Return  to  sport  progression:    beyond  eccentric  exercise    

Dr  Peter  Malliaras  

Outline  

•  Stretch  shorten  cycle    •  Ra;onale  and  indica;ons  in  tendinopathy  rehabilita;on  

•  Evidence    •  Prac;cal  considera;ons  and  return  to  sport  

Stretch-­‐shortening  cycle  (SSC)  =  walk,  run,  jump  

 

SSC  components  Tendon  s;ffness  

 Force  producing  capacity  

Structural  eg  fibre  type,  architecture  Neuromuscular  eg  RFD  

   

Joint  and  leg  s;ffness  Sprint  /  jump  performance  

 

Farley 1993, Komi 2000, Roberts 2002, Brughelli 2008, Hobara 2008, 2010, Harrison 2004

•  Greater  performance  –  Tendon  recoils  faster  than  concentric  muscle  –  Increase  EMG  –  muscle  poten;a;on,  reflex  

•  Greater  efficiency  –  Length-­‐tension,  force-­‐velocity  –  Passive  energy  -­‐  tendon  

Finni  2000,  Komi  2000,  Finni  2006,  Hof  1983,  2002,  Fenn  1924,  1924b  

Stretch-­‐shortening  cycle  (SSC)  

SSC  and  tendinopathy  

•  Tendinopathy  associated  with  SSC  – Sport,  posi;on,  volume,  frequency  

 •  High  forces,  strain  •  Loading  rate,  energy  absorp;on  

–  Influence  on  tenocytes?    

Zwerver  2011,  Lian  2005,  Malliaras  2008,  Ferred  1986  

Achilles  tendinopathy  deficits  

•  Neuromuscular  deficits  –  Reduced  tendon  s;ffness  

–  Reduced  rate  of  force  development  

 

–  Reduced  hopping  distance  

 

Wang  2012,  Arya  2010,  Child  2010  

Silbernagel  2007  

•  Con;nued  sport  v  no  sport  first  6  weeks  

•  Con-­‐ecc,  eccentric,  faster-­‐power  

•  Greater  drop  CMJ  &  hop  quo;ent  6  months  

902 Silbernagel et al The American Journal of Sports Medicine

There were significant (P < .05) correlations between theinitial VISA-A-S score and the improvements in VISA-A-Sscore seen at the subsequent evaluations: 0 to 6 weeks,r = –.292; 0 to 3 months, r = –.470; 0 to 6 months, r = –.459;and 0 to 12 months, r = –.756.

The same significant (P < .05) correlations were seenwhen comparing the initial pain level with hopping and theimprovements seen in pain level at the subsequent evalua-tions: 0 to 6 weeks, r = –.498; 0 to 3 months, r = –.591; 0 to6 months, r = –.681; and 0 to 12 months, r = –.823.

There were no significant correlations between the dura-tion of symptoms and the change in VISA-A-S score orchange in pain level with hopping at any of the evaluations.

DISCUSSION

This randomized study could not demonstrate any nega-tive effects from allowing the patients to continue Achillestendon-loading activity (such as running and jumping)when using the pain-monitoring model during rehabilita-tion for Achilles tendinopathy.

Furthermore, this randomized treatment study confirmsearlier results that strengthening exercises of the Achillestendon, gastrocnemius, and soleus muscle complex causesignificant improvements in symptoms and muscle-tendonfunction in patients with Achilles tendinopathy.5,21,26,36,41

Historically, in the literature, initial rest from pain-provoking activity has been recommended for Achillestendinopathy,7,30,42 but it appears that this might not benecessary. The patients in this study could safely continuewith their activity of choice as long as they followed thepain-monitoring model. The pain-monitoring model statesthat exercise activity that does not cause pain above 5 of

10 on a VAS is safe. Because most of the patients withAchilles tendinopathy are middle-aged, physically activeindividuals, the allowance of continued exercise activitymay have positive effects on their general health and qual-ity of life. Also, athletes with Achilles tendinopathy wouldpotentially benefit from being able to continue their sportsactivity in order to avoid significant deterioration in sport-ing performance. As in the present study, Visnes et al45 alsoallowed continued physical activity during treatment intheir study on athletes with patellar tendinopathy. Theycould not, however, show any positive effect of eccentrictraining when elite volleyball players with patellartendinopathy continued their normal in-season training.No physical activity-monitoring model, such as the pain-monitoring model used in the present study, was used byVisnes et al45; this might explain the lack of improvement.

It cannot be excluded in the present study that the lackof treatment differences found between the 2 treatmentgroups for the functional secondary outcome evaluationsrepresents a type II error. The power calculation made wasfor the primary and not for the secondary outcomes. Thus,no definite conclusions can be drawn from the results forthe functional evaluations.

The literature states that Achilles tendinopathy mostlyoccurs in middle-aged men. In our study, as well in others, itcan be seen that there is a change over the years in the per-centage of women included. In the often-cited study byKvist,14 it was reported that 89% of the patients withAchilles tendinopathy were men. In a review of several morerecent treatment studies, the percentage of women wasbetween 14% and 55%, with the higher percentages seen inthe later studies.4-7,21,24,27,29-31,38 Because previous studies onAchilles tendinopathy include both men and women, we alsoincluded both men and women in the present study. At thetime we planned the study, we did not expect to have as highas 50% women and did not expect that there would be aneed for controlling the ratio between men and women ineach group to get an equal number. Even though there are 7women in the exercise training group and 11 women in theactive rest group, there is no significant difference in thenumber of women in the 2 treatment groups. However, werecognize that the numbers are low and the chance to detecta difference with statistics is small. Further, statisticalanalysis comparing the 4 groups (women and exercise train-ing, women and active rest, men and exercise training, menand active rest) on the main outcome (change in VISA-A-Sscore) using the Kruskal-Wallis test did not show any sta-tistical differences between the groups. We acknowledgethat gender could be a confounding factor; however, we haveno indication that this factor has affected the outcome of thepresent study. Therefore, we do not believe that the validityof our results is affected by the ratio of men and women inthe different treatment groups.

Even though our results appear similar to earlier stud-ies on the effect of exercise on Achilles tendinopathy,direct comparisons between treatment studies are diffi-cult to make because of variations in outcome meas-ures.5,21,26,36,41 The VISA-A-S questionnaire, used in thepresent study, measures important aspects of the

Figure 1. Mean VISA-A-S scores with 95% confidence inter-val, at 0 and 6 weeks and at 3-, 6-, and 12-month evaluations.VISA-A-S, Swedish version of the Victorian Institute of SportsAssessment–Achilles questionnaire.

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at Kings College London - ISS on January 14, 2010ajs.sagepub.comDownloaded from

Patellar  tendinopathy  deficits  

•  Greater  jump  height  – Precede  and  aier  pain  onset  if  ac;ve    

•  Less  peak  quadriceps  torque  (uni  vs  controls,  bi)    •  Less  peak  jumping  power,  work  

Cook  2004,  Lian  2003,  Visnes  2013  

Crossley  2007  

Bisseling  2007  

Clinical  presenta;on  varies  

Landing  strategy  

•  Ver;cal  vs  horizontal  –  Higher  PT  force  

•  Previous  PT,  asymptoma;c  –  eg  less  PF,  knee  flexion  spike  jump  landing  

–  eg  less  hip  flexion  stop  jump  

Edwards  2010,  2010b,  2013,  Bisseling  2008    

loading the patellar tendon compared with duringvertical landings.Ankle dorsiflexion was significantly less during the

horizontal landing phase compared with verticallanding phase. Malliaras et al. (2006) cautionedthat reduced ankle dorsiflexion range during landingmay increase the risk of developing patellar tendino-pathy by limiting the range of motion over which theankle joint plantar flexor muscles can act, in turn,causing the knee and hip extensor groups to have tocontribute more to this force dissipation (Kovacset al., 1999). The limited dorsiflexion range of move-ment combined with the lower ankle dorsiflexionvelocity displayed by the participants during thehorizontal landing phase may have contributed tothe higher patellar tendon load compared with thatsustained during the vertical landing phase.

In comparison to this study, similar (Yu et al.,2004, 2006; Chappell et al., 2005; Sell et al., 2006;Herman et al., 2008) and varied (Yu et al., 2006)values have been reported previously for knee andhip joint angles during the horizontal landing phaseof the stop-jump movement. Several studies havesuggested that increased knee flexion during landingwas a strong predictor of patellar tendinopathy,whereby athletes with patellar tendinopathy landedwith more knee flexion at initial contact (Richardset al., 1996) and at the time of the FV (Bisseling et al.,2007; Bisseling et al., 2008). It was hypothesized thatlanding with more knee flexion might not onlycontribute to the higher patellar tendon forceobserved in the horizontal landing phase, but as thepatellar tendon is oriented anteriorly at knee flexionangles 4601 (DeFrate et al., 2007), it may also leadto greater compression of the posterior aspect of thepatellar tendon against the patella (Toumi et al.,2006). Greater compression of the patellar tendonhas been suggested to be a cause of proximal patellartendinopathy (Almekinders et al., 2002; Hamilton &Purdam, 2004). We speculate that landing withgreater hip flexion during the horizontal landingphase may potentially add to this compression asthe total body center of mass would be located moreposterior to the base of support, creating a greaterhorizontal shear force at the knee joint (Fig. 6). As aresult of these compressive forces, patellar tendonadaptation may occur in the form of increasing theamount of fibrocartilage, which is known to resistcompressive and shear forces (Benjamin & Ralphs,1998). It is thought this tendon adaptation may be atthe expense of tissue that resists tensile loading,which may, in turn, decrease load tolerance andultimately overload of the patellar tendon (Hamilton& Purdam, 2004).Despite the significantly lower FV in the horizontal

landing phase, the FPT was significantly greaterrelative to during the vertical landing phase. TheFPT is derived by dividing the knee joint moment bythe patellar tendon moment arm. Knee joint mo-ments are calculated via a complex equation incor-porating both the kinetics and kinematicscharacterizing the lower limb during the landingaction (Winter, 1990). In the present study, varia-tions in the patellar tendon moment arm could notexplain between-phase di!erences in the FPT as theparticipants displayed similar amounts of knee jointflexion at FPT during the two landing phases (Herzog& Read, 1993). Therefore, the significantly higherknee joint moment was attributed to the significantlyhigher FPT found in the horizontal landing phase(Fig. 2). We speculate that the higher knee jointmoment was primarily due to the direction of thevector of the resultant ground reaction force, whichcreated a larger knee joint moment arm by increasing

Fig. 6. Lower limb alignment during the horizontal andvertical landing phases of a stop-jump movement at initialfoot-ground contact (IC) and at the time of the peak patellartendon force (FPT). Note the more posterior direction of thevertical ground reaction force vector and the altered tibialalignment during the horizontal landing phase comparedwith the vertical landing phase.

Patellar tendon loading during landing

7

Systematic review of AT & PT Loading programs

Limited evidence that eccentrics are superior to other loading

 

Malliaras et al 2013

  Alfredson   Stanish &Curwin  

Silbernagel   HSR  

Type of exercise  

Eccentric   Eccentric-concentric Faster eccentric-concentric  

Eccentric-concentric Eccentric Faster eccentric-concentric Balance exercise Plyometric  

Eccentric-concentric  

Sets, reps   3x15   3x10-20   Various   4 x 15 to 6  

Frequency   Twice daily   Daily   Daily   3x/week  

Progression   Load   Speed then load   Volume Type of exercise  

Load  

Pain   Enough load to achieve up to moderate pain  

Enough load to be painful in third set  

Acceptable if within defined limits  

Acceptable if was not worse after  

Sports  Medicine  Systema;c  Review,  Malliaras  et  al  2013  

Clinical  SCC  loading  

•  Romero-­‐Rodriguez  2011  –  n=10,  50%  ac;ve  in  sport  –  Patellar  tendinopathy  –  Improved  VISA  86%  –  No  increase  jump  height  

 

•  Flywheel  training,  eccentric  cycling  –  Increased  leg  spring  s;ffness  

Elmer  2011    

SSC  training  •  Jumping  

–  Ver;cal  –  Forward  –  Hurdle  –  Drop  jumps  20-­‐70cm  step  

•  Power  training  –  Squat  jumps  

•  Bounding  

What  can  SSC  rehabilita;on  offer?  

•  Increased  rate  force  development  (RFD)  –  Burgess  2007,  Kyrolainen  2005,  Kubo  2007,  Wu  2009  

•  Improved  jump  performance  –  Burgess  2007,  Kyrolainen  2005,  kubo  2007,  Houghton  2013,  Foure  

2009,  Taube  2012,  Wu  2009  

Tendon  s;ffness  •  Inconsistent  outcomes  

–  Increases  (e.g.  Wu  2009,  Burgess  2007)  

–  No  change    (e.g.  Kubo  2007,  Houghton  2013)  

•  No  change  aier  walking,  running  programs                          (e.g.  Hansen  2003,  Kubo  2008)  

 

   

Tendon  s;ffness  

•  Burgess  2007  – Warm  up  then  60-­‐80  maximal  drop  jumps    – 2  sessions/week,  6  weeks  =  840  jumps  

•  Kubo  2007  – Warm  up  then  50  drops  jumps,  20cm  – 4  sessions/week,  12  weeks  =  2400  jumps  

Resistance  versus  SSC  

•  12  weeks  of  resistance  training  vs  plyometric  training  

–  Tendon  s;ffness  increased  with  weight  training  

–  Jump  performance  increased  with  plyometrics  

 

Kubo  2007,  Markovic  2007  

Copyright @ 200 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.7

Electromyographic activity. The electromyographicactivity (EMG) was recorded during the measurements ofthe maximal voluntary isometric strength, tendonproperties, and jump performances. Bipolar surfaceelectrodes (5 mm in diameter) were placed over the belliesof MG, LG, SOL, and tibialis anterior (TA) muscles with aconstant interelectrode distance of 25 mm. The electrodeswere connected to a preamplifier and differential amplifierwith a bandwidth of 5 Hz to 500 Hz (model 1253A, NECMedical Systems, Tokyo, Japan). The EMG signals weretransmitted to a computer at a sampling rate of 1 kHz. TheEMG was full-wave rectified and averaged for the durationof the contraction (mEMG). During the jumping tests, themEMG values from MG, LG, SOL, and TAwere calculatedfrom the prelanding (defined as 100 ms preceding landing),eccentric and concentric phases, respectively, according tothe ankle joint angle. In addition, the mean of mEMG in theMG, LG, and SOL was defined as the mEMG of plantarflexors. During the measurements of tendon properties, themEMG of TA was measured to investigate the antagonistmuscle activity of TA (coactivation level). To determine themaximal activation of TA, a maximal dorsiflexion isometriccontraction was performed at the same angle (90- of anklejoint). We normalized the mEMG value of TA with respectto the mEMG value of TA at the same angle when acting asan agonist at maximal effort.

Statistics. Descriptive data included means T SD. Atwo-way ANOVA with repeated-measures [2 (groups) ! 2(test times)] was used to analyze the data. The F ratios formain effects and interactions were considered significant atP G 0.05. Significant differences among means at P G 0.05were detected using a Tukey post hoc test.

RESULTS

The muscle volumes of the plantar flexor musclesincreased significantly 4.9 T 2.3% for PT (P = 0.003) and5.4 T 2.8% for WT (P = 0.002), respectively (Table 1). Nosignificant difference in the relative increase of musclevolume was found between PT and WT (P = 0.379). Therewere no significant differences in the relative increase in themuscle volume among MG, LG, and SOL (Fig. 1).Furthermore, no significant change in the Achilles tendonCSA was found between both the protocols (Table 1).

The MVC value increased significantly by 17.3 T 21.7%for PT (P = 0.017) and 19.3 T 13.6% for WT (P = 0.003),respectively (Table 1). There was no significant differencein the relative increase of the MVC value between the twoprotocols (P = 0.818). The activation level of the plantarflexor muscles assessed by superimposing electrical stimuliincreased significantly by 5.6 T 6.6% for PT (P = 0.019)and 5.8 T 8.2% for WT (P = 0.049), respectively (Table 1).No significant change in the coactivation level was foundafter training for PT (P = 0.771) and WT (P = 0.549),respectively (Table 1). Although the twitch torque valueand the rate of torque development did not change for both

the protocols, the time to peak torque shortened signifi-cantly for PT (P = 0.011) but not for WT (P = 0.499)(Table 1).

Both protocols produced no significant differences in thetendon-elongation values at any force-production levelsafter training (Fig. 2). The maximal tendon elongation andelastic energy increased significantly for PT (tendonelongation P = 0.031, elastic energy P = 0.044), but notfor WT (tendon elongation P = 0.374, elastic energy P =0.681) (Table 1). The relative increases in the maximaltendon elongation and elastic energy were greater for PTthan for WT (tendon elongation P = 0.032, elastic energy

FIGURE 3—The relative changes in the jump height of SJ, CMJ, andDJ for plyometric and weight training protocols. The relative increasesin the SJ, CMJ, and DJ heights were significantly greater for PT thanfor WT. ** P G 0.01; *** P G 0.001.

http://www.acsm-msse.org1806 Official Journal of the American College of Sports Medicine

APP

LIED

SCIENCES

Pathology  changes  

•  Less  fluid  flow  response  with  loading  –  Aggrecan  

•  Reduced  s;ffness  aier  resistance  training  

•  Neuromuscular  adapta;on  more  realis;c  

Grigg  2012  ,  Docking  2013  

Kongsgaard  2010  

Indica;ons  for  specific  SSC?  

•  Con;nued  sport  possible  for  some  •  Quick  return  to  sport  within  season  

–  Inseason  management  of  symptoms  – Return  to  sport  criteria?  Pain,  training  capacity  

•  Spectrum  of  presenta;ons  clinically  – Pain  /  confidence  – Kinema;cs  eg  poor  eccentric  control,  s;ff  knee  – Performance  eg  hop  distance  

Hop  kinema;cs   Hop  distance  

Low  intensity  •  Pain  •  Motor  paperns  •  Endurance    •  Jumps  •  Hops  –  Achilles  ++  •  Box  

Landing  strategy  

•  Replicate  landing  

e.g.  block  jump  landing  •  Land  on  toes  •  Soi  landing  

•  Hip  flexion  difficult  in  volleyball  

 

Eric MacLean A Theoretical Review of Lower Body…

3

for executing effective lower body plyometric training. The conclusions stated in this work, and the biomechanical points identified, can be applied to understanding the biomechanics of lower body plyometrics, as the primary movement pattern of lower body plyometric training is the multi-jointed squat position; an action that utilizes the triple flexion / extension of the ankles, knees and hips to generate force production and high power outputs (2,7). Figure 1 represents the ‘athletic position’. This position is achieved when there is lower extremity bilateral symmetry, and equal body weight distribution across all joints and limb segments. Mastery of this position is granted only when it can be maintained in static and lateral movement patterns. It is this position which acts as the basic start and landing position for all two legged jumps.

Figure 1 – The Athletic Position in Triple Flexion

The athlete in Figure 1 is attempting to

highlight the key biomechanical points outlined in the literature associated with force production and power output. These key points include the feet being shoulder or slightly greater than shoulder width apart, the knees remaining posterior to the distal aspect of the feet, where the feet are oriented in the sagittal plane, in line with the patella, where the centre of the patella does not drift past the lateral aspect of the foot. Feet must remain forward with an angular displacement from the midline of the shank no greater than 10o-15o, with hip flexion at approx 90o (1).

The stated biomechanical limb positions are suggested based on the following collection of reported findings related to force production, power output, and decreased risk of injury.

While active in bounding, hopping, or jumping movements, either single or double legged, deep knee flexion during the eccentric phase of the movement, and complete triple extension of the

ankles, knees and hip should be encouraged during the concentric phase of the movement, as illustrated in Figure 2. These joint position recommendations are given as the factors established as being major determinants of vertical jump performance; force developed from the hip, knee and ankle joints, and the rate of force development produced by these muscles (3), and the neural control of the movement (2).

However, before the particulars of the concentric, explosive phase of the movement is discussed, the eccentric, force and power producing flexion aspect of the jump must be analyzed.

Figure 2 – Concentric phase of a Medicine Ball jump squat.

Escamilla et al reported that, greater forward knee movements during the descent (eccentric) phase of the squat are shown to increase knee shear forces (1). This is important biomechanical error to consider in relation to performing plyometric exercises, as the speed at which the movements take place are purposefully quick, and as such creates an element of instability. Further, several studies have reported significant greater tibiofemoral shear and compressive forces during a fast squat cadence (1). Escamilla et al report that the fast decent rate of a squat movement requires greater deceleration forces from the knee and hip extensors in order to slow down and stop the body system (body plus added resistance) at the bottom of the decent (1). If the athlete is in poor biomechanical alignment, the unequal distribution of these forces has the potential to increase the magnitude of the compressive forces to the stabilizing structures of the knee joint; namely the bursa, medial and lateral meniscuses, or collateral and cruciate ligaments. It is the unequal distribution of these compressive forces which have the strength to create myotendinous or joint capsule injury.

Chmielewsky  2006,  Flanagan  2008  

Landing  challenges  

•  Stop  jump  – eg  basketball  

•  Proximal  kine;c  chain  

 

Performance  

•  Minimise  hysteresis  –  <25ms  contact  ;me  

•  Progress  intensity  but  not  at  expense  of  speed  

•  Single  leg    •  Ver;cal  •  Forward  •  Hurdle  

Chmielewsky  2006,  Flanagan  2008  

When  to  start?  

•  Stable  pain,  but  present  •  Reasonable  kinema;cs  •  Side  to  side  isolated  &  compound  strength  

– Leg  extension  – Leg  press  – Calf  raise  

How  to  progress?  

•  Start  asap  

•  Every  2-­‐3  days  -­‐  tenocytes?  pain?    •  Pain  /  endurance  –  5-­‐10  mins  •  Motor  paperns  –  5x10  •  Performance  –  5x10,  5x5  

– Stable  pain  before  progressing  

Isometric  Kine;c  chain  

Isometrics  for  load  Concentric-­‐eccentric  –  isolated  Concentric-­‐eccentric  –  compound  Eccentric?  

Hopping   Landing  Running  

Performance  -­‐hops  -­‐cudng  -­‐sprint  

Sport  à  

Return  to  sport  =  stable  pain,  strength,  motor  paperns,  performance  à  

Summary  

•  Limited  evidence  for  SSC  rehab  –  Look  for  individual  indica;ons  

•  No  evidence  on  return  to  sport  criteria  –  Pain,  strength,  movement  paperns,  performance  

 •  Achilles  –  low  intensity,  endurance  •  Patellar  –  motor  paperns  

Twi$er:  @DrPeteMalliaras  

Case  1  •  A  young  talented  player  

with  symptoms  in  the  patella  tendon  (on  and  off  pain  during  warm  up  or  aier  training,  beper  during  ac;vity)  during  the  preseason  training    

•  what  to  do?  •  con;nue  training?  adjust  

training?  add  treatment?    

Modify  training  based  on  pain  response  What  are  the  deficits?  Address  these  in  parallel  

Case  2  •  A very important player

during season experience increasing symptoms (pain and stiffness in the morning) in the Patellar Tendon weeks before an important match

•  What to do ?? Modify load Isometrics High volume injection Other eg heel wedges, tape

Case  3  •  One  of  your  players  

experiences  sudden  onset  of  pain  in  the  inser;onal  Achilles  tendon  during  training  but  only  during  high  loading.  

•  What  to  do  ?    Imaging  Clinical  signs  of  tear?  Fascia  crura