredtoas‘modifiedITT’—canbeused[2].Inthisapproach,theanalysisisperformedonlyonthoseparticipantswhohavefullycompliedwiththeprogramme.APPAcanprovideameasureofefficacyinthatitgivesthe result of a prescribed programme that is implemented exactly as the researcheroriginallydevelopedit,assumingthatnon-complianceisnotduetotheinterventionitself.The CONSORT statement argues that, in order to evaluate both efficacy (with theassumption of full compliance and no recognition of implementation barriers) andeffective-ness(thereal-lifeadoptionofanintervention),researchersshouldanalysestudyresultsusingITT,PPAandagradedcompliancemeasure[9].Thelatterreferstotheextenttowhichparticipantshavecompliedwiththeprogrammeandwhateffectthishashadontheoutcome.Whataretheimplicationsforpractice?Whileexaminingtheprogressofthe‘VersterkjeEnkel’programoverthelastdecade,itisclearthattheprogramanditsimplementationhaveevolved.Inthefirststudies,compliancewiththeprogramwasconsiderablylowerthaninthecurrentstudy.InthefirststudythatexaminedtheeffectivenessofthesameNMTprogrammeusingwrittenmaterialsonly,ratesofparticipantswhoshowedhighcompliancewereaslowas23%[12].Fouryearslater,inacomparablestudyfullcompliancewiththeprogramincreasedto45%[13].Inthecurrentstudy,thepercentageofparticipantsthatwashighlycompliantwas65%.ItwasarguedthatwithtimetheneuromusculartrainingprogrammehadbecomemorewidelyacceptedintheNetherlands.Thismightexplaintheincreaseincompliancerates.Withafurtherincreaseinthenumberofdownloadsandcampaignstosupportthe‘VersterkjeEnkel’programitispossible that theneuromuscular trainingprogrammewill show increasedacceptance inpracticeevenfurther.Inaddition,thepreviousstudiesusedaprintedpaperversion,withasimplelayout.BoththeBookletandtheAppusedinthecurrentstudywereupdatesofthematerialsthathavebeenusedinthepreviousstudies.WehypothesizethattheBookletandthe App used in our study may have had a more attractive format, which resulted inincreasedcompliancerates.However,althoughcomplianceinthecurrentstudyshowedasignificant increase compared to previous studies on the same program, to effectively

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reduce the persistent existence of sports injuries, we should continue to look forinterventionswiththelowestbarrierstouse.Ourprocessevaluationprovideduswithclearinstructionsonhowtofurtherimprovebothmethodsofimplementationsuchthattheyliveuptousers’expectationsandfurtherenhancecompliancewiththeprogram.Itisimportantthatfutureupdatestaketheserecommendationsintoaccount.Withthecollaborationofthestakeholdersinvolvedinthisresearchprocesswehopetohaveadecisiveimpactonthefutureguidelines.Allowco-existenceofinnovativeandtraditionalmethodsInthepastdecenniaavastnumberofmobileappshaveenteredthesportinjurypreventionarena.Theincreaseduseofmobilephonesinallareasofmodernlifemighthaveledtotheassumptionthatappscan,andshould,beexclusivelyusedaseffectivemethodstodeliverinjurypreventioninterventionstothoseinvolved.However,withtheuseofthein-depth-interviews,thehelpofthestakeholdersandourthoroughanalysisofcomplianceand(cost-)effectivenesswe learned from this study that there is no such thing as THE (injured)athletewithsetdeterminantsofbehaviour.Eachofthe220participantshaditsownstoryonhowthefirstanklesprainarose,ifandhowitwastreatedandhowtheindividualwentaboutpreventing(ornot)re-injury.Duringboththeshortandthelongterm,eachoftheparticipants had to find the time, the motivation and the resources to do so. Somesucceeded, somedidnotandsomeonly toa certainextent. Itbecameclear thatnotallparticipantspreferredtheuseofthemobileapp.This ledustoconcludethattraditionalmethods of delivery should not be forgotten and if possible, should co-existwithmoreinnovative,-mobile-options.Withmultipleoptions,thediversityinindividuallimitationsandbarrierscan be acknowledged. Or, as clearly stated byGreen and cited by others:“Wheredidthe(sportinjuryresearch)fieldgettheideathatevidenceofanintervention’sefficacyfromcarefullycontrolledtrialscouldbegeneralizedas ‘bestpractice’ forwidelyvariedpopulationsandsituations”[6.14,15]?

OVERALLCONCLUSIONS

Wefoundthatthemethodofimplementingdidneitherleadtodifferentratesofcompliancenortodifferencesin(cost-)effectiveness.Bothintheshortandlongterm,ratesofre-currentanklesprainweresimilarwhenusing theApp or theBooklet, andcompliancewith theprogramdidnotdifferbetweenbothmethodsduringthe8weeksoftheintervention.Ouradvicefortheindividualathleteandthestakeholdersinvolvedwouldthereforebetousethemethod that ispreferredby theathlete.This canbe theApp, theBookletorevenacombinationofboth,suchthattheathletecanchoosethemethodofimplementationthatismosteasilyaccessibleatacertainmomentoftime.Ourmainmessageisthattheprogramiseffectivebutshouldbeexecuted.

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publishedmanuscripts.ClinJSportsMed.2010;20(6):407–12.

2. VerhagenEALM,HupperetsMDW,FinchCF,etal.Theimpactofadherenceonsportsinjurypreventioneffectestimatesinrandomisedcontrolledtrials:LookingbeyondtheCONSORTstatement.JSciMedSport.2011;14(4):287–92.

3. McKayCD,VerhagenE.'Compliance'versus“adherence”insportinjuryprevention:whydefinitionmatters.BrJSportsMed2016;50:382–3.doi:10.1136/bjsports-2015-095192

4. SteffenK,EmeryCA,RomitiM,etal.Highadherencetoaneuromuscularinjurypreventionprogramme(FIFA11?)improvesfunctionalbalanceandreducesinjuryriskinCanadianyouth female football players: a cluster randomised trial. Br J Sports Med.2013;47(12):794–802.

5. SabateE.Adherencetolong-termtherapies.Geneva:WorldHealthOrganization;2003.

6. HansonD, Allegrante JP, SleetDA, FinchCF,Researchalone is not sufficient to preventsportsinjuryBrJSportsMed.2014Apr;48(8):682–684.

7. Bekker S, Paliadelis P, FinchCF. The translation of sports injury prevention and safetypromotion knowledge: insights from key intermediary organisations. Health Res PolicySyst.2017:15:25doi:1o.1186/s12961-017-0189-5

8. Finch CF, Barh R, Drezner JA, Dvorak J, Engebretsen L, Hewett T, Junge A, Khan KM,MacAuleyD,MathesonGO,McCroryP,VerhagenE.Towardsthereductionof injuryandillnessinathletes:definingourresearchpriorities10.1136/bjsports-2016-097042

9. SchulzKF,AltmanDG,MoherD.CONSORT2010statement:updatedguidelinesforreportingparallelgrouprandomisedtrials.BMCMed.2010;23(340):c332.

10. SorensenAA,WojahnRD,ManskeMC,etal.Usingthestrengtheningthereportingofobservationalstudiesinepi-demiologystatement(STROBE)toassessreportingofobservationaltrialsinhandsurgery.JHandSurgAm.2013;38(8):1584.e2–1589.e2.

11. YoonU,KnoblochK.QualityofreportinginsportsinjurypreventionabstractsaccordingtotheCONSORTandSTROBEcriteria:ananalysisoftheWorldCongressofSportsInjuryPreventionin2005and2008.BrJSportsMed.2012;46(3):202–6.

12. Hupperets MD, Verhagen EA, van Mechelen W. Effect of unsupervised home basedproprioceptivetrainingonrecurrencesofanklesprain:randomisedcontrolledtrial.BMJ2009;339:b2684–4.�

13. JanssenKW,vanMechelenW,VerhagenEA.Bracingsuperiortoneuromusculartrainingforthepreventionofself-reportedrecurrentanklesprains:athree-armrandomisedcontrolledtrial.BrJSportsMed2014;48:1235–9.�

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14. GreenL.Fromresearchto“bestpractices”inothersettingsandpopulations.AmJHealthBehav2001;35:165–78

15. ViehbeckSM,PetticrewM,CumminsS,OldMyths,NewMyths:ChallengingMythsinPublicHealthAmJPublicHealth.2015April;105(4):665–669.�

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SUMMARY

Whileexerciseisgenerallyadvocatedtocontributetooverallwell-being,itcomeswithahealthrisk,bothfortheindividual,asforsocietyasawhole.Thebodypartsthataremostoften affected by an injury are the knee and the ankle, with respectively 970.000 and680.000 injuries in the Netherlands alone. The singlemost common injury is an anklesprain,whichmakes up85%of all ankle injuries. In addition to societal costs, there isextensiveevidencethatthereisanuptotwofoldincreasedriskforanklere-injuryduringthefirst-yearpost-injury.Inabout50%ofallcasesrecurrencesmayresultindisability,canleadtochronicpainorinstabilityandmayrequireprolongedmedicalcare.Assuch,anklesprainsposeasignificantburdentotheindividualathleteandtosociety.Previous research has shown that bothexternallyappliedankle supports (i.e. taping orbracing), as well as neuromuscular training programs are successful in preventingrecurrentcasesofanklesprain,bothfromaneffectiveness,aswellasacost-effectivenessperspective.Thesemeasurescanreducetheincreasedriskofrecurrentinjurytothesamelevelasneverinjuredathletes.However,althoughtheneuromuscularprogramhasbeenproven(cost-)effectivecompliancewiththeprogramispoor.Theaimofthisthesisistoevaluatetheimplementationvalueofthe‘VersterkjeEnkel’Appascomparedtotheusualpracticeofprovidinginjuredathleteswith‘ordinary’materials.Thepremiseisthatuseofthe ‘VersterkjeEnkel’Appwouldincreasecompliancetotheprescribedprogramand,consequently,woulddecreaseanklesprainrecurrenceincidence.Chapter2–ThefoundationforallincludedpublicationsinthisthesisChapter2 describes the studydesign of the ‘Verstek je Enkel’ research line that is thefoundationforthisthesis.Itexplainsindetailhowtheparticipantshavebeenrecruitedandhowtheflowofathleterecruitmentwasexecuted.Chapter2alsoprovidesdetailsonthe‘Versterk je Enkel’ programwith visual examples of the included exercises and gradedschedule.Chapter3-DelvingintotheconceptofcomplianceAnimportantpartofthisthesisdealswiththeconceptofcompliance.Chapter3showstheresultsofextendedreviewonsportinjuryinterventionstudies.Itshowshowcomplianceisdefined,measuredanddealtwithin100RCT’s.Itwasshownthatassuminganentirestudypopulationcomplieswiththeprescribedinterventioncouldleadtoerroneousconclusions.To further complicate matters, many different definitions of compliance are used andalthoughcomplianceandadherencearenotsynonymous,theseconstructsarebeingusedinterchangeably to describe the complete and correct following of a prescribedintervention.Whilethemajorityofincludedstudiesinthereview,domentiontheconceptofcompliance,onlyone-fifthofthestudiesgaveamoredetailedaccountofhowcompliancerates influenced their study results. The studies that did account for compliancedemonstratedthatthelevelofcompliancecouldhaveasignificanteffectonstudyoutcomes.

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Chapter4-Shorttermresultsfromthe‘VersterkjeEnkel’programme

Chapter4presentstheresultsfromtheshort-termstudy.ItcomparedthecomplianceratesoftheinterventionprogramfromAppuserswiththoseusingaprintedBooklet.Participantswereaskedweeklyabouttheircompliancewiththe‘VersterkjeEnkel’programandaboutthe recurrence of self-reported ankle injury. It was shown that using an App versus aBooklet,didnot leadtosignificantdifferentmeanoverallcompliancerates.Additionally,thepercentageofparticipantsthatwashighlycompliant–i.e.thosefollowingatleast70%oftheprogram,thearbitrarythresholdnecessaryfortheprogramtobeefficacious-wasnot different between groups. Themean compliance to theexercise schemewas 73.3%(95% CI: 67.7-78.1) in the App group, compared to 76.7% (95% CI: 71.9-82.3) in theBookletgroup.Additionally,theincidencedensitiesofself-reportedtime-lossrecurrenceswerenotsignificantlydifferentbetweenbothgroups(HR3.07;95%CI0.62-15.20).

Chapter5–Longtermeffectiveness–a12-monthfollow-upAftertheinterventionprogramthatlastedfor8weeks,participantswerefollowed-upforanother10months.Theywereaskedtocompleteonlinequestionnairemonthlytoexaminere-injuryandtoregisteranyresidualfunctionaldisabilityorpain.Afterthetotaltimeframeof12months,therewerenodifferencesininjuryincidencerates(HR1.06;95%CI0.76-1.49)nordifferencesinresidualfunctionaldisabilityorpain.Itwasconcludedthatwhentheparticipantiscompliantwiththeprogram,bothmethodsshowedsimilareffectivenessinreducingtheriskofrecurrentanklesprains,onboththeshortandthelongterm.Chapter6–Whichprogramismorecost-effective?PrimaryoutcomemeasuresofChapter6weretheincidencedensityofankleinjuryandtheincrementalcost-effectivenessratio(ICER)during12monthsfollow-up.Duringfollow-up31athletessufferedfromarecurrentanklesprainthatledtocostsresultinginaHazardRatioof1.13(95%CI:0.56-2.27).Theincrementalcost-effectivenessratio(ICER)oftheAppgroup in comparisonwith theBooklet groupwas€-361.52. TheCEplane presented inchapter6showsthattherewasneitheradifferenceineffectsnorincostsbetweenbothinterventionmethods.Chapter7–AthoroughexaminationofuserexperiencesTo evaluate the ‘Versterk je Enkel’NMTprogramweused theRE-AIM frameworkas areportingtemplate.Welookedattheimplementationandmaintenancephasetoidentifythebarriersandfacilitatorsasexperiencedbythefinalusers.Semi-structuredandonlinequestionnaires showed that therewas no significant difference in perceived simplicity,usefulnessandlikingoftheexerciseduringtheeightweeksoftheNMTprogram.14/16participantsfromtheinterviewsagreedthatanAppwouldbeofadditionalbenefitoveraBooklet.Aftertwelvemonths’follow-up,whenaskedhowtheyevaluatedtheoveralluseoftheApportheBooklet,usersoftheAppgaveameanscoreof(mean±sd)7.7±0.99versus

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ameanscoreof7.1±1.23fortheusersoftheBooklet.Thisdifferenceinmeanscorewassignificant(p=0.006).

CONCLUSION

Wefoundthatthemethodofimplementingthe‘VersterkjeEnkel’NMTprogramdidneitherleadtodifferentratesofcompliancenortodifferencesin(cost-)effectiveness.Bothintheshortandlongterm,ratesofre-currentanklesprainweresimilarwhenusingtheApportheBooklet,andcompliancewiththeprogramdidnotdifferbetweenbothmethodsduringthe8weeksoftheintervention.Thesemi-structuredinterviewsandourthoroughanalysisofcomplianceand(cost-)effectivenessshowedusthatthereisnosuchthingasTHE(injured)athletewithsetdeterminantsofbehaviour.Eachofthe220participantshaditsownstoryonhowthefirstanklesprainarose,ifandhowitwastreatedandhowtheindividualwentaboutpreventing(ornot)re-injury.Duringboththeshortandthelongterm,eachoftheparticipantshadtofindthetime,themotivationandtheresourcestodoso.Somesucceeded,somedidnotandsomeonlytoacertainextent.Itbecameclearthatnotallparticipantspreferredtheuseofthemobileapp.Thisledustoconcludethattraditionalmethodsofdeliveryshouldnotbeforgottenand ifpossible, shouldco-existwithmore innovative, -mobile-options.Withmultipleoptions,thediversityinindividuallimitationsandbarrierscanbeacknowledged.Ouradvicefortheindividualathleteandstakeholdersinvolvedwouldthereforebetousethemethod that ispreferredby theathlete.This canbe theApp, theBookletorevenacombinationofboth,suchthattheathletecanchoosethemethodofimplementationthatismosteasilyaccessibleatacertainmomentoftime.Ourmainmessageisthattheprogramiseffectivebutshouldbeexecuted.

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SAMENVATTING

Hoewelbewegingensportbijkandragenaaneengoedegezondheidbrengthetookhetrisicovanblessuresmetzichmee.Blessureskunnen leiden totaanzienlijkekostenvoorzowelhetindividualsvoordegemeenschapalsgeheel.Delichaamsdelendiehetvaakstgeblesseerdrakenzijndeknieendeenkelmetjaarlijksrespectievelijk970.000en680.000blessuresinNederland.85%vandeblessuresbetrefteenverstuikingvandeenkel.Hetishiermee de meest voorkomende blessure. Naast de maatschappelijke kosten van dezeblessures,brengteeneenmaligeenkelverstuikingookeentweevoudigrisicoopherletselmetzichmeevoordegetroffeneinheteerstejaarnahetletsel.Inongeveer50%vandegevallenleidtherletseltotchronischepijn,instabiliteitofvanlangdurigeinvaliditeit.Hetmoge duidelijk zijn dat enkelletsel voor zowel de maatschappij als het individu groteproblemenmetzichmeekanbrengen.Eerder heeft onderzoek aangetoonddat hulpmiddelen (zoals tape ofeen brace) en eenneuromusculair trainingsprogramma(hetVersterk jeEnkeloefenprogramma)succesvolzijn in het voorkomen van herletsel. Dit betreft zowel het aantal herletsel als dekosteneffectiviteit van deze interventies. Personen die deze hulpmiddelen gebruikenkunnen hun risico op herletsel reduceren tot hetzelfde level als personen die nooitgeblesseerd zijn geweest. Het probleem is echter dat de therapietrouw van dezeinterventieszeerlaagis.Hetdoelvandezethesisisomdeimplementatievande‘VerstekjeEnkel’Apptevergelijkenmethetzelfdeprogrammamaardanindevormvaneengeprintboekje.Deuitkomstenvandethesiskunnenzoeenbijdragenleverenaandehuidigerichtlijnenvoorhetverminderenvanrecidiefenkelletsel.Hoofdstuk2–HetfundamentvanhetonderzoekHoofdstuk2ishetgepubliceerdeonderzoeksontwerpzoalsgepresenteerdaanhetbeginvandezeonderzoekslijn.Hetbevateengedetailleerde(visuele)uitlegvanhetprogrammaendemanierwaaropdedeelnemerszijngerekruteerd.Wemaaktenbijhetwervenvandedeelnemersuitvoeriggebruikvandekanalenvanonzeconsortiumpartners.Hoofdstuk3–TherapietrouwnaderbekekenEen belangrijk deel van deze thesis gaat over het concept therapietrouw (compliance).Hoofdstuk 3 laat de resultaten zien van een review naar therapietrouw ininterventiestudiesmetbetrekkingtotsportblessurepreventie.Hethoofdstuklaatzienhoeditconceptinmeerdan100RCT’swordtgedefinieerd,berekendengeanalyseerd.Indereviewkwamnaarvorendatdeaannamedatalledeelnemersvolledigtherapietrouwzijn,kan leiden tot onjuiste conclusies aangaande de effectiviteit van de interventie. In deonderzochtestudieswordenbovendientalvanverschillendedefinitiesvoorhetconceptgehanteerd enwordt het concept ‘adherence’ veelal onjuist gebruikt als synoniemvoortherapietrouw(compliance).Hoewelhetmerendeelvandestudieswelaandachtbesteedtaanhetconcept,geeftslechtseenvijfdedeelaanhoezetherapietrouwberekenenenhoedit invloed heeft op de studieresultaten. De studies die wel nadrukkelijk kijken naartherapietrouwlatenziendathetconceptgroteinvloedheeftopdeuiteindelijkeconclusies.

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Hoofdstuk4–DeeffectiviteitvanhetoefenprogrammaopdekortetermijnHoofdstuk4laatderesultatenzienvandestudienaardeachtwekenwaarindedeelnemershet‘VersterkjeEnkel’oefenprogrammavolgen.Indithoofdstuktonenwehetverschilintherapietrouw en zelf-gerapporteerd, recidief enkelletsel gedurende deze periode. Dedeelnemerswerdgevraagdwekelijkseenonlinevragenlijstintevullen.Welietenziendater geen significant verschil bestaat tussen therapietrouw wanneer het boekje wordtgebruiktinvergelijkingmetdemobieleApp.Ookhetverschilindeelnemersdattenminste70%vanhetprogrammauitvoerden-dearbitrairedrempeldienodigisomhetprogrammaeffectief te laten zijn – was niet verschillend tussen beide groepen. De gemiddeldetherapietrouwwas73.3%(95%CI:67.7-78.1)indeAppgroep,vergelekenmet76.7%(95%CI:71.9-82.3)indegroepdiehetboekjegebruikte.Tenslottebleekookhetvoorkomenvanrecidiefenkelletseldatleiddetottijdverliesnietverschillend(HR3.07;95%CI0.62-15.20).Hoofdstuk5-DeeffectiviteitvanhetoefenprogrammaopdelangetermijnNa het ‘Versterk je Enkel’ oefenprogramma werden de deelnemers nog 10 maandengevolgd.Indezeperiodewerdhengevraagdelkemaandeenvragenlijstintevullen.Hierinwerdgevraagdofersprakewasvanrecidiefenkelletseleninhoeverrededeelnemerslasthaddenvanrestklachten.Nadetotaleperiodevantwaalfmaandenbleekergeenverschilinhetaantalherletsels (HR1.06:95%CI0.76-1.49)ofdematewaarinsprakewasvanrestklachten.Weconcludeerdendatwanneereendeelnemervoldoendetherapietrouwisaangaande het programma, het gebruik van zowel het boekje als de App het risico openkelblessures aanzienlijk kan verkleinen. Dit geldt voor zowel de korte als de langetermijn.Hoofdstuk6–Welkprogrammalaateengroterekosteneffectiviteitzien?Deprimaireuitkomstmatenvanhoofdstuk6warenhetaantalherletselsper1000urensportendeincrementalcost-effectivenessratio(ICER)gedurendede12maandenwaarindedeelnemerswerdengevolgd.Tijdensdeopvolgingkregen31atletentemakenmetherletselwaarbij er sprake was van gemaakte kosten. Dit resulteerde in een relatief risico opherletselvan1.13(95%CI:0.56-2.27).DeICERvandeAppgroepinvergelijkingmetdegroepdiehetboekjegebruiktewas-€361,52.Hetkosten-effectiviteitsvlak,gepresenteerdinhoofdstuk6,laatziendatergeenverschilineffectiviteitofinkostenbestaattussenbeideinterventiemethodes.Hoofdstuk7–Watvondendegebruikersvandeinterventie?Met behulp van het RE-AIM kader trachtenwe te bepalenwat de deelnemers aan hetonderzoek van de interventie vonden.We kekenmet name naar de implementatie- enbehoudsfase om de barrières en bevorderende factoren in kaart te brengen zoals diewerden ervarendoor de gebruikers. Semigestructureerde en online vragenlijsten lietenzien dat er geen verschil bestond in ervaren gebruiksgemak, nut en plezier van deoefeningengedurendedeachtwekendathetprogrammaduurde.Veertienvandezestiendeelnemers die werden geïnterviewd zagen een toegevoegde waarde van de App tenopzichtevanhetboekje.Natwaalfmaanden,wanneerhengevraagdwerdnaardetotale

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evaluatie van hun gebruikte interventiemethode, gaven de gebruikers van de App eengemiddelde(±SD)scorevan7.7±0.99invergelijkingmeteen7.1±1.23metdegebruikersvanhetboekje.Hetverschilisscoreissignificant(p=0.006).

CONCLUSIE

Wekunnenconcluderendatdemethodewaarophet‘VersterkjeEnkel’oefenprogrammawordt geïmplementeerd niet leidt tot een verschil in therapietrouw of in(kosten)effectiviteit.Ditgeldtvoorzoweldeduurvanhetprogrammazelf(8weken)alstijdenseenlangereperiodevan12maanden.Zowelopdekortealsdelangetermijnlatenbeidemethodenevenveelrecidieveenkelletselszien.Desemigestructureerdeinterviewsendeanalysesvantherapietrouwenkosteneffectiviteitduiden erop dat er niet gesproken kan worden over DE (geblesseerde) atleet metvastomlijndegedragsdeterminanten.Elkvande220betrokkendeelnemerskwammetzijneigen verhaal over hoe zijn blessure is ontstaan, hoe dezewerd behandeld en hoe hetindividuzichzelfinstaatachtteherletseltevoorkomen.Zoweltijdensdekortealsdelangetermijn moesten alle deelnemers de tijd, motivatie en middelen vinden om hetoefenprogramma te volgen. Sommigen slaagden hierin, anderen niet en weer enkelenslechtsinbeperktemate.HetwerdonsduidelijkdatnietalledeelnemersautomatischeenvoorkeurtoondenvoorhetgebruikvandeApp.Hetgeprinteboekjebleekvoorsommigeatleten voorkeur te hebben. Traditionele implementatiemethoden hebben dusbestaansrechtnaastdenieuwe,innovatievemobielemogelijkheden.Doorhetbestaanvankeuze-optieswordenookdeindividuelevoorkeurenmogelijkhedenvandebetrokkenenerkend.Onsadviesvoorpersonenmetenkelletselenbetrokkenpartnersisdaterruimtemoetzijnvoorpersoonlijkevoorkeuren.DitkanzijnhetgebruikvandeApp,gebruikvanhetboekjeofeencombinatievanbeide.Opdiemanierkandeatleetzelfkiezenwelkemethodevanimplementatie,opwelkmomentdevoorkeurgeniet.Onzebelangrijksteboodschapisdathetprogrammaeffectiefis,maarweluitgevoerdmoetworden.

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DANKWOORDMijnpromotiecombinerenmetmijneigenbedrijfenmijnsportambitieswassoms,netzoalsvoor de deelnemers aan dit onderzoek, balanceren. Prioriteiten stellen, traditionelekantooruren afschaffen en werkplekken inrichten op elke – exotische – locatie warenslechtsdeeenvoudigstemaatregelendienodigwarenomalledrietekunnenblijvendoen.Maarbelangrijkerwasdesteun,deflexibiliteitendeaanmoedigingendieikhiervoorkreegvanzowelEvertalsvanWillem.Alleendoorhunvertrouwen,begripenondersteuning–ookbuitenkantooruren–ishetmegeluktomdezepromotietoteengoedeindetebrengen.Nuallehordeszijngenomenishetgeweldigomditproefschrifttemogenbesluitenmeteenaantalmensendiedaarbijonmisbaarzijngeweest.Hetmooistewatelkvandemensendieikhierwilbenoemenmeheeftmeekunnengeveniseenstukjepersoonlijkeontwikkelingdatikmeeneemvoorderestvanmijnleven.Evert,tijdensmijnsollicitatiegesprekkwamenwevrijsneltesprekenoverhardlopen.Eenpassiedieweallebeidelenenwaarinweelkaarbegrepen.Datbegriphebiktijdenshethelepromotietraject steeds gevoeld. Nooit leek het je te veelmoeite omme te helpen, ookwanneer ik weer eens in het buitenland verbleef. Je hebt me geleerd om steeds mijnschouderserondertezettenenpositiefteblijven.Sterkinhoudelijkzijnéneengoede‘baas’ismaarweinigmensengegeven.Jijbenteenvandieweinigen.Willem,ondanksjedrukkewerkschemavoeldeikmebij jounooitonderzoekernummerzoveel. Je had oog voor mijn beperkingen, mijn andere activiteiten en toonde oprechtbelangstellingvoorallesbuitenhetwerkom.Debloemendie jemestuurdenahetWKdedenmemeerdanjewaarschijnlijkhebtgeweten.Promoverenonderjouwgezagiseeneerdieikvoltrotsdraag.Vanjouhebikgeleerdomaltijdoogtehoudenvoorwatiemandandersbezighoudt.Arno,Nelly,Jeffry,Ton,Abida,Cecillia,Victor,Casper,Lieke,Guus,MarcelenHan,zonderjulliehulpwashetnooitgeluktalledeelnemersterekruteren.Julliehebbenmegeleerdhoehetisomeenschakeltezijntussenbedrijfsleven,wetenschapenpubliekefunctieswaarbijiedersbelanggehoordwordt.Ikvondhetbijzonderomtemerkenhoebereidjulliewarenom dit onderzoek te verbeteren en ruimte te geven in het landschap van sport enblessurepreventie.Ingrid,bedanktvoorjouwtomelozeinzetommeetedenken,meetekijkenenallekleinefoutenoptesporeninmijnartikelen.Ikkenniemanddiezonauwgezetennauwkeurigtewerkgaat.Jehebtmegeleerdomdetijdtenemenomalledetailstecontroleren.Alsjijmijnartikelhadgelezenwasikpasvolvertrouwendathetgeenfoutenmeerbevatte.Ikhoopdatweelkaarnogvaakgaantegenkomen.Ineenprofessionelesettingofinhetzwembad.Marianne,bedanktvoorjebijdrageaandekwalitatieveanalyse.Hetwasmooiomtezienhoejehetonderzoekindookenvolenthousiasmeaandeslagging.Inge,somshebikhetideedatjij24/7werkt.Bedanktvoorallehonderdeneendingendiejevoormehebtgedaanalsikweereensergenstegenaanliep.Enalleanderehonderddieiknieteensdoorhebgehad.

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Beste ledenvande leescommisie;Prof.Dr.A.J. vanderBeek,Dr.G.J.deBruijn,Prof.Dr.G.M.M.J.Kerkhoffs,Prof.Dr.R.J.W.G.Ostelo,Prof.R.Meeusen,Dr.Ir.G.J.M.Tuijthof,bedanktvoordetijdenaandachtdiejulliehebbengewijdaanhetlezenvanmijnproefschriftenhetplaatsnemenindeoppositie.Lievepapa,mamaenMaaike,julliehebbenevengeduldmoetenhebben.Gelukkighebbenjulliedatmeerdanik.Datikuiteindelijkzoupromoverenwasnatuurlijkeengegeven.Alheb ikmaar een klein beetje van het doorzettingsvermogen van papa en de oneindigeleergierigheid van mama geërfd, dan was het een gegeven dat ik uiteindelijk zoupromoveren.Maaike,watjijklaarspeeltalsmama,enzus,daarvaltelkepromotiebijinhetniet.LieveJohn,Fernand,Ann,omaentanteMaaike,julliehebbenevengeduldmoetenhebben.Maarjulliewerdenhetnooitmoeteblijvenvragenhoehetgingmetmijnpromotie.Ikbentrotsdatikjulliefamiliemagnoemen.LieveChris,vanjouleeriknogelkedag.Ikkenniemanddiezoveelcompassieheeftenzoonbaatzuchtig is. Door jou was er alle ruimte om drie functies te combineren entegelijkertijdderusttehebbenommetjoutegenietenvanalleswatwedeafgelopenvijfjaarsamenhebbengedaanEnliefste,vanafnuishetdr.Duifje.

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OVERDEAUTEURMiriam van Reijen (1983) studeerde Ontwikkelingseconomie in Wageningen enBewegingswetenschappenaandeVrijeUniversiteitinAmsterdam.Nahaarstudieverlegdeze haar focus naar de atletiek (marathon, PB 2h41), duatlon en triatlon met als besteprestatieseengoudenmedaillebijhetNKduatlon(2017)eneenzilverenplakophetWKduatlon (2017). Naast haar sport heeft van Reijen haar eigen bedrijf, waarmee zepresentatiesverzorgtovervoeding,hardlopenentraining.In2013,terwijlMiriamtraindeinKenia,schreefzehetHardloperskookboek,gevolgddoordeel2in2016.Echter,hetdoenvan onderzoek bleef aan haar trekken en in 2013 keerde ze terug naar de VU om tepromoveren.Miriamwoont,traintenwerktinAmsterdammethaarvriendChris.