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ournal of Science and Medicine in Sport (2007) 10, 403—410

RIGINAL PAPER

arm-up or stretch as preparationor sprint performance?

atthew Stewarta, Roger Adamsb, Albert Alonsoc,∗,lake Van Koesveldb, Scott Campbell c

SportsPhysio West, 116 Macquarie Street, Parramatta, NSW 2150, AustraliaSchool of Physiotherapy, Faculty of Health Sciences, University of Sydney,idcombe, NSW 1825, AustraliaBulldogs Rugby League Football Club, Belmore, NSW 2192, Australia

eceived 31 January 2006; received in revised form 20 September 2006; accepted 4 October 2006

KEYWORDSWarm-up;Stretch;Sprint;Randomised controlledtrial

Summary Warm-up and stretching are widely used as techniques in preparationfor intense physical activity, yet there is little information available to compare theireffectiveness in relation to athletic performance. Fourteen elite Under-19 year oldrugby league footballers undertook each of four preparation protocols (no prepa-ration, stretching only, warm-up only, warm-up and stretching) in four successivetesting sessions. Protocols were randomly allocated to players in a counterbalanceddesign so that each type of preparation occurred equally on each day of testing.During each session, athletes performed three solo sprint trials at maximum speed.Sprints were of 40-m distance and were electronically timed with wind speed anddirection recorded. Preparation involving warm-up resulted in significantly fastersprint times compared to preparations having no warm-up, with a diminishing effect

over the three trials. On the first trial, warm-up resulted in a mean advantage of0.97 m over 40 m. Stretching resulted in a mean disadvantage of 0.18 m on the firsttrial, and no significant effect overall despite significant wind assistance. Warm-upwas effective at improving immediate sprint performance, whereas an equivalent

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duration of lower limb© 2006 Sports Medicine

ntroduction

re-exercise stretching is a convention among ath-etes worldwide.

∗ Corresponding author at: 4 Ethel Street, Burwood, NSW 2134,ustralia. Mobile: 61 411 798 897; fax: +61 2 9718 8012.

E-mail address: albert alonso@connexus.net.au (A. Alonso).

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440-2440/$ — see front matter © 2006 Sports Medicine Australia. Publisheoi:10.1016/j.jsams.2006.10.001

tching had no effect.tralia. Published by Elsevier Ltd. All rights reserved.

The three key perceived benefits of stretch-ng prior to athletic activity are: reduced riskf injury, decreased post-exercise muscle sore-ess and improvement in athletic performance.1

ecent large randomised controlled trials have

uestioned the validity of this perceived reduc-ion in injury risk2,3 and there is no proveneduction in post-exercise muscle soreness afterre-exercise stretch.1 Yet pre-exercise stretching

d by Elsevier Ltd. All rights reserved.

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remains widespread, possibly due to the percep-tion that it may improve athletic performance. Cur-rently, there are few studies that have directlyinvestigated the effect of stretching prior to theperformance of a sprint. One recent study has indi-cated that pre-exercise stretching may negativelyimpact on a 20-m sprint.4

Similarly, the process of warm-up is acceptedand performed prior to nearly every athleticevent.5,6 Clinical research regarding warm-up andits effect on subsequent athletic activity is limitedand often confounded by it being combined withother interventions.6 To date, no research study hasexamined the relationship between warm-up andinjury risk, and those that have looked at warm-upand post-exercise muscle soreness did not find anypreventive effect.7—9 The effect of warm-up on ath-letic performance has been widely studied,10—15,but the research does not consistently demonstratea link between warm-up and enhanced perfor-mance. This is likely to be attributable to widevariations in the warm-up mode, duration, inten-sity and length of recovery (time delay betweencessation of warm-up and commencement of per-formance) employed in the various studies.

The aim of the present investigation is to com-pare the effect of no preparation, pre-exercisestretching, pre-exercise warm-up and a combina-tion of warm-up and stretching on 40-m sprintperformance in elite under-19 rugby league foot-ballers. By specifically looking at warm-up andstretching, individually and in combination, thepurpose is to determine if these commonly usedpre-athletic activities do enhance performance.Accordingly the hypotheses are that preparationsinvolving warm-up will result in faster sprint per-formance than those without warm-up and thatpreparations involving stretching will result in bet-ter performance than those without stretching.

Methods

Study design

A randomised, four condition, repeated measuresdesign using a counterbalanced format, allowingsubjects to act as their own controls.

tact

Table 1 Latin square arrangement of group conditions for

Day 1 Day 2

Group A No preparation Warm-up onlyGroup B Warm-up only Warm-up and stretchinGroup C Warm-up and stretching Stretching onlyGroup D Stretching only No preparation

M. Stewart et al.

ubjects

ubjects were elite athletes, playing for the Bull-ogs Rugby League Club, participating in the Newouth Wales (Australia) Rugby League Under-19state Competition. All subjects were required to beree of injury on all 4 days of data collection. Priornformed consent was obtained from each subjectnd approval was granted by the Human Researchthics Committee of The University of Sydney. Of7 subjects who initially consented to participaten the study, three were unable to attend all 4 test-ng days. The remaining 14 subjects who completedll four testing sessions were included in the datanalysis.

rocedures

ubjects were randomly allocated into four groups,hen each group was randomly allocated to a test-ng condition. The groups cycled through the fouronditions in order over 4 testing days, Tuesday andhursday of 2 successive weeks (Table 1). Randomllocation was achieved using a random numberable (Rand Corporation 1955) and a blind alloca-or. After the allocation process, the groups wereamed (A, B, C, D) to resemble the order of testing.ach member within a group was given a number sohat they could be identified by codes (e.g. A4, B2)hich were marked on the leg of individual athletesvery testing day.

All subjects were instructed to perform onlyheir ‘normal’ activity (such as work or study)nd were requested not to undertake any exerciser stretching activities prior to testing. Scheduledeam training occurred after testing. To optimisehe trade-off between experimental control andxternal validity, the testing was conducted out-oors with exposure to wind changes, but on aoncrete surface to give all runners good footing.ubjects were asked to wear appropriate runninghoes for the concrete test surface and to wearhe same shoes on each testing day. Throughout

he structured warm-up and stretching sessions, thethletes were supervised by the club’s strength andonditioning coach and given standardised instruc-ions. The instruction to perform the 40-m sprint to

testing

Day 3 Day 4

Warm-up and stretching Stretching onlyg Stretching only No preparation

No preparation Warm-up onlyWarm-up only Warm-up and stretching

Warm-up or stretch as preparation for sprint performance? 405

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tribute the most to the running action.17

Each athlete was asked to sprint the length ofa marked 40-m track from a standing start. Test-ing involved three 40-m sprints, at 3-min intervals,

Figure 1 Representation of the warm-up circuit.

he best of their ability was always given prior toommencement.

Each preparation condition was run on a strict2-min cycle. At the completion of the allocatedreparation, subjects proceeded directly to theprint testing area and commenced the first sprintithin 1 min. Subjects allocated to the no prepa-

ation condition on any given day arrived and wentirectly to the sprint testing area.

The warm-up protocol had two major compo-ents. Phase 1 involved travelling 1000 m around aircuit at various speeds. Athletes were instructedo perform three laps of a measured circuit (334 m,ig. 1) in the following sequence: 1/2 lap walking,/2 lap jogging, 1/2 lap striding out, 1/2 lap jog-ing, 1/2 lap striding out and 1/2 lap jogging. Theubjects then walked to the field’s goal line (1/4ap).

Phase 2 involved four ‘run-throughs’ each of0 m. The subjects were instructed to run at a pace0% faster than when ‘‘striding out.’’ The 50-m run-hroughs were started at 60-s intervals, allowingime for the subjects to walk back to the startingosition. The 50-m runs commenced at 7.5, 8.5,.5 and 10.5 min. Upon completion, the subjectsalked directly to either the stretching or sprint

esting area.Stretching was performed utilising a structured

2-min protocol supervised by the strength and con-itioning coach. Subjects were instructed to movento the stretch position to ‘‘feel the stretch butithout pain’’. Each single static stretch was held

or 45-s duration, in accordance with the findings ofagnusson et al.16 Stretches were performed bilat-rally (i.e. right then left) to each muscle group,nd then repeated.

The following muscle groups were stretched in

rder:

posterior lower leg musculature (Fig. 2);posterior thigh (Fig. 3);anterior thigh and hip (Fig. 4).

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igure 2 Static stretch of the posterior lower leg mus-ulature.

These muscle groups were selected as they con-

igure 3 Static stretch of the muscle groups of the pos-erior thigh.

406 M. Stewart et al.

Table 2 Preparation conditions mapped out withinthe 2 × 2 arrangement of the factors warm-up(Yes/No) and stretching (Yes/No)

Stretching

Yes No

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Figure 4 Static stretch of the anterior thigh and hipmuscle groups.

on each testing day. Two sets of electronic timinggates (SPEED LIGHT Sports Timing System, by SwiftPerformance Equipment 1998) marked the starting(0 m) and finishing (40 m) points of the sprint. Thegates recorded times automatically to the nearest0.01 s, ensuring an accurate assessment of sprintperformance.

Athletes commenced each trial in their owntime, starting 1 m before the first gate to eliminatethe effect of reaction time to a starter’s instruc-tion and avoid triggering the first electronic gateprematurely. The subjects were instructed to con-tinue sprinting at maximum effort until the finishinggate.

Because wind can either assist or hinder sprintperformance, wind speed and direction wererecorded in accordance with International Associ-ation of Athletics Federations (IAAF) regulations.A wind gauge (Springco Athletics, USA) was posi-tioned 1.22 m above and within 2 m of the track.Wind speed and direction recordings were takenat 3-min intervals, immediately prior to the com-mencement of each ‘round’ of sprints. Wind speed

was measured in metres per second in either a pos-itive (tailwind) or negative (headwind) direction.

In addition, the athletes were asked to completea single page questionnaire immediately following

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Warm-upYes Warm-up and stretching Warm-up onlyNo Stretching only No preparation

heir sprint testing on each day. This instrumentsed 10 cm visual analogue scales (VAS) with thextremities labelled ‘‘my worst performance’’ and‘my best performance’’. The athletes rated theirerceived level of performance for each individualprint trial.

ata analysis

he analysis was performed using SPSS for Win-ows V12.0. In the data set of 168 sprint times,our sprints (each by a different subject) were per-ormed without the finish gate switch being acti-ated and a time recorded. Computation of rownd column means was carried out to enable esti-ates to be made for the missing values for each

print and the missing values to be replaced. A× 2 × 3 fully repeated measures analysis of vari-nce, with factors stretch (Y/N), warm-up (Y/N)nd Trial (1—3), was conducted on the 40-m sprintimes (see Table 2). Trend component analysis toxamine changes in sprint times across the threerials was conducted with the SPSS polynomial con-rast option within the ANOVA. In addition, a sepa-ate 2 × 2 ANOVA was conducted on the data fromhe first trial only and specific comparisons carriedut examining warm-up only and stretch only. Theame ANOVAs were applied to the VAS data. Sta-istical significance throughout was determined bybtaining a p-value of <0.05.

esults

he 40-m sprint mean times for each trial and con-ition are displayed in Fig. 5.

In terms of main effects associated with thetudy factors, sprints preceded by a warm-up wereerformed in a mean time of 5.479 s comparedo the slower 5.538 s without warm-up, and thisifference was significant (F = 6.27, p = 0.026).

hen stretching preceded sprint performance,ean time was 5.52 s compared with the faster

.497 s without stretching preparation, but this dif-erence was not significant (F1,13 = 0.043, p = 0.84).

Warm-up or stretch as preparation for sprint performance? 407

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Figure 5 40-m sprint mean t

Since on each day three sprints were undertakeny each subject, the trend analysis involved twondependent components; linear and quadratic.he first of these trend tests examined for straight-

ine effects across the three trials and the sec-nd examined for any turning points in the val-es. Both the linear (F1,13 = 26.6, p = 0.0002) andhe quadratic (F1,13 = 14.8, p = 0.002) trend compo-ents applied to the trials factor were significant,ndicating that, while sprints became faster acrosshe three trials, the time reduction between Trial 1nd Trial 2 was significantly greater than that whichccurred from Trial 2 to Trial 3. There was only oneignificant interaction; that between the warm-upnd trials factors (F1,13 = 10.7, p = 0.006), wherebyhe amount of advantage of a warm-up prepara-ion over no warm-up diminished across the threeprints (see Fig. 5).

To examine the effect of preparation type onrial 1 sprint performance, a 2 × 2 ANOVA was con-ucted using only the data from the first trial ongiven day. Warm-up preparation was associated

aqTa

for each trial and condition.

ith significantly faster sprint times than in noarm-up (F1,13 = 12.53, p = 0.004) at 5.514 s com-ared to the longer 5.641 s without warm-up. Thisas not so for stretching, where stretching prepara-

ion, at 5.594 s, was not significantly different fromprinting without stretching preparation, at 5.561 sF1,13 = 0.45, p = 0.51).

Finally, the preparation conditions of warm-p only and stretch only were compared withhe no preparation condition. Warm-up only5.449 s) was significantly faster than no prepa-ation (5.545 s) (F1,13 = 8.56, p = 0.011) whereastretch only (5.531 s) was not significantly differento no preparation (F1,13 = 0.08, p = 0.78).

VAS ratings of performance were not affectedy either stretch or warm-up being in the prepa-ation, but the change in mean VAS rating acrosshe three trials, from 52 to 75 then 74, gener-

ted significant linear (F1,13 = 10.14, p = 0.007) anduadratic (F1,13 = 9.22, p = 0.01) trend components.here was also an interaction between warm-upnd the trials factor, with the amount of perceived

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performance improvement across trials being sig-nificantly greater with warm-up in the preparationthan without it (F1,13 = 6.345, p = 0.026). Consider-ing performance ratings on Trial 1 only, the meanof ratings made without time knowledge was higherwith warm-up (56.5) than with no warm-up (48.5)and this difference was significant (F1,13 = 4.837,p = 0.047).

Tests performed with a warm-up had a meanheadwind 0.33 m/s compared to 0.62 m/s for thosewithout a warm-up. This difference was not signif-icant (F(1,44) = 0.374, p = 0.544). However, a signifi-cant difference was found between wind recordingswhen subjects had stretched compared with whenthey had not (F(1,44) = 5.025, p = 0.03). In this case,the stretch condition was favoured by a lower meanheadwind of 0.06 m/s compared with a mean head-wind of 0.93 m/s for the trials without stretching.

Discussion

The first aim of this study centred on the effect ofpre-exercise warm-up on sprinting performance byelite rugby league footballers. The results demon-strate that warming-up conferred a significantsprint speed benefit (p = 0.026), with a mean advan-tage across three trials of 0.06 s over 40 m. Whilethis corresponds to a benefit of 0.45 m of extra dis-tance for a sprint of 5.5-s duration, the mean effectfrom warm-up observed on trial 1 (0.13 s) equatesto a 0.97 m advantage. The result of the pair-wisecomparison of warm-up only versus no preparationshowed a mean improvement in performance of0.10 s, or 0.74 m for those who warmed up. In com-petitive sport, being almost a meter ahead over40 m on the first sprint effort is an advantage.

All groups demonstrated improvement in theirsprint times across trials, which was likely becauseof a warm-up effect conferred by the test sprintsthemselves. The warm-up over no warm-up advan-tage of 0.13 s seen at Trial 1 reduced to a differenceof less than 0.01 s by Trial 3. Thus, the improvementin performance following the 12-min warm-up pro-tocol was effectively matched by performing two40-m sprints at 3-min intervals. This suggests thathigher intensity, shorter duration warm-ups maybe more appropriate for athletes about to under-take sprint activity. Thus, mechanisms for warm-up may not rely entirely on changes to muscle orcore body temperature. Post-activation potentia-

tion (PAP) has been suggested to improve contrac-tile performance, especially in type II, fast-twitchmuscle fibres18 and has been demonstrated fol-lowing pre-conditioning exercise bouts of only 10-s

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M. Stewart et al.

uration.19,20 It is also proposed that physical activ-ty may act to disturb chemical bonds formed dur-ng rest between actin and myosin filaments.21,22 Arief warm-up could reduce the passive stiffness ofuscle,23 contribute to increased power and rate

f force development during short-term athleticasks.

It is also possible that increased psychologicalreparedness arising from pre-existing attitudesbout what constitutes optimal preparation maynfluence performance where there is a brief butask-specific preparation. The results of the ques-ionnaire used here indicate that warming-up washe only factor associated with a difference in howell the athletes believed they had sprinted, withigher ratings given after sprints with a warm-up.he most likely explanation would seem to be thathe higher self-assessments were simply becausehe athletes knew, even without time feedback,hen they had completed a fast performance.This study’s second aim was to determine the

ffect of pre-exercise stretching on sprinting per-ormance. From the repeated measures analysis,tretching did not have any significant effect. Sta-istical analysis also revealed that mean sprint timefter stretching was in fact assisted by the windonditions in our study. The mean headwind experi-nced after the stretching conditions was 0.87 m/sess than the headwind for the no stretching condi-ions (i.e. warm-up only and no preparation). Basedn data obtained from elite 100-m sprinters,24 thisorresponds to an advantage of 0.02 s favouringhe stretching condition and suggests that, if any-hing, stretching could have even been detrimentalo performance, which has been a finding of pre-ious research.4 In the current study, a pair-wiseomparison showed pre-exercise stretching was notignificantly different from doing no preparation atll (p = 0.78). Thus, the results demonstrate thatupervised static stretching did not significantlymprove sprinting performance in elite under-19ugby league players.

It remains possible that stretching may improveertain aspects of sprint performance but simulta-eously hinder others, so that any overall effects minimal. For example, an increase in musculo-endinous extensibility and range of motion fol-owing stretching may improve stride length,25—27

ut increased musculotendinous compliance couldlso reduce the efficiency of the stretch-shorteningycle,28 thereby reducing sprinting economy.

Comparison of the warm-up only and the

ombined warm-up and stretch conditions showsower performance for the combination of warm-p followed by stretching, and this differencepproached statistical significance (p = 0.075) This

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arm-up or stretch as preparation for sprint perfor

ay indicate that stretching reduces the bene-t achieved by warming-up. However, it is morerobable that this was a sequence effect becausen the combined warm-up and stretch condition,he warm-up preparation preceded the stretchingeriod, causing a delay of 12 min from the cessationf warm-up to sprint Trial 1. This delay may haveeen long enough to return muscle temperature29

o near baseline levels and thus to diminish the ben-fits of PAP.30,31

It is important to note that this study specifi-ally relates to warm-up and stretching immedi-tely prior to sprint performance. The results do notreclude the possibility that a long-term stretchingrogram could assist sprint performance by increas-ng range of motion. The potential role of stretch-ng at times other than pre-exercise is not yetully understood. Further research is required toetermine the efficacy of other methods of stretch-ng. While warm-up conferred a decided advan-age in sprints undertaken immediately afterwards,he effect of variations in warm-up intensity anduration in sports other than sprinting remainsnknown.

onclusion

his study demonstrated that warm-up undertakenefore sprinting significantly improved 40-m sprinterformance in elite under-19 rugby league players.tatic stretching prior to sprinting did not have anffect on performance. Furthermore, the benefitseceived from following a 12-min warm-up protocolere effectively matched by performing two 40-m

prints.

Practical implications

• A 12-min warm up improves 40-m sprint times.• A 12-min static stretch has no effect on subse-

quent sprint time.• A 12-min warm up followed by 12-min static

stretch gave no advantage over warm up aloneon subsequent sprint time.

• Two 40-m sprints effectively matched the ben-eficial effect of a 12-min warm up on subse-quent sprint time.

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