Introduction.Current Anterior Cruciate Ligament Reconstruction (ACLR) rehabilitation protocols often focus on three major tenets: 1) protection and facilitation of the graft, 2) improving knee range of motion and strength to “within normal limits” and 3) passing of “established” return to sport testing, most notably single-leg hop testing, quad strength greater than 85% of uninvolved limb, etc. Despite hundreds of articles high-lighting these points, incidence of re-injury continues to be high and further, it has been demonstrated that even if there is no re-injury, only 63% of athletes return to their pre-injury level of performance (Ardern CL, 2011). This suggests that current rehabilitation models and return to sport parameters may not be addressing the appropriate deficits.

At Nevada PT, we are evidence-led and the evidence suggests that the key to successful rehab lies in appreciating the multi-factorial nature of ACL injury and re-injury. Improved hamstring strength (in addition to established quadriceps protocols), equal lower extremity activation during athletic movements such as jumping, cutting, etc., improved core strength, more stringent return to sport benchmarks are but a few of the multi-pronged approach we use. Additionally, the timeline of graft healing may be much longer than previously thought as some grafts show healing continuing past the two-year mark. Finally, the establishment of an acceptable “chronic workload” as an athlete or patient is resuming athletic participation is an update on the “envelope of function” concept (with new objective risk factor ratios) and may become a cornerstone of reducing injury risk throughout not only ACL injuries, but rehabilitation in its entirety.

(6monthversus10monthACLgraftonMRI,RabuckSJ,2013Jan).

While the following protocol borrows many tried-and-true rehabilitation theories from the best in sports medicine, it also incorporates new progressive models to address the above-mentioned goals.

Phase 1 Progressions: The patient needs to be seen frequently and aggressively immediately after surgery to facilitate the completion of phase 1 goals. It is imperative to manage excessive inflammation and swelling as early as possible post-op while progressing extension as tolerated. Symmetrical extension should be achieved as early as possible, with a goal of achieving equal bilateral hyperextension within the first 1-2 weeks. Additionally, normalizing patellar mobility, preventing or minimizing scar tissue formation and facilitating improved quadriceps activation (Wilk KE, 2012 Mar) should be emphasized at this time. If abnormal scar tissue is allowed to form, extension deficits may persist or if the inflammatory cycle is allowed to continue after the first few weeks, the patient may have continued difficulty throughout the ACL rehabilitation program. Aggressive pursuit of phase 1 goals often sets the table for a smooth rehabilitation progression in the next several months.

Improved Hamstring Activation/Decreased Hamstring Laxity: Hamstring laxity has been suggested as a primary indicator for ACL injury susceptibility, specifically in the female population (Hewett TE, February 2006). Additionally, hamstring activation unloads shear forces on the ACL, especially during athletic movements such as cutting and sidestepping (Weinhandl JT, June 2014) and it would follow that a program emphasizing ACL repair protection would have a heavy hamstring component while continuing the well-established quadriceps and hip musculature strengthening of established programs. The following protocol addresses this in multiple approaches: primarily in the form of deadlift progressions (Escamilla RF, 2002 Apr) such as assisted band-work, bodyweight and single-leg movements, kettlebells and finally barbell work as appropriate. While squat progressions are well known (yet amazingly still under-utilized), very few protocols incorporate deadlifts and if they do, it is often in a single-leg platform with a balance emphasis. Additionally, hamstring weakness when matched to their male counterparts, as opposed to quadriceps weakness, may be a bigger predictor for ACL injury and subsequent re-injury in females (G.D. Myer, 2009). Not only is the deadlift when performed correctly safe for ACL repairs, it is a compound multi-joint hamstring dominant movement requiring strong core activation. Hamstring and core weakness are well-documented risk factors for ACL injury and are often underemphasized components of many rehabilitation programs.

Improved Core Strength: It has been theorized that poor core strength translates to poor lower body control, specifically when change of direction occurs. The deadlift (and barbell squat) addresses core strength to a greater extent than conventional “core” exercises (Hamlyn N, 2007) and in addition, the Selective Functional Movement Assessment has created a platform on which to progress core stability from the ground to an overhead squat, for example (clinical confession: although we recognize the lack of evidence supporting this specific application, we find the system one we are able to implement early and believe it does an excellent job of highlighting weak points outside of just the knee!). In short, the SFMA maintains that functional movement is built on developmental layers: rolling supine to prone, prone to supine; quadruped movement, high kneeling stability, and finally, bipedal movement. Gray Cook and the SFMA suggest many protocols or strength programs often skip over the normal developmental progressions and this, in turn, may translate to dysfunctional athletic movement. This protocol incorporates these theories in an attempt to approach core strength as more than sit-ups on a BOSU ball but rather as facilitating and strengthening the core itself on a pattern consistent with our biological development combined with heavy barbell work.

Symmetrical Lower Extremity Activation: Isokinetic testing has long been the norm for measuring lower extremity strength, specifically with return to sport following ACL repair. Consistent decrease in knee extension values are shown as far as 12-24 months after surgery (Xergia SA, 2013 Mar) suggesting

current quadriceps-specific directed therapeutic exercise is falling short. The problem with this type of testing, in our opinion, is that it is single-joint and as such, its predictive implications on athletic movements and the multi-joint systems they require may be over-stated. Additionally, access to the extremely expensive Biodex units the research is performed on may limit accessibility to smaller clinics. That being said, it is important to establish an objective quadriceps/hamstring ratio as this has been suggested to be continued risk factor for re-injury for Return to Sport (RTS) athletes (Kyritsis et al., 2016, Knapik et al, 1991). While the single-leg hop test offers a more complete picture of return to sport deficits in the ACLR athlete, specifically decreased knee flexion angles in load production and increased plantar flexion angles in load absorption (Xergia SA, 2013 Mar), again current rehab protocols may not be addressing the complete athlete. We implement the Keiser Leg extension/flexion machines that rely on pneumatic resistance and provide objective work outputs to establish these ratios. Compound multi-joint training with an objective measure on individual leg output may address the above-mentioned deficits with return to sport and is another testament to the multi-factorial approach it takes for comprehensive ACLR management.

Workload Capacity: One of the most overlooked components in ACL rehabilitation is the establishment of load capacity. Too often the decision for Return to Sport (RTS) is based entirely off subjective reporting of the athlete and time from surgery. While it has been established that the risk of re-injury decreases by 50% for every month the decision to clear an athlete is delayed after the 6-month mark (Grindem et al., 2016), more and more evidence is emerging that the RTS decision is far more complex than that. For this protocol, we will focus on the components we can influence or modify; the non-modifiables such as gender, sport-specific risks, exposure, etc. should be considered as well.

Acute:Chronic ratio establishment has recently been gaining traction in the re-injury risk conversation and while it applies directly to ACL rehabilitation, (Blanch. P, Gabbett. T, 2015) we also feel it is the foundation of all non-contact injuries whether they be muscle strains and re-strains, tendinopathy or even osteoarthritis. Exceeding the load capacity beyond the levels these specific structures have adapted too over time has been well documented in the degenerative cascades seen in tendinopathy (Cook et al., 2015). Essentially, the Acute:Chronic ratio is an objective number comparing the athlete’s chronic workload (in this article, the previous 4 weeks although we feel it can be applied to months or even years) to an uptick in volume over a much shorter period of time (e.g. current week). Gabbett et al. established that a ratio greater than 1.5 significantly increases an athlete’s risk for re-injury. This concept integrates seamlessly with our RTS programming as Return to Sport must be treated as a continuum or a curve rather than a single inflection point.

Over the months prior to an athlete or patient’s projected discharge, these parameters will be determined and progressed accordingly. For example, if we are treating a point guard for the University, we may monitor “minutes played” x “rate of perceived exertion (RPE)” x “frequency”. Weeks 1-4 may be 10 minutes at an RPE of 6, three times per week for example. This would then be a chronic ratio of 10x6x3=180. Week 5 might then be progressed to no greater than 270 which may be broken down as possibly 15 minutes played x RPE 6 x 3/week (270) or even 10 minutes x RPE 7 x 3-4/week (210-280) or further, RPE 9x 10 min x 3/week (270). It is important to note that while week 5 might allow a workload of 270, week 6 is not 270x 1.5 (405) but rather the average of weeks 2-5 (180, 180, 180, 270= 202). Subsequently, week 6 work load would be approximately 300. Although this example utilizes basketball, it can just as easily be applied to weight-lifting, running, or even workplace activity. While it has yet to be studied in this parameter, this concept also serves as our foundation to reducing injuries early in season when athletes return from summer break and likely have not established an appropriate chronic work load for their given sport but that is a conversation for a different protocol!

External Cueing and Jump Mechanics: Additionally, many clinicians have had the displeasure of coaching an athlete or individual for months and observing that while they demonstrate textbook jumping mechanics in the clinic, as soon as they hit the field they often revert to their default programming. After digging into this concept, we have found a wealth of research proposing a mechanism to correct this and it lies in our brains, not our joints (Wulf. 2013). While this is given many names (cerebellar training, reflexive training, CNS facilitation etc.), one thing has become clear: for an individual to truly learn a new movement, it must be coached entirely different. What we have strived to do in this version of our protocol is establish an external focus for an individual when performing a movement rather than an internal focus. How many times have you been told to keep your knee over your 2nd and 3rd toe when performing a step-down? Or to “land with your hips and knees flexed” when jumping? An external locus of focus would be coaching the above movements by telling an athlete to “try and touch the cone when you step down” or to “push the ground away and land soft” when jumping. This maybe a simplification but it is perhaps one of the biggest changes we can implement with our ACL patients to ensure a new movement pattern that may reduce their risk of injury is not only able to be demonstrated in the clinic, but will also show up under duress in a competitive environment (Wulf, G. 2013).

In summary, Nevada Physical Therapy and the University of Nevada-Reno Sports Medicine Department hope to advance the “ACL rehabilitation for athletes” conversation by adding a deadlift progression model to facilitate appropriate hip musculature activation and functional hamstring strengthening while protecting the graft, an evidence-based core/functional movement assessment and exercise prescription consistent with the Selective Functional Movement Assessment, and prioritizing equal lower extremity output during compound multi-joint movements more consistent with strengthening the platforms all athletic movements require. The goal of this rehab model is to improve the athlete to not only their prior level of function but also beyond it as their pre-existing risk factors need to be identified, addressed and corrected.

Bone-tendon-BoneAnteriorCruciateLigamentRehabilitationProtocolforAthletes

CommonRiskFactorsforACLInjury

• HamstringWeakness/DecreasedHamstringtoQuadStrengthratio(>66%formales,>75%forfemales)

• Valguscollapse/PoorJumpingandLandingMechanics

• HistoryofACLinjury(contralateral/ipsilateral)

• CoreWeakness

Pre-OperativeStatus.(21dayspost-op)

“Becauseofthelargeimpactthatquadricepsstrengthmayhaveonkneefunction,theidentificationandtreatmentofquadricepsweaknesspriortoACLreconstructionareparamountinmaximizingpatientoutcomes(AdamsD,2012Mar8.SeealsoTables1and2).”

Theprimarygoalsofthepre-operativepatientareasfollows:

• Decreasekneeeffusionandpaintowithinnormallevels

• ImproveRangeofMotiontouninvolvedlimb

• Normalizegait

• Maximizevoluntaryquadricepscontractionandstrength

TherapeuticExercise

• Wallslides

• IsometricQuadsets/Straightlegraises

• Supinehamstringcurls

• 4-wayhipstrengthening

• Clamshells/lateraltherabandshuffle

• Double-leg/Single-leglegpressasable

PODays1-6:Goals

• ProtectGraftFixation• Controlinflammation.

• Facilitatefullextension• GaitTraining• Rehabprogressioneducation

TherapeuticExercise

• Weightbearingastolerated.• SupineWallSlides,limitedto90°degreesflexionfirst2weeks,130°first4weeks.• QuadSetswithsmalltowelunderknee• 4-wayankleTheraBandstrengthening• Hipabductionifabletoachieveappropriatequadcontraction• StandingHamstringcurlsifnopainreported• BloodFlowRestriction(BFR)implementationastolerated

EndofWeek AROM: PROM:1 0-80° 0-90°2 0-105° 0-1203 0-120° 0-125°

Weeks2-4Goals

• Continuetofacilitatenormalgait.• VMOactivationimprovement/NormalizeStraightLegRaise• Avoidkneeovertoesinallclosed-chainexercises.• Donotprogressflexiongreaterthan125°• Weight-bearingexercisesshouldonlybeprogressedonceadequatequadfunctionisrestored.• NormalizePatellaMobility

TherapeuticExercise

• BikeasROMallows,useforROMfacilitationifflexionlessthan100°• Straightlegraiseifabletoperformwithnoextensorlag

o Begincorecuework,TA/obliqueactivationinconjunction• 4-wayhipstrengthening

o AvoidlaxVMOactivationwithaccessoryplanes(abd,add,ext)• Bilateralbalance/weightshiftwork.• StandingTerminalKneeExtension• Single-legbalancework,progressasable• HamstringbridgingifROMpermits• Double-legsquats0-30°• Stoolscoots• Step-ups/downs(week3-4)withattentiontominimalanteriortranslationoftibiaovertoes.• LateralGaitProgressions(Hurdlestepover,bandedstepover,etc.)• LateralAgilities,bandaroundknee

SFMA/AccessoryWork:

• Initiateupperextremity(2x1)rollingpatterns• Assisted(2x1)hipflexionwithSLR• Assistedhamstring/glutebridge(2x2)asappropriate• AssistedSquatanddeadliftpatternsasappropriatewithROMlimitations• McGillSit-upswithconcurrentquadset,OverheadTAdrills

Weeks4-8Remember:Progressionstoweightbearingactivitiesshouldcomeonlyafterfullextensionandadequatequadfunctionhavebeenachievedalthoughletclinicalpresentationdictateprogressions.

Goals

• Decreasekneepainandeffusion.• ROMwithinNormallimits • Goalsasabove.

TherapeuticExercise

• Asabove,progressedasappropriate• ContinueBFRprogramming,beginlegpressprogressions.• Single-legsquats0-45°withforwardtrunkflexion.• GoodMornings,HipHingepatterns(BPTB)• SinglelegRomanianDeadlifts(withtrunkflexion)withcantouch,progressweightas

appropriate• KBRomanianDeadlifts,avoidanteriortibialtranslationasmentioned• Single-legbalanceworkwithexternalstimuli

• Maybeginswimming(week6),avoidwhipkickSFMA/AccessoryWork:

• Quadrupedworkasappropriate• Bridgeprogressions.• LowerExtremityrollingpatterns

Weeks8-12Goals

• Progressgaittoincludestair-climbing• Increaselowerextremitystrength,DischargeBFRprotocol.• Increaseproprioception,reactiveprogressions• Optimizeforceproduction/absorption• BeginPowerPhase(2-daysplit,HipDominantvsKneeDominant)

TherapeuticExercise

• Progressivebikeresistance/intensity• KneeDominantDay:Front/GobletKBsquats,lungeprogressions,step-upheightetc.• HipDominantDay:DoubleLegRDLs,SingleLegRDLs,SidePlanks,Elevated/Rack/BoxBarbell

Deadliftsasappropriate• NordicTrak/Elliptical• Initiatelaterallungework,attentiontolimittibiaovertoes• Progressprevioustherapeuticexerciseabove• Beginpoolrunning(10-12weeks)• Lightlegsledplyometrics(30%ofbodyweight)

SFMA/AccessoryWork:

• Progressabove• Initiatekettlebelltop-downdeadliftpatternsbyweek4-6ifBPTB,laterifHSgraft

Month3-4ProgressionCriteria:

• Nopatella-femoralpain• 0-120degreesofmotion• Sufficientstrengthandproprioceptiontoinitiaterunning.• Minimalswelling/inflammation.

Goals

• FullRangeofMotion• Beginlightsport-specificstrengthtraining,seejumpprotocol

• ContinuePowerPhase,Strength70%ofuninvolvedlowerextremity.• Avoidunnecessarygraftstrain.

TherapeuticExercise

• Asabove• Legpresstotolerance• InitiateBarbellSquatProgressions(Boxsquat->lowbar->Highbar->FrontSquat)• Beginswimming• Advancedproprioceptionexercises.• BeginJumpProtocolifpatientisabletocompletegreaterthan15singlelegboxsquatsto

parallelwithminimalvalguscollapse.NOTE:Blocksare2-4weeks,3-6repsx3-6sets,3x/week.

CriteriaforProgression:Noincreaseinswelling,nopain,nosubjectivecomplaintofmechanicalsymptoms.Athletemustbeabletocontrollanding,normalizedjumpmechanics:hipandkneeflexion,valguscorrection,etc.

Block1 Nogravity(jumptoelevation,stepdown)Day1 Day2 Rest Day4 Day5 RestBox-Jumps SLBoxHops Recovery SLLateralJump LateralBoxHops Recovery3-6sets,3-6reps,Blockis2-4weeks

Block2 GravityIntroductionDay1 Day2 Rest Day4 Day5 RestHurdleJump SLHurdleHop Recovery SLLateralLineHops LateralHurdleHops Recovery3-6sets,3-6reps,Blockis2-4weeks

Block3 Gravity/Elastic(beginsecondarymovementintorduction)Day1 Day2 Rest Day4 Day5 RestHurdleJumpAcc. SLClockJump Recovery SLSkiHopProgression SLHurdleHop(Multi) Recovery3-6sets,3-6reps,Blockis2-4weeks

Block4 SportSpecific(beginsporttraining)Day1 Day2 Rest Day4 Day5 RestHurdleJumpAcc. SLClockJumpw.Rotation Recovery SLSkiHopProgression SLHurdleHop(Multi) Recovery3-6sets,3-6reps,Blockis2-4weeks

SFMA/AccessoryWork

• Frontplanks/Sideplankprogression• HighKneelChops/Lifts• Kettlebellboxstepdowns/upsfromplyobox• Kettlebellrackwalks/corework/suitcasecarry

Months4-6Goals

• Symmetricperformanceofbasicandsportspecificagilitydrills• Singlehopand3hoptests85%ofuninvolvedlowerextremityat6monthspost-op(ifableto

demonstrategreaterthan90%uninvolvedlegstrengthsymmetry)• Quadriceps/Hamstringstrengthatleast85%ofuninvolvedlowerextremity• EstablishChronicWorkloadparameters(4-6weeksAccumulationPhase)• Phase3Progression(ContinuedPowerprogressions,sport-specifictraining)

TherapeuticExercise

• AgilityProgressionso Sidesteps/crossovers/shuttlerun/singleleganddoublelegjumpingo Ladderdrills/acceleration/decelerationsprints

• Sideplankprogressions• Beginlevel-groundrunning(seeprogression/sorenessmodels)• ContinueBarbellSquat/DeadliftandSingleLegPatterns

Months6-ReturntoSport

• Continuebarbellsquatanddeadlifttrainingo Patientshoulddemonstrategreaterthan75%ofuninvolvedlimbbymonth7as

measuredbyKeiserMachines/Biodex.o Patientshoulddemonstrategreaterthan85%ofuninvolvedlimbbymonth8as

measuredbyKeiserMachines/Biodex.o SingleHop(singlehop.Crossoverhop,triplehop)testinggreaterthan85%of

uninvolvedlimbbymonth9.• JumpProgressionswithexternalcueingfocus,fatigueprotocols,progressingsingle-legand

changeofdirectiontasks.• Acute:Chronicratioshouldbenear75%ofin-seasonworkloadbyendofmonth8.

AdditionalConsiderations:

AthleteProgressionTimeline

Weeks1-8(OrUntilPhase1goalsAchieved)

NevadaPhysicalTherapy

Weeks9-16 Co-treatNevadaPT/SportsMedicine

(monthlycheck-upswithNVPT)

Weeks17-24 NevadaSportsMedicine/Strength

(monthlycheck-upswithNVPT)

Months6-9 UNRStrengthandConditioning

(monthlycheck-upswithNVPT)

Table1SorenessRules*

Sorenessduringwarm-upthatcontinues 2daysoff,dropdown1level

Sorenessduringwarm-upthatgoesaway Stayatlevelthatledtosoreness

Sorenessduringwarm-upthatgoesawaybutredevelops 2daysoff,dropdown1levelduringsession

Sorenessthedayafterlifting(notmusclesoreness) 1dayoff,donotadvanceprogramtothenextlevel

Nosoreness Advance1levelperweekorasinstructedbyhealthcare

professional

*ReprintedwithpermissionfromSAGEPublications:FeesM,DeckerT,Snyder-MacklerL,AxeMJ.Upperextremityweight-trainingmodificationsfortheinjuredathlete.Aclinicalperspective.AmJSportsMed.1998;26(5):735.Copyright©1998SAGEPublications.

Table2RunningProgression*

Level1 0.1-miwalk/0.1-mijog,repeat10times

Jogstraights/walkcurves(2mi)

Level2 Alternate0.1-miwalk/0.2-mijog(2mi)

Jogstraights/jog1curveeveryotherlap(2mi)

Level3 Alternate0.1-miwalk/0.3-mijog(2mi)

Jogstraights/jog1curveeverylap(2mi)

Level4 Alternate0.1-miwalk/0.4-mijog(2mi)

Jog1.75laps/walkcurve(2mi)

Level5 Jogfull2mi Jogalllaps(2mi)

Level6 Increaseworkoutto2.5mi

Increaseworkoutto2.5mi

Level7 Increaseworkoutto3mi

Increaseworkoutto3mi

Level8 Alternatebetweenrunning/joggingevery0.25mi

Increasespeedonstraights/jogcurves

*Progresstonextlevelwhenpatientisabletoperformactivityfor2miwithoutincreasedeffusionorpain.Performnomorethan4timesin1weekandnomorefrequentlythaneveryotherday.Donotprogressmorethan2levelsina7-dayperiod.Conversion:1mi=1.6km.ReprintedwithpermissionfromTaraManal,UniversityofDelawarePhysicalTherapyClinic.

ReturntoSportCriteriaforDivisionIathletes:

Dr.FreddieFurecentlypresentedMRIstudiesdocumentinggrafttypehealingratesandmakestheargumentthatearlyreturntosportclearanceshouldbesupportedbyimagingtosupportanadequatelyhealedgraft.Thebelowimagesweregiveduringarecentwebinar(FreddieFu,MD,2014):

Keepingthisnewinformationongrafthealingratesandtheabovetimelineprogressioninmind,weareabletoformamorecompletereturntosportmodel.ThefollowingparametersuseestablishedreturntosportbaselinesaswellasgoalsuniquetoNevadaPhysicalTherapyandtheUniversityofNevada-RenoSportsMedicineDepartment.

ItemizedReturntoSportTestingList:(Pass,Fail,riskdescription)

1)QuadGirth.PASS/FAIL:PersistentquadricepsstrengthhasbeenlinkedtopoorReturntoSporttesting;“QF strength deficits predicted hop test performance beyond the influences of graft type, presence of meniscus injury, knee pain, and knee symptoms.”(Scmittetal.,2012)(Knapiketal.,1991)

2)ValguswithJumpingTasks,PASS/FAIL“kneeabductionmoment,whichdirectlycontributestodynamiclowerextremityvalgus,wasasignificantpredictorforfutureACLinjuryrisk”(Hewettetal.,2005)

3)CoreWeakness,PASS/FAILDecreasedSingleLegSquatand/orDecreasedSidePlank/LateralChainStrengthmaybepredictiveofACLre-injury(Hegedusetal.2016)

4)Quad:HamstringRatio,PASS/FAILResearchsuggestsdecreasedquadricepstohamstringstrengthmaybeapredictorforACLre-injury(Knapiketal.,1991)and“forevery10%decreaseinthehamstringtoquadricepsstrengthratiotherewasa10.6timeshigherriskofsustaininganACLgraftrupture(Kyritsisetal.,2016)

5)IKDC,PASS/FAIL.“reducedIKDCscoredistinguishpatientswhoareunabletoreturntopreinjurysportsparticipationbecauseoffearofreinjury/lackofconfidence”(Lentzetal.,2015)

6)Single,TripleHop.PASS/FAIL;Decreasedsingleandtriplehoptestingiscorrelatedwithincreasedriskofre-injury.(Kyritsisetal.,2015)

7)AnteriorY-BalancePASS/FAIL;Athleteswhohadagreaterthan4cmdifferenceinanteriorY-balancescoresat12weekswereshowntonotachieve90%orgreaterlowerlimbsymmetryatreturntosporttesting.(Garrisonetal.,2015)

8)T-test,PASS/FAIL;DecreasedT-testspeedscomparedtonormativedataareassociatedwithincreasedACLre-injury.(Kyritsisetal.,2015)

9)ChronicWorkloadEstablished,PASS/FAIL“whenanathlete'strainingandplayingloadforagivenweek(acuteload)spikesabovewhattheyhavebeendoingonaverageoverthepast4weeks(chronicload),theyaremorelikelytobeinjured”(Gabbettetal.2015)“tendonsareatlowestriskwithconsistentworkloadsandsusceptibletoinjurywithsuddenupgradesinworkload”(Orchardetal.,2015)

10)CompleteNevadaPTReturntoSportTesting,PASS/FAIL.CompletingtheestablishedReturntoSportCriteriadetailedabovemaydecreasere-injuryby84%(Grindemetal.,2016)andhasbeenshowtofacilitatea4xhigherrateofreturntoeliteathletics(Kyritsisetal.,2015).

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