We have the injury prevention exercise programme, but how well do youth follow it?

(1)

ContentslistsavailableatScienceDirect

Journal

of

Science

and

Medicine

in

Sport

jo u rn al h om ep a g e :w w w . e l s e v i e r . c o m / l o c a t e / j s a m s

Original

research

We

have

the

injury

prevention

exercise

programme,

but

how

well

do

youth

follow

it?

Nirmala

K.P.

Perera

a,b,c,d

_,

_Martin

_Hägglund

a,b,∗

a_Division_of_{Physiotherapy,}_Department_of_Medical_and_Health_Sciences,_Linköping_University,_Sweden b_Sport_Without_Injury_ProgrammE_(SWIPE),_Linköping_University,_Sweden

c_Centre_for_Sport,_Exercise_and_{Osteoarthritis}_Research_Versus_Arthritis,_Nufﬁeld_Department_of_{Orthopaedics,}_{Rheumatology,}_and_{Musculoskeletal}_Sciences,

UniversityofOxford,Oxford,UnitedKingdom

d_School_of_Allied_Health,_Human_Services_and_Sport,_Latrobe_University,_Melbourne,_Victoria,_Australia

a

r

t

i

c

l

e

i

n

f

o

Articlehistory:

Received24May2019

Receivedinrevisedform5November2019 Accepted13November2019

Availableonline18November2019 Keywords:

Youthsports Sportsinjuries Neuromusculartraining

Injurypreventionexerciseprogramme Floorball

Kneecontrol

a

b

s

t

r

a

c

t

Objectives:DescribetheexercisefidelityandutilisationfidelityoftheKneeControlinjuryprevention exerciseprogramme(IPEP)inyouthfloorballalongsideaninterventionRCT.

Design:Observationstudy

Methods:20floorballteamtraininggroups(12male,8female,age12–17years)fromtheintervention armofanRCTwereincluded.TheKneeControlIPEPwasimplementedatthebeginningoftheseason.A researchteammemberattendedateamtrainingsessiontwiceintheseason(firstandsecondhalfof26 weekseason)withatotal31trainingsessionsobserved.AnIPEPspecificexercisefidelitychecklistwas usedtoassesshowtheprogrammewasused.

Results:Of535individualKneeControlexercisesobserved(76%ofobservationsinmales),58%were per-formedcorrectly.Exerciseﬁdelitywashigherinfemalesthaninmales(71%vs54%,proportiondifference 16%,95%CI7–25%,P=0.001).ThefullKneeControlIPEP(7exercisesx3sets)wascompletedonlyduring 4of31(13%)trainingsessionsobserved.Theutilisationﬁdelitydidnotdifferbetweensexes,andthe meannumberofcompletedexercisesperformedduringtheobservationswas11(SD5).

Conclusions:TheexercisefidelitytoanIPEPinyouthfloorballplayerswaslow,withonlythreeoutof fiveexercisesperformedaccordingtoinstructions.Furthermore,onlyhalfoftheIPEPexerciseswere executedonaverage.TomakeIPEPseffectiveinyouthfloorballandothersimilarteam-ballsports,more workisneededtounderstandthereasonsforlowexerciseandutilisationfidelity.

Practicalimplications

• Exerciseandutilisationﬁdelityareimportantfactorsthat

con-tribute to the effectiveness of an injury prevention exercise

programme(IPEP).Theexerciseﬁdelitywaslow,withonlythree

outofﬁveexercisesperformedaccordingtoinstructions.

Utili-sationﬁdelitywasalsolow,withonlyhalfoftheIPEPexercises

beingexecutedonaverage.ThepreventiveeffectofpotentIPEPs

suchasKneeControlcouldthusbehamperedbylowﬁdelity.

• Identifyingreasonsforlowexerciseandutilisationﬁdelityand

exploringstrategiestobettersupportplayersandcoachesmay

furtherimprovethepositiveoutcomesoftheKneeControlIPEP

andothersimilarprogrammes.

∗ Correspondingauthor.

E-mailaddress:martin.hagglund@liu.se(M.Hägglund).

• Over90%ofcoachesbelievedthatﬂoorballinjuriescanbe

pre-vented,butonlyoneinthreecoachesperceivedtheirknowledge

aboutinjurypreventionasgood.Oneoutofthreecoachesthought

thatregularuseofanIPEPmayactuallyincreaseinjuryrisk

sug-gestingthiskeystakeholdergrouphavegapsinknowledgeand

believesrelatingtoinjurypreventionandeffectsofIPEPs.Assuch

currentdeliverystrategiesofIPEPsincludingKneeControlmaybe

insufﬁcientfortranslatingnewevidencetothisgroup.

1. Introduction

Recentepidemiologicaldatahavedemonstratednoreduction,

orevenincrease,inkneeinjuriesincollegiateathletes1_despite_a

largebodyofevidencesupportingtheefﬁcacyoflowerlimbinjury

preventionprogrammes.2–4_Adherence_to_injury_prevention

exer-ciseprogrammes(IPEP)intermsof performingtheexercisesas

prescribed,withcorrecttechniqueandwiththeprescribedvolume

islikelyakeyaspecttoreduceinjuryrisk.Forinstance,youthfemale

https://doi.org/10.1016/j.jsams.2019.11.008

(2)

soccerplayerswhowerehighlyadherenttoIPEPexercisesreported

ahigher (88%)ACLinjury reduction,while therewasno

differ-enceinACLinjuryratesbetweenplayerswithlowestadherence

andthoseinthecontrolgroup.5_Therefore,_high_exercise_ﬁdelity

(i.e.performingexercisesaccordingtoinstructions)andutilisation

ﬁdelity(i.e.performingallexercisesinanIPEPprogrammewith

theprescribednumberofsetsandrepetitions)isavitalaspectof

adherenceandcrucialtoincreasetheeffectivenessofanIPEP.6–8

KneeControl(Knäkontroll®_,_SISU_{Idrottsböcker©,}_Sweden,₂₀₀₅₎

isaSwedishIPEPdevelopedforteamsports(e.g.soccer,ﬂoorball,

handballandbasketball)andevaluatedinarandomisedcontrolled

trial(RCT).3 _The_real-world_impact_of_the_Knee_Control_IPEP_was

evaluatedusingtheReachEffectivenessAdoptionImplementation

Maintenance (RE-AIM) framework9 _in _a _{questionnaire} _survey

amongyouthsoccercoaches.ThreeyearsaftertheKneeControl

IPEPRCT,91%ofyouthsoccercoaches(notpreviouslyincluded

inthetrial)ineightregionaldistrictsincludedinthestudyknew

abouttheprogramme.Ofthesecoaches,74%hadadoptedthe

pro-gramme,and35%implementeditasprescribed.10_{Hypothetically,}

thedemonstratedeffectivenessoftheKneeControlIPEPcouldthus

fallfroma64%reductionofACLinjuriesinacontrolledsetting3_to

a12%reductioninthereal-worldcontext11_(i.e._64%_{effectiveness}

intheRCTx91%reachx74%adoptionx35%implementation,and

x 82% maintenance). Consequently, with poorimplementation,

potentIPEPsthathavehighreachandadoption,failtoachieve

opti-malimpactintherelevantsportssetting.Inarecentnation-wide

follow-upoftheeffectivenessoftheKneeControlIPEPinSwedish

soccer, a 13% decrease of cruciateligament injuries in females

and6%inmaleswasseen5years afterthenation-wide

imple-mentationoftheKneeControlIPEPcomparedto5yearspreceding

implementation.12_Such_data_give_a_strong_impetus_to_understand

determinantsofexerciseandutilisationﬁdelitytoimproveIPEPs

in order to achieve large-scale and sustained impact beyond

anRCT.

The exercise and utilisation ﬁdelity of IPEPs is rarely

eval-uated alongside an RCT. Further, there is a lack of research

intounderstandingimplementationcontextsandprocesses,and

into intervention adaptation including barriers and facilitators

touptakeand maintenanceof IPEPs.13–15 _For _this_reason, _there

hasbeengrowinginterestintheevaluationofinjuryprevention

interventionsinsportsettings.Barriers tothesuccessful

imple-mentationoftheKneeControlIPEPincludelowﬁdelityinterms

ofcoachesmodifyingtheprogrammetoﬁttheneedsoftheirteam

andplayers,sporadicuse,ordiscontinueduse.10_To_test_the

gener-alisabilityoftheKneeControlIPEPpreventiveefﬁcacyinotherteam

ballsportsthansoccer,asecondclusterRCTwasconductedinthe

2017–18seasoninyouthﬂoorball.Amorein-depthevaluationof

theimplementationoftheKneeControlIPEPintheﬂoorballRCT

couldprovideinsighttoinformevidence-basedstrategiestobetter

targetandsupportimplementation.Therefore,weaimtodescribe

exerciseﬁdelityandutilisationﬁdelityoftheKneeControlIPEPin

youthﬂoorballplayersalongsideaninterventionRCT.

2. Methods

The15-mincoach-ledKneeControlIPEPcontainssixexercises

thattargetcoreandlowerlimbstrength,neuromuscularcontrol,

balance,jumping,andlandingtechnique.Toallowexercise

pro-gressionandvariation, eachexercisehasfourdifferentlevelsof

difﬁcultyandonecorrespondingpartnerexercise.Coacheswere

instructedtousetheprogrammeintheirwarm-uptoalltraining

sessionsandmatchesduringthe26weekseason,startingatthe

easiestlevelandprogressingasplayers’strength,balance,

neuro-muscularcontrolandtechniqueimprove.

Thisobservationalstudy ispart ofthe SportWithoutInjury

ProgrammE(SWIPE)ﬂoorballproject,anRCTevaluatinginjury

pre-ventionefﬁcacyoftheKneeControlIPEPinyouthﬂoorball.Youth

ﬂoorballteamsthathadnotusedtheKneeControlIPEPor

sim-ilarstructuredIPEP,in theyearprecedingtheRCT,and trained

at least twiceweekly, were eligiblefor participation. It should

benotedthatdespitethisexclusioncriteria,42%ofplayers(56%

femalesand39%males)hadpreviousexperiencefromusingthe

KneeControlIPEPduringthepastyearwhentheyparticipatedin

othersports.16_The_intervention_group_coaches_plus_1–2_players

perteamfromclubsintworegionsofSwedenwereinvitedtoa

45-60-minuteseminar(implementationsession)atthebeginning

oftheﬂoorballseason(September2017).Duringthe

implemen-tationsession, coachesreceivedpractical instructions aboutthe

correct executionof each ofthesix exercises (oneleggedknee

squat,pelviclift,twoleggedkneesquat,thebench,thelungeand

jump/landingtechnique)intheKneeControlIPEP.Exercisesare

per-formedinthreesetswith8–15repetitionsperset(or15–30sfor

thebench)(formoredetailsaboutexercisesintheKneeControlIPEP

seeRef.3_)._During_the_{implementation}_session,_exercise

progres-sionandkeyperformancetechniquesweredemonstrated.Coaches

wereinstructedtobeginwiththeﬁrstexerciselevel(easiest),and

whentheirplayerscouldperformtheexercisescorrectlywithgood

technique,theycouldprogresstomoredifﬁcultlevelsofthe

exer-cises.Also,theKneeControlIPEPwasmadeavailabletocoachesin

videoformat,andwritteninstructionswithexplanatorytextand

pictureswereprovided.Aftertheinitialimplementationsession,

coacheswereresponsiblefordeliveringtheKneeControlIPEPto

theplayersoftheirteamsduringtheseason.

Thirty-one teams (23 male and 8 female) with 301 players

(194maleand107female) in17clubsparticipatingat

commu-nitylevel were included in theintervention arm of the RCT.16

These, in turn, formed 23 team training groups (some of the

teamswithinthesameclubtrainedtogether),ofwhich20team

traininggroups(12male,8female)werevisitedduringthis

obser-vationstudy.Threeteamscancelledtheirtraining sessionwhen

theﬁdelityobservationwasplannedandowing tologistic

rea-sons(e.g.travel)itwasnotpossibletoreschedule.Meanageofthe

playersincludedintheinterventionarmwas13.6(SD1.1)years

(female13.8years,male13.5years).Amember oftheresearch

group(1physiotherapist,2physiotherapystudentsand1medical

student)whowereallfamiliarwiththeKneeControlIPEPattended

oneteamtrainingsessionintheﬁrsthalf(NovembertoDecember

2017, 12 team visits) and one in the second half (Februaryto

March2018,19teamvisits)oftheﬂoorballseason.Observation

visitswereorganised withthecoachinadvance and the

inter-action between theobserver and the coaches and players was

kepttoaminimumduringthevisit.Toreduceobserverselection

bias,theobserverrandomlyselectedplayersandallocatedwhich

KneeControlexercisetobeassessedfortheirexecution(exercise

ﬁdelityobservation)beforethetrainingbegan.Therefore,players

andcoacheswereunawareofwhichplayersandexerciseswere

assessed.Theobserversassessedtheexercisesperformedas

cor-rectorincorrectusingastandardisedKneeControlexerciseﬁdelity

checklist(AppendixAandcriteriaAppendixB),whichwas

devel-opedandtestedforinterraterreliabilityinyouthsoccerplayers

(Kappa0.800,substantialagreement).17_The_observers_watched_a

completesetofeachexercise(between8–15repetitions)andthe

overallassessmentwasbasedontheperformanceofthefullset.

Forexample,anexerciseobservationwasgradedascorrectifa

playerperformed10outof12repetitionsofanexercisewithgood

technique.Anexercisewasconsideredasperformedcorrectlyif

theobserverscored‘correct’onallcriteriafortheexercise.

Incor-rectperformancewasindicatedbyrecordingof‘incorrect’forone

ormorecriteria.

Duringtheteamtrainingvisit,theobserveralsocollected

infor-mation relating tothe useof theKnee Control IPEP(utilisation

(3)

were performed (before, in the beginning, during, or afterthe

trainingsession),whichexerciseswereperformed,aswellasthe

numberofsetsforeachexerciseandtheoverallnumberof

exer-cisesperformed.Fullutilisationﬁdelitywasdeﬁnedastheteam

performingallsevenexercises(oneleggedkneesquatcountedas2

exercises,1foreachlimb)oftheKneeControlprogrammein3sets,

thusgivingamaximumof21exerciseobservations.

Abaselinesurveyondemographiccharacteristics,injuryrisk

perceptions,knowledgeandattitudestowardsinjuryprevention

wasdistributedtoallparticipatingyouthﬂoorballteamcoaches

beforethestartoftheseasoninOctober2017.Aseven-pointLikert

scalewasusedforthequestionrelatingtoinjuryriskperceptions.

For the analysisresponses of 1–3were groupedas low risk, 4

wasconsideredneutraland5–7weregroupedashighrisk.The

sameseven-pointLikertscaleandgroupingstrategywasusedfor

questionsrelatingtoknowledgeandattitudestowardsinjury

pre-vention.

ThisstudywasapprovedbytheLinköpingRegionalethics

com-mittee(ProjectnumberDnr2017/294-31).

3. Statisticalanalysis

AllstatisticalanalyseswereperformedusingSPSS®_25.0_(IBM

SPSSStatistics2017).Descriptivestatisticswereusedtodescribe

exercise ﬁdelityand utilisation ﬁdelity.As thedata were

non-normallydistributed,aMann–WhitneyUtestwasconductedto

comparedifferences inKneeControl utilisation ﬁdelitybetween

sexes.Achi-squaretestwasusedtocomparegroupproportions

forcategoricalvariablesandproportiondifferenceswith95%

con-ﬁdenceintervals (CI)were calculated. P≤ 0.05 wasconsidered

statisticallysigniﬁcant.

4. Results

Weperformed535individualKneeControlexercise

observa-tions, 409 in male and 126in female players. Of all exercises

observed, 58% (311/535) were performed correctly. Exercise

ﬁdelitywashigherinfemalethanmaleplayers(71%,89/126

obser-vationsvs54%,222/409observations,proportiondifference16%,

95%CI7–25%,P=0.001).Amongtheindividualexercises,ﬁdelity

washighestforlunges(71%)andpelviclifts(69%),andlowestfor

oneleggedkneesquatontheleftleg(46%)(Table1).Therewasno

differenceinexerciseﬁdelityduringtheﬁrst(57%,124/217

obser-vations)andsecond(59%,187/318observations)halfoftheseason,

proportion difference2%,95% CI -7-10%, (P= 0.702).First-level

exercises(LevelA)weremostlyperformedduringbothseasonal

observations.However,forthepelvicliftandthebench,thelevel

ofdifﬁcultyincreasedtoLevelBandCinthesecondhalfofthe

sea-son(Table2).Malesperformedmoreexerciseswithahigherlevel

ofdifﬁculty(n=247,93and59forlevelsA,BandC/D,respectively)

comparedtofemales(n=88,26,and7,P=0.021).

Intermsoftheutilisationﬁdelity,fullcompletionoftheKnee

ControlIPEP(7exercisesx3sets)wasperformedinonlyfour

ses-sions (3maleand 1femaleteams) outof the31team training

session observations.Themean numberof completedexercises

performedwas11(SD5),andtheutilisationﬁdelitydidnot

dif-ferbetweensexes.Thenumberof setsexecutedforeachsingle

exerciseisreportedinFig.1.MostteamsperformedtheIPEPatthe

beginningofthetraining(55%,17/31)orbeforethetraining(42%,

13/31)andonlyoneteamperformedtheIPEPafterthetraining

session.TheKneeControlexercisesweremainlyperformedinthe

sportshallonarubberorparquetﬂoor(87%,n=27)orinnearby

facilities,e.g.hallwayoroutdoors(13%,n=4).

Ofthe39coachesincludedinthisstudy,13%(n=5)werefemale.

Meanagewas46(SD5)years(male47(SD7)andfemale42(SD1)

years).Sixty-ninepercentofcoaches(n=27)hadbasicandhigher

coacheducation,23%(n=9)hadbasiccoacheducationonly,and

threecoacheshadnocoacheducation.Onaveragecoacheshad7

(SD4)years(male7(SD3)andfemale11(SD8)years)experience

coachingﬂoorballteams.Whenthecoacheswereaskedabouttheir

perceptionofriskofinjuryinﬂoorball,42%(n=16)perceivedthe

riskasbeinglow,21%(n=8)wereneutraland37%(n=14)

per-ceivedtheriskashigh.Themajority(92%,n=36)thoughtinjuries

arepreventable,whilst33%(n=13)thoughttheirknowledgeabout

injurypreventionwasgood,33%wereneutral,and33%perceived

theirknowledgeaspoor.Similarly,33%believedthatregularuse

ofanIPEPcoulddecreaseinjuryrisk,33%perceivednoeffecton

injuryrisk,and33%believedtheinjuryriskmayincrease.

5. Discussion

Theprincipleﬁndingsofthestudywerethatbothutilisation

ﬁdelityandexerciseﬁdelityoftheKneeControlIPEPwaslowin

this cohortofyouthﬂoorballplayers.Only halfof theexpected

numberofexerciseswereexecutedintheobservedtraining

ses-sions,andonlythreeoutofﬁveexerciseswereperformedcorrectly

accordingtoinstructions.Inotheryouthteamballsports,asimilar

trendwasobservedwithonly9%ofcoachesperformingtheIPEP

exactlyasprescribed.18_Exercise_ﬁdelity_in_our_study_was_lower

thanthat reportedfortheFootyFirst IPEPinAustralianfootball

players(69%),6_although_that_study_was_not_in_youth_athletes,_but

higherthanthatreportedfromyouthsoccerplayersperforming

theKneeControlIPEP(48%).17_Over_the_past_two_decades,_sports

medicineresearchhasdevelopedeffectiveinterventionsforinjury

preventionin athletes.Thedemonstrated effectivenessof IPEPs

mightnotfullytranslateintolastingreal-worldeffects,11_which

providesastrongimpetustounderstandthedeterminantsof

exer-ciseand utilisationﬁdelitytoachieve large-scaleand sustained

impactbeyondanRCT.However,itwasbeyondthescopeofthis

study to investigate the relationship between exercise ﬁdelity,

actualdosage(utilisationﬁdelity)andinjuryoutcomes.

CoachesandathletesarekeypartofanyIPEPadherence.15_One

ofthechallengesencounteredinapreviousRCToftheKneeControl

IPEPinfemaleadolescentsoccerwasthatteamandplayer

adher-encedeterioratedovertheseason.5_Low_adherence_is_just_one_of_the

majorbarriersevidence-basedIPEPsfacewhentranslatingfroman

RCTina controlledenvironmenttobroad-scalereproductionin

therealworldunderlesscontrolledconditions.19_The

effective-nessofanIPEPdependsonseveralfactors,includingbothexercise

andutilisationﬁdelity.Lowﬁdelity,therefore,couldhamperthe

preventiveeffects ofpotentIPEPssuchasKneeControl.Totruly

makepreventiveinterventionsinyouthsportseffective,weneedto

ensurethattheinterventioniswell-receivedandusedasintended

byplayersandcoaches.Identifyingreasonsforlowexerciseand

utilisationﬁdelityandexploringstrategiestobettersupport

play-ersandcoachesmayfurtherimprovethepositiveoutcomesofthe

KneeControlIPEP.

Coacheswere instructedto start withthe LevelA exercises

(easiest)andthenprogressthroughthevariousexercisedifﬁculty

levelsastheplayersdevelopbettertechniqueand

neuromuscu-larcontrol.However,mostoftheexercisesobservedatboththe

beginningandtheendoftheseasonwereLevelAandB.Coach

self-efﬁcacy(i.e.theirknowledgeandconﬁdence inleading the

exercises for theirplayers)might bea possible explanationfor

thelackofexerciseprogressionandlowexerciseﬁdelityobserved

inourstudy.Althoughover 90%ofcoachesbelieved that

ﬂoor-ballinjuriescanbeprevented,onlyoneinthreecoachesthought

theirknowledge aboutinjury prevention wasgood. In a

previ-ousKneeControlIPEPimplementationstudyinyouthsoccer,some

coachesexpressedaneedformoresupportandeducationasthey

(4)

rea-Table1

ExerciseﬁdelityfortheobservedKneeControlexercises.

KneeControlexercise Performancecriteriafortheexercise Total Males Females

Correct,n(%) Correct,n(%) Correct,n(%)

1A.Oneleggedkneesquat (right)

Fidelityofthewholeexercise 44/81(54) 30/61(49) 14/20(70)

Fidelityofeachcriterion

- Kneeoverfootalignment 51(63) 37(61) 14(70)

- Trunkcontrol 59(73) 40(66) 19(95)

- Stablehip 62(77) 43(71) 19(95)

- Wholefootcontactwithground 72(89) 52(85) 20(100)

- Footpointingforward 73(90) 53(87) 20(100)

1B.Oneleggedkneesquat (left)

- Trunkcontrol 50(62) 33(54) 17(90)

- Stablehip 50(62) 33(54) 17(90)

- Wholefootcontactwithground 69(86) 51(84) 18(95)

2.Pelviclift

- Trunkcontrol 59(83) 41(79) 18(95)

- Hipextension 49(69) 34(65) 15(79)

- Stableknee/s 66(93) 47(90) 19(100)

3.Twoleggedkneesquat

- Uprightpositiontrunk 53(73) 39(66) 14(100)

- Kneeﬂexionto90◦ ₅₀₍₆₉₎ ₅₁₍₉₀₎ ₁₈₍₉₅₎

- Feetpointingforward 65(89) 51(86) 14(100)

- Smoothreturnfromﬂexiontoextension 66(90) 52(88) 14(100)

4.Thebench

- Elbowsbeneathshoulders 59(77) 42(70) 17(100)

- Upperbodyandtrunkstraight 42(54) 30(50) 12(71)

- Forside-bench:oneelbowbeneathshoulder 1/1(100) – 1/1(100)

5.Lunges

- Trunkcontrol 55(72) 37(65) 18(95)

- Stablehip 59(78) 40(70) 19(100)

- Forwardkneeﬂexedto90◦ ₆₉₍₉₁₎ ₅₁₍₉₀₎ ₁₈₍₉₅₎

6.Jumpandlanding

- Trunkcontrol 62(80) 46(78) 16(89)

- Kneecontrol 61(79) 43(73) 18(100)

- Controlledjumpandlanding 61(79) 46(78) 15(83)

- Softlanding 59(77) 44(75) 15(83)

- Footpointingforwardatlanding 70(91) 52(88) 89(99)

son,itmightbebeneficialtoallocatefurthersupporttocoaches onthefieldandprovideopportunitiestoupskillthroughoutthe season,sothatcoachesareconfidentindeliveringtheKneeControl IPEPorsimilarprogrammes.Sincesuchadditionalresourcesand manpowermightnotbeavailableatcommunitylevelyouthsports othermeansofprovidingthissupportthroughe.g.onlineplatforms, mobileapplications,orsocialmediashouldbeexplored.Oneout ofthreecoachesthoughtthatregularuseofanIPEPmayactually increaseinjuryrisksuggestingthiskeystakeholdergrouphavegaps inknowledgeandbelievesrelatingtoinjurypreventionandeffects ofIPEPssimilartotheirpeersinyouthsoccerandbasketball.14,18

AssuchcurrentdeliverystrategiesofIPEPsincludingKnee

Con-trol may be insufﬁcient for translating new evidence to this

group.

Theexerciseﬁdelitywashigherinfemalesthaninmales,which

corroboratepreviousﬁndingsfromyouthsoccer.17 _Still_this_was

surprisingconsideringthatadolescentgirlstypicallydisplaymore

neuromuscularcontroldeﬁcitsduringjump/landingandcutting

tasksthanboys.21,22 _We_speculate_that _a_heightened_awareness

oftheincreasedriskofsevereinjuriesinfemaleathletes,andthe

beneﬁtsofIPEPsinreducinginjuryrisk,mayhavepositively

inﬂu-encedcoachesandplayersinfemaleteams.TheﬁrstKneeControl

IPEPRCTwasperformedinadolescentfemalesandfound

effec-tivetopreventacutekneeandACLinjuries.3_Since_positive_results

of theRCTgained attentionfrom mediaand sports federations

inSwedenitislikelythattheKneeControlIPEPiswellreceived

byfemale athletesandcoaches andthis couldencourage them

tousetheIPEPwithhighﬁdelity.In contrast,the KneeControl

utilisationﬁdelitywashigherinmaleﬂoorballteamsintermsof

thenumberofexercisesperformedandthisalsowarrantsfurther

investigation.

TheSWIPEpreventionRCTincludedonlyyouthﬂoorballteams

thathadnotusedtheKneeControlIPEPinthepastyear.16_Although

thoseteamsthatusedtheKneeControlIPEPwereexcluded,female

playerswhoplayothersports,suchassoccer,mighthaveusedKnee

Controlin thesesports toahigherextentand thereforealready

beingfamiliarwiththeexercises.Baselinedatafromthecurrent

(5)

Table2

LevelofdifﬁcultyfortheassessedKneeControlexercises.

KneeControlexercise Exerciselevel 1sthalfoftheseason(n) 2ndhalfoftheseason(n) Males(n) Females(n)

1A.Oneleggedkneesquat (right)(n=81)

A 25 40 48 17

B 0 3 0 3

C 2 4 6 0

D 1 6 7 0

1B.Oneleggedkneesquat (left)(n=80) A 25 39 48 16 B 0 3 0 3 C 2 4 6 0 D 1 6 7 0 2.Pelviclift(n=71) A 32 21 37 16 C 1 16 15 2 Partner 0 1 0 1

3.Twoleggedkneesquat (n=73) A 21 21 29 13 B 10 20 30 0 Partner 0 1 0 1 4.Thebench(n=77) A 8 0 3 5 B 21 42 53 10 C 0 4 3 1 D 1 0 1 0 Partner 1 0 1 5.Lunges(n=76) A 27 30 41 16 B 0 7 6 1 D 3 2 3 2 Partner 1 6 7 0

6.Jumpandlanding (n=77) A 25 21 41 5 B 3 11 4 10 C 6 8 12 2 D 2 0 2 0 Partner 0 1 0 1

Aeasiestexerciselevel;Dmostdifﬁcultexerciselevel.

Fig.1. NumberofsetsperformedperexerciseoftheKneeControlIPEP(range0–3sets)forfemales(n=11)andmales(n=20)youthﬂoorballteamtrainingobservations.

oneinsixfemaleplayersandoneinninemaleplayershadregularly usedtheKneeControlIPEPwhentheyparticipatedinothersports duringthepastyear.16_Exercise_ﬁdelity_was,_however,_far_from

per-fectamong females,and asmentionedaboveutilisation ﬁdelity

waslowercomparedtomaleteams.Therefore,itisimportantto

identifywaystosupportplayersandcoachestofurtherimprove

exerciseﬁdelity.Also,motivatorsandbarriersfortheKneeControl

IPEPusemightvarybetweensexesandshouldbeconsideredin

futurestudies.

Oneobviouslimitationof anobservational studylikethis is

thatthecoachesandplayerswereawareoftheobserversbeing

presentduringthetrainingsession,thusintroducingobserverbias.

Consequently, coaches might lead the Knee Control IPEP more

conscientiouslythantheyusuallywould, orplayersmighthave

executedtheexercisestoa higherstandardknowingtheywere

beingobserved.However,beingobservedcouldalsohave

intro-ducedmoretensiononcoachesand/orplayersresultinginpoorer

programme andexercise executiondue to,e.g.nervousness.To

limittheobserverimpacttheinteractionwiththeteamwaskept

toaminimumandthecoachesandplayerswerenotawarewhich

speciﬁcplayersandexerciseswerebeingassessed.Another

limita-tionisthatobservationpossibilitiesattimeswerelessthanoptimal

sinceobserverskept‘outoftheway’fromtheplayerstodisturb

(6)

thebestviewofa playertoobserveallthecriteriaforan

exer-cise,forinstance,thekneeoverfootalignment.Anotherimportant

considerationisthatweonlyobservedteams/playersatoneortwo

trainingsessions(eitheronceortwiceintheseason),andwedonot

knowwhethertheseobservationsareatruereﬂectionoftheactual

utilisationandexerciseﬁdelitythroughouttherestoftheseason.

Manyteamshavemorethanonecoach,andsincewedidnotrecord

whichcoachdeliveredtheKneeControlIPEPduringthe

observa-tionvisititwasnotpossibletoanalysethecorrelationbetween

coachfactors(age,sex,knowledgeandexperienceofIPEPs)and

interventionﬁdelity.Finally,itshouldbenotedthatfourdifferent

observerscollectedthedata.However,theKneeControlexercise

ﬁdelitychecklistwaspreviously evaluatedwithhighinter-rater

reliabilityinasimilarcohortofyouthathletes,17_and_it_should_thus

haveminimalimpactontheoverallﬁndings.

6. Conclusion

Ourstudyprovidesinsightintotheevaluationof

implemen-tationoutcomesoftheKneeControlIPEPinyouthﬂoorball.The

exerciseﬁdelitywaslow,withonlythreeoutofﬁveexercises

per-formedaccordingtoinstructions.Furthermore,utilisationﬁdelity

wasalsolow,withonlyhalfoftheIPEPexercisesbeingexecutedon

average.TotrulymakeIPEPseffectiveinyouthﬂoorballandother

team-ballsports,futureworkisneededtounderstandthereasons

forthelowexerciseandutilisationﬁdelity.Evidence-based

strate-giestobettersupportplayersandcoachescanensureIPEPsare

usedasintended,therebyfurtherimprovingthepositiveoutcomes

ofsuchprogrammes.

Financialsupport

TheSportWithoutInjuryProgrammEisfundedbytheSwedish

ResearchCouncil(2015-02414)andtheSwedishResearchCouncil

forSportScience(P2018-0167).NirmalaKanthiPanagodagePerera

wassupportedbyAustraliaAwards—EndeavourFellowshipfrom

theDepartmentofEducationandTraining,AustraliaandCentrefor

Sport,ExerciseandOsteoarthritisResearchVersusArthritis-Sports

Grant(HFR02510).

Contributorship

BothauthorscontributedtoallitemsintheICMJE

contributor-shipguidelines.

Acknowledgements

Theauthorsacknowledgetheparticipatingplayersandcoaches,

GustavLjunggren RPT,MSc, Oskar Kjellander MS, Ida Elm RPT

andAnton SvenssonRPTfor help withthedatacollection, and

the Swedish Floorball Federation for administrative assistance.

TheSportWithoutInjuryProgrammEisfundedbytheSwedish

ResearchCouncil(2015-02414)andtheSwedishResearchCouncil

forSportScience(P2018-0167).

AppendixA. Supplementarydata

Supplementarymaterialrelatedtothisarticlecanbefound,in

theonlineversion,atdoi:https://doi.org/10.1016/j.jsams.2019.11.

008.

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