A real-world examination of progressive imagery delivery in competitive basketball

A real-world examination of progressive imagery delivery in competitive basketball

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Fazel, Fatemeh, Morris, Tony, Watt, Anthony P and Maher, Roy (2022) A real- world examination of progressive imagery delivery in competitive basketball.

Asian Journal of Sport and Exercise Psychology, 2 (2). pp. 106-113. ISSN 2667-2391

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Asian Journal of Sport and Exercise Psychology

journalhomepage:www.elsevier.com/locate/ajsep

A Real-world Examination of Progressive Imagery Delivery in Competitive Basketball

Fatemeh Fazel

^∗

, Tony Morris , Anthony P. Watt , Roy Maher

Institute of Health & Sport, Victoria University, Melbourne, Australia

a r t i c le i n f o

Keywords:

Routine imagery Progressive imagery Retrogressive imagery Self-efficacy Basketball

a b s t r a ct

Effectivedeliveryofimagerytraininghasbeenstudiedforsometime.Recently,researchershavedetermined that,insomecontexts,ProgressiveImagery(PI),inwhichcontentisaddedtotheimageryscriptinphases,can bemoreeffectivethanRoutineImagery(RI),inwhichalltheimagerycontentispresentedineverysessionof animageryprogram.However,mostresearchtodateconsistsoffieldstudies,lackingecologicalvalidity.We examinedtheefficacyofaPIprogrampresentedtohighly-skilledbasketballplayersinleaguecompetitionacross awholeseason,usingaSingle-CaseDesign(SCD).ParticipantswerefivemaleplayersfromDivision1ofthe StateBasketballLeague,whowerepre-testedontheSportImageryAbilityMeasure(SIAM)toensuretheyhad atleastmoderateimageryability.WemonitoredtheirFree-ThrowShooting(FTS)percentageineveryleague matchofthewholeseason.Thefirst4to6matches(PhaseA)gaveastablebaseline.PhaseB,againlasting4 to6matches,involvedimagerythatfocusedonstaticaspectsofFTSmovements.InPhaseC(4to6matches), morecomplexelementsofFTSwereaddedtoimagery,includingteammatesandopponentsoncourt.PhaseD, lastingatleast4matches,introducedimageryofahigh-pressurecontextinwhichtheFTSshotwoulddecide thematch.Attheendoftheseason,eachparticipantwasinterviewedabouthisexperienceswithimagery.We employedvisualanalysisandthesplit-middletechniquetomeasureperformanceandself-efficacy.Onthese measures,allparticipantsimprovedtheirFTSfrombaselinetoPhaseD,althoughtwoperformedbestinPhase C.Participantsreportedfeelingcomfortablewiththechangingphases,althoughonecommentedthathewould havepreferredthehigh-pressureimageryearlier,beforehefacedrealhigh-pressurefinals.WeconcludedthatPI wasaneffectiveinterventionamonghighly-skilledparticipantsoverafullcompetitionseason,whiletimingof high-pressureimageryshouldbetestedpriortocrucialseason-endingmatches.

Introduction

Researchershaveproposedthatimageryeffectivenessisinfluenced byanumberoffactors,includingthemethodusedtodeliverimagery (Cooley et al., 2013).However, themost effectiveimagery delivery methodisyettobedetermined,andresearchersandpractitionersre- mainuncertainaboutwhichmethod theyshouldrecommendtoath- letes.Onetypeofimagerydelivery,referredtoasRoutineImagery(RI;

Fazeletal.,2018),hasbeenusedinmanystudiesandappliedsettings (forareview,seeCooleyetal.,2013).InRI,participantsimaginethe same,usuallycomplex,sceneduringeverysession,withoutanychanges throughouttheinterventionperiod.WhileRIhasbeenshowntobeef- fectiveinmanystudies,researchersandpractitionershavequestioned whetheritisalwaysthemosteffectivewaytodeliverimagerytraining (e.g.,Cooleyetal.,2013;Fazeletal.,2018).

Anothermethodrecentlyusedintheliterature,whichiscalledPro- gressiveImagery(PI;Fazel etal.,2018,is toimplementvariousele-

∗Correspondingauthor.

E-mailaddress:tima.fazel@gmail.com(F.Fazel).

mentsofimageryinaprogressiveway.Inotherwords,inPI,training programsstartwithsimpleimages,fewobjects,andlittleaction,then becomemorecomplexbyaddinginformationinsteps.Similartothis approach,thetermLayeredStimulusandResponseTraining(LSRT)has beenusedbyotherresearchers(Quintonetal.,2014).Thisapproach involvesaddingmorecontentastheinterventionprogressesinlayers.

TherearedifferencesbetweenPIandLSRT.Firstly,LSRTisparticipant- based,whichmeansthatparticipantschoosewhattheywanttoaddto thecontent,whereasinPItheresearchersdeterminethecontentthatis added.Secondly,thenamelayereddoesnotindicatewhetherthecon- tentistakenawayoraddedtotheimageryscript.Fortheabovereasons, wechosePI,asitclearlysuggestscontentisprogressivelyaddedtothe imageryscript.

Oneofthefirststudiesthatgeneratedtheideaofusingdifferentim- agerycontentwasthestudybyCalmelsetal.(2004a),Berthoumieux, andd’Arripe-Longueville(2004).Inthis5-stageimageryintervention, researchersaddedmoreelementstotheimageryscriptstagebystageto makethescenariomorerealistic.Tobespecific,theimagerythatwas

https://doi.org/10.1016/j.ajsep.2022.09.002

Received17May2022;Receivedinrevisedform9September2022;Accepted9September2022

2667-2391/Copyright© 2022TheAuthors.PublishingservicesbyElsevierB.V.onbehalfofKeAiCommunicationsCo.Ltd.Thisisanopenaccessarticleunderthe CCBYlicense(http://creativecommons.org/licenses/by/4.0/)

F. Fazel, T. Morris, A.P. Watt et al. Asian Journal of Sport and Exercise Psychology 2 (2022) 106–113

presentedtosoftballplayersbecamemorecomplexwitheachstageby addingthepositionofpotentialrunnersondifferentbasesandpossible distractions(e.g.,weather,noise,unfairumpire).After28daysofim- ageryuse,participantsshowedimprovementondimensionsofselective attention.Inasimilarstudy,theimageryvividnessofsoftballplayers increasedafterincorporatingfivephasesofimagerytraining(Calmels etal.,2004b).Calmelsetal.(2004b)addedmoredetailsineachstage (e.g.,thetrajectoryoftheball,desiredcontactwiththebat,theweather, andthecrowdnoise),andalsoincludedimageryofdealingeffectively withdistractioninformation(e.g.,thereputationofthepitcher,score, andaperceivedunfairumpire).Calmelsetal.(2004b)foundthisim- agerydeliverymethod,calledPIinthecurrentstudy,topositivelyaffect participants’imageryvividness.Calmels andcolleaguesexaminedPI- styleimageryinterventions,butmainlyfocusedonpsychologicalvari- ables,suchasimprovementinvisualperception,imageryability,and self-efficacy(Calmelsetal.,2004a,b;Williamsetal.,2011)andtheydid notexaminetheeffectofsuchimageryonperformancedirectly.How- ever,theirstudieshavebeencriticisedbecausetheyinvolvedsmallsam- ples(N=4)andfornotemployingacontrolcondition(Williamsetal., 2013).

Another study that examined LSRT was the study by Williams et al. (2013). In this study, participants were asked to addelementsthattheyfeltwouldmaketheimageryexperiencemore realisticlayerbylayer.Williamsetal.assignedparticipantsintothree different conditions, namely LSRT, movement imagery, and visual imageryconditions. Only participantsintheLSRTcondition showed improvementon theirkinesthetic imageryability, imageryabilityof morecomplexskills,andactualgolf-puttingperformance.

Quintonetal.(2014)examinedthePIapproach,usingtheLSRTap- proach.However,participantswerechildren,andtheimageryaimedto maintaintheirinterest,avoidboredom,andalsotopreventoverload- ingthemwithtoomuchnewinformationatonetime.Quintonetal.

reportednosignificantimpactonchildren’sperformancenorontheir imageryability.However,theeffectivenessofLSRTwasevidentinother studies(e.g.,Marshall&Wright,2015;Williamsetal.,2013).Forexam- ple,Williamsetal.comparedLSRTeffectivenesswithimagerypractice onperformanceandimageryability.LSRTwasfoundtobe effective inperformanceimprovement.MarshallandWrightalsodemonstrated effectivenessoftheLSRTapproachinenhancingperformance.

Athirdtrainingmethod,introducedbyFazel etal.(2018)forthe firsttime,isRetrogressiveImagery(RETI),inwhichtheprocessofPIis reversed,startingwiththecompleximageryscene,thenremovingele- mentstofinishwithimageryofthecentraltask.ThereasonFazeletal.

namedthisimagery deliverymethodRETIis thattheimagerystarts withverydetailedandcomplexscenarios,thenelementsaregradually removedtomaketheimageryscriptsimpler.InFazeletal.,thethreeim- agerydeliverymethods(RI,PI,andRETI)werecompared,alongwith anoimagerytrainingcontrolconditiontoidentifythemosteffective methodinperformanceenhancementandself-efficacyimprovementof athleteswithlimitedskills.ResultsshowedRETItobesuperiortothe otherconditionsforlimited-skillplayersinbasketballfreethrowshoot- ing(FTS)performance,aswellasself-efficacy.Inanotherstudy,Fazel etal.(2022submitted)repeatedallaspectsofthesamestudydesign, butwithhighly-skilledbasketballplayers.TheycomparedRETI,PI,and RI,withanoimagerycontrolcondition.Interestingly,theyfoundthat, withasampleofhighly-skilledathletes,PIwasthemosteffectiveim- agerydeliverymethodforenhancingperformanceandself-efficacy.

Mostof the research that hasbeen conductedon imagery deliv- erymethods hasused laboratory or field-study designs, which have been popularin other research examining imagery trainingin sport (Morrisetal.,2005).However,sportpsychologyresearchersandpracti- tionersstartedtoadoptmoresinglecasedesigns(SCD)becauseofcon- cernsregardingtheecologicalvalidityoflaboratoryandfield-studies (Hrycaiko&Martin,1996).ThenumberofstudiesusingSCDhasin- creaseddramatically,leadingBarkeretal.(2013)topublishaspecial issueonSCDpapersinsportpsychologyintheJournalofAppliedSport

Psychology. Theissueaimedtohighlightthesignificanceof SCDand raise awareness of suchresearch methodsas acredibleapproach in sportpsychology.Experimentalresearchdesignsdonotalwaysfitcom- fortablywiththecharacteristicsofanappliedsetting(Andersonetal., 2002),aslaboratory-based,aswellasfieldstudy,researchcreatesan artificialenvironment,whichoftenbearslittleresemblancetocompeti- tion(Goldfried&Wolfe,1996).Moststudies,likethosebyFazeletal.

(2018,2022underreview)werefieldstudiesinwhichitwaspossibleto controltheschedulingandthenumberofFTSperformedbyeachpar- ticipant.Suchfieldstudiesperformedawayfromtherealcompetition contextexamineperformancein“sterile” situationslackingthestressof competition,aswellasallthecomplicationsrelatedtothepresenceof team-mates,opponents,referees,andspectators.Thus,thefieldstudies byFazeletal.providedonlyapartialtestofhowthedifferentimagery deliverymethodswouldfunctioninhigh-levelcompetition.Inparticu- lar,theydidnotcreateacontexttofullyexaminetheimpactofmany keyfactorsofhigh-levelcompetition(theteam-mates,opponents,ref- erees,spectators,andthepressureofthecompetitioncontext)asthey wereprogressivelyaddedinthePIcondition.

TheprimaryaimofthecurrentpaperusingSCDwastoexaminethe impactofPIonFTSperformanceamonghigh-levelbasketballplayersin leaguematchesacrossawholebasketballseasontoconfirm,challenge, orextendthefindingsofinterventionfield-studies(Fazeletal.,2018, 2022submitted)inarealcompetitioncontext.Nostudyhasexamined theeffectsofanyimagerydeliverymethod(e.g.,LSRTor PI)inreal gamesituationsatahigh-levelofskill.Performancecouldbeaffected differentlyduringhighly-competitivematches,whereteam-mates,op- ponents,officials,andspectatorscanallaffectindividualplayers,aswell asthephysicalenvironment,particularlywhenitisnotthehomecourt (Maheretal.,2019,2020).Inaddition,tounderstandwhatparticipants experiencedoverthatperiodintermsofthePItraininganditsimpact ontheirFTSperformanceincompetition,weinterviewedeachplayerat theendoftheseason.Inthisway,weacquiredmoredetailedinforma- tionregardingwhattheylikedanddislikedabouttheinterventionand itseffectontheirmatchperformancetohelpelucidatethequantitative results.

Materialandmethods Participants

ParticipantsinthisstudywerefivemaleVictoriaStateChampionship League players aged between 28 to36 years (M = 31.8,SD = 3.4) withaminimumexperienceof15yearsplayingbasketball(M=22.2, SD=5.3).Thestatechampionshipleagueisthehighestlevelofmen’s basketballcompetitioninVictoria,Australiaandrankedthirdamong Australianbasketballleagues.Someplayerswithnationalteamexpe- rience,butneartheendoftheircareers,andyoungtalentedplayers competeintheStateChampionshipsLeague.

Participantshadnopreviousexperienceinsystematicimagerytrain- ing.TheydemonstratedtheabilitytoimaginethecontentofthePIin- tervention.Playerswererequiredtohaveaminimumscoreof150out of400onthemostrelevantsubscalesforperformingPI(vividness,con- trol,visual,kinesthetic,tactile,andauditory)oftheSportImageryAbil- ityMeasure(SIAM;Wattetal.,2004).Allparticipantshadaminimum ofsixFTSshotsduringeachgameintheirpreviousplayingseason.

StudyDesign

A multipletreatment(ABCDSCDwas employedtoexamine how addingnewelementstothescriptphasebyphaseinthePIinterven- tionaffectedparticipants’performanceofFTSinmatchesthroughouta competitionseason.Followingthebaseline(A)phase,whichwasano imageryphase,thePIinterventionwasintroducedtotheparticipants progressivelyinthreephases.Duringthethreeinterventionphases(B,C, D),participantsreceivedmorecomplexcontentintheimageryscriptin 107

eachphase.Thus,theinterventionprocessextendedthesimpleABSCD toanABCDdesign,sotheseparateimpactofeachinterventionphase couldbeevaluatedandcomparedwiththebaselinephaseandwithother imageryphases(Kazdin,2011).Eachphaselastedonemonth,whichin- cludedbetween4and8homeandawaygames,andeachparticipant’s FTSwasmeasuredindividuallyineachgame.

Attheendofthestudy,weinvitedallparticipantstotakepartin aninterviewsession.Weconductedanindividualface-to-faceinterview witheachplayerinrelationtosocialvalidationfeedbackabouttheir experiencesofusingPI,andtoobtaintheirestimateoftheeffectiveness ofPIrelatedtocompetitionFTSperformance.Playerswerealsoasked whethertheyhadanysuggestionstoenhancetheeffectivenessofthePI program.

Measures

Demographicinformationform.Wegatheredspecificdetailsre- gardingparticipants’age,gender,yearsofbasketballexperience,and whetherthey had experiencedimagery or other psychological tech- niquesbefore,usingademographicinformationform.

SportImageryAbilityMeasure(SIAM;Wattetal.,2004).Wead- ministeredtheSIAMtoensurethatparticipantshadatleastmoderate imageryabilitytoperformtheimagerytasksintheintervention.Ath- letesimagined each offour sport-relatedscenes, duringa60-second periodfor eachscene. Followingtheimageryperiod foreach scene, athletesrespondedto12items,representingfiveimagerydimensions (vividness,control,easeofgeneration,speedofgeneration,duration), sixsensemodalities(visual,auditory,kinaesthetic,olfactory,gustatory, tactile),andimageryofemotion,byplacingacrosson100mmvisual analoguescaleswithverbalextremesattheendofeachscale(e.g.,“no imageatall” to“perfectlyclearimage” forvividness).Scoresforeach dimensionormodalityweresummedacross thefourscenes,so each subscalescorevariedbetween0and400points.Intheoriginalvali- dationprocess,theSIAMrevealedalpha valuesbetween .66and.87 (Wattetal.,2004).Thescoresofthekeydimensionsubscales(vivid- ness,control)andsensemodalitysubscales(visual,kinesthetic,tactile, andauditory)thatareconsideredtobemostrelevanttobasketballfree- throwshootingperformancewereevaluatedtoensurethatathletes’im- ageryabilitywasadequate(>150outof400)tobenefitfromtheim- agerytraininginthisstudy.

Freethrowshootingpercentage.Weusedthebasketballleague’s statistics regardingparticipants’FTSattemptsandsuccessful FTSfor eachgame.Datawasalsoobtainedfromtheofficialscoresheetsofthe games.Incaseofanydiscrepancybetweenthesetwosources,weused theofficialscoresheetsduetothehighlevelofaccuracyofthisdata recordingsystem.Gamefree-throwpercentages,numberofsuccessful shots,dividedbytotalnumberofattempts,multipliedby100,werecal- culatedforallhomeandawaygames.

Imagerymanipulationcheck. Toverifytheimageryexperience, participantsfilledoutamanipulationcheckform aftereach imagery session.Thischeckfollowedrecommendationspreviouslymadeinthe literature(e.g.,Cumming&Ste-Marie,2001;Nordin&Cumming,2005; Smith&Holmes,2004).Weaskedparticipantstoratehowwellthey saw,heard,felt,andhowwelltheyperformedtheimagerytheywere instructedtodo.Theymaderatingsona4-pointLikertscaleranging from0(notatall)to4(verymuch).

Socialvalidationinterview.Socialvalidationhasbeencommonly usedinSCDstudieswithinsportandexercisepsychologyresearch.As recommendedintheliterature(Page&Thelwell,2013)weusedsemi- structuredinterviewsfordatacollection,usingcontentanalysistoana- lyzethesedata,reportingqualitativesocialvalidationresultsinathor- oughmanner.Attheendoftheinterventionphase,weinterviewedall participantsinone-on-onesessionstoexploretheirpersonalexperiences andacquiremoredetailedinformationregardingthePIinterventionand itseffectiveness.Themainresearchquestionsfocusedonparticipants’

imageryexperience,perceivedeffectsoftheintervention,aspectsofthe

imagerycontentthatwereeasy-hard-useful,howtheyfeltduringthe imageryprocessandduringrealFTSperformanceduringthegame,and iftheirpreparationtoexecuteFTShadchangedduringthecourseofthe season.Theinterviewswereconductedforeachparticipantaweekafter theirfinalgameoftheseason,recordedandtranscribedverbatim.

Intervention

PhaseAwasthebaselinenointerventionphase,duringwhichwe monitoredFTperformanceofathletesforfourtosixgames.Afterbase- linewascompleted,weintroducedthefirstinterventionphase(Phase B)byinstructingathletestoimaginesimplestaticaspectsofthebasket- ballFTcontextduringagame.Playersimaginedcourtlines,therim, andthemselvesstandingatthefoullinesensingthemusclesintheir legsandarms,andperformingFTS.Theyperformedtheimagerythree timesaweekforfourweeks.InPhaseC,weinstructedtheplayersto includemoredetailsintheirimageryscenebyaddingteam-matesand opponentsstandingaroundthebasketballkey,aswellasthevoiceof thereferee,andthenoiseofthecrowd.Thiswasfollowedbythefinal interventionphase,PhaseD,duringwhichweincreasedthecomplexity further.Weinstructedparticipantstoimagineahigh-pressuresituation inwhichtherewasonesecondleftontheclock,theirteamwasbehind byonepoint,andtheoutcomeofthegamedependedontheirFTS.

Procedure

ThestudywasapprovedbytheUniversity’sHumanResearchEthics Committee. Participants read a statement about the purpose of the study,askedanyquestionsaboutwhatwasexpectedofthem,andsigned aninformedconsentform,iftheywerewillingtovolunteer.Weselected StateChampionshipbasketballplayerswhowerelikelytohavesubstan- tialnumbersofFTSsduringmostgamesbylookingattheirFTstatistics fromthepreviousseasonandthefirstthreegamesofthecurrentseason, becausethatisthebestindicatoroftheirstandardwhentheyentered thestudy.Weinvitedthemtoparticipateinthestudybysendingan email tothem. Inthefirstindividualmeeting,followingtheconsent process,asanintroductiontotheconceptofimagery,eachparticipant wasgivenadefinitionofimagery,andwasinformedabouttheeffec- tiveuseofimagerybyeliteperformersinmanysports,withexamples.

Participantswerethengiventheopportunitytoaskquestionstoensure theyunderstoodwhyimageryiswidelyusedbyhigh-levelperformers.

ParticipantsthencompletedtheSIAM,whichreflectstheuseofimagery insixsensemodalities,fivedimensions,andtheexperienceofemotion duringimagery.

WeimplementedaSCDproceduretoassesseachplayer’sFTSper- centageperformanceinallgamesduringtheplayingseason.Toattain astablebaseline,PhaseAvariedbetween4and6games.Thisphase generatedpre-interventiondataforcompetitiveFTS.Theintervention phases(B,C,andD)lastedfor4to6gameseach.Ineachintervention phase,playerslistenedtothedesignatedPIcontentpresentedinmp3 format andsavedon eachplayer’smobilephone, inthreesessionsa weekforfourweeks.Inastudyofnetballshooting,andinastrength task,WakefieldandSmith(2009,2011)reportedthatimagerytraining ismoreeffective,whenitisconductedthreetimesperweek,compared withonceortwice perweek.Asparticipantsinthis studyhadthree sessions ofbasketballtraining eachweek,we decided toassign par- ticipantsthreeimagerysessionsperweek,aftertheirtrainingsessions.

Theseandotherresearchers,includingFazeletal.(2018,2022submit- tedforreview)havechosenfourweeksofimagerytraining,alongwith threeimagerysessionsperweek,andfoundthistobeeffective.Insome weeksduringtheinterventionphase,playershadtwogamesoverthe sameweekend(SaturdaynightandSundaymorning),sotherewasno imagerypracticebetweenthosegames.Thisalsoexplainswhytheim- ageryphaseslastedfourweeks,butthenumberofgamesinthatperiod varied between4and6.Playerswhomadethefinalshadtwoextra gamesinthelastinterventionphase.Thismeansthatoncetheyreached

F. Fazel, T. Morris, A.P. Watt et al. Asian Journal of Sport and Exercise Psychology 2 (2022) 106–113

thefullimagerycontentinPhaseD,theycontinuedtolistentothefinal imageryscriptfortherestoftheseason.Attheendoftheintervention(a weekafterthefinalgameoftheseason),weinvitedallfiveparticipants toattendanindividualinterviewtocapturetheirpersonalexperiences.

Finally,wegaveeachparticipanttheopportunitytoaskanyquestions ormakeanycomments.Afterthisdebriefing,wethankedthemfortheir participation.

Analyses

Weemployedvisualanalysistodeterminedchangesineachpartic- ipant’sFTpercentagetrendfromonephasetoanotherthroughoutthe study.Thevisualinspectionmethodhasbeenwidelyusedtoanalyse thedatafromSCDstudiesbylookingforchangesintrend,level,slope, andvariability(Ximenesetal.,2009).Themaincriteriausedin this studytovisuallyanalysethegraphsofeachparticipantwerechangein themean,changeinlevel,andslopeordirectionofthecelerationline fromphasetophase.Wecalculatedthemeanofeach phasebysum- mingthevaluesofallthedatapointsofeachphaseanddividingthe totalbythenumberofdatapointsinthatphasetocheckwhetherFT shootingperformanceeitherincreasedordecreasedfromtheprevious phase.Wecalculatedtrendlinestoprovideadescriptiveaidforvisual inspectionandallowforlevelandslopemeasurementstobecalculated.

Tocreateatrend,orceleration,lineforthepurposeofexaminingthe resultsin SCDstudies,atechniquecalledtheSplit-middleTechnique hasbeendeveloped(White,1972,1974).Weappliedthesplit-middle techniquetodeterminetrendlinesforeachphaseandtocalculatethe levelandslopeofthelinesforvisualinspectionofthedataasproposed byWhite(1974).Stepsforcreatingatrendlineare,a)drawavertical lineinthemiddleofthedatapoints,sotherewillbethesamenumber ofdatapointsineachhalf.Ifthereisanoddnumberofdatapoints,the linewillbedrawnthroughthemiddlepoint.b)Findthemedianofthe datapointsinthelefthalf,aswellasthemedianofthepointsinthe righthalf.c)Drawaverticallineinthemiddleofeachhalf,soyoudi- videthedatapointsinto4quarterswithanequalnumberofdatapoints ineachquarter.d)Findtheintersectionbetweentheverticallineinthe middleofeachhalfandthemedianofthesamehalf.e)Thetrendline willbethelineconnectingthetwointersectionpoints.

Levelreferstothevalueofthedependentvariablewherethecelera- tionlinepassesthroughtheendofonephase(lastgameinthebaseline phase,PhaseA,forinstance)withthebeginningofthenextphase(first gameinPhase B).Tocalculatethechangein level,thelargerofthe twovaluesisdividedbythesmaller.Thetrendorslopereferstothe directionofsuccessivedatapointswithineachphase,comparedtothe nextphase.Theslopeofthelineforeachphaseiscalculatedbyarbitrar- ilyidentifyingapointonthelinealongwiththepointontheordinate throughwhichthelinepasses(Kazdin,2011).Thelargervalueofthese twophasesisthendividedbythesmallertoderivetheslopeoftheline.

Amultiplicationsign(x)isgiventotheline,ifanincrement(shiftup) occursinlevelaswellasinslope,andadivisionsign(÷)isused,ifa decrement(shiftdown)occurs.

Weemployedinductivecontentanalysistoanalyzethesocialval- idationinterview.Intheinterviews,weaimedtoexploreparticipants’

experienceofimagery,PIinparticular,andtheirattitudetowardsit,and nottodriveanewtheory(Patton,2002).Todoso,wetranscribedthe recordedinterviewsverbatimandcheckedcontentaccuracybyreading thetranscribedinterviewsandlisteningtotheinterviewrecordsseveral times.Rawdatainterviewstatementsweregroupedtoderivethemes relatedtoparticipants’experiencebyreading,rereading,andcoding (knownasopencoding;Patton,2002)andtoensurethatalltheraw statementswerecategorizedintothemost suitabletheme.Toensure reliabilityandtrustworthiness,themethodof triangulationwas used (Patton,1990),inwhichtwoormoreresearchersindependentlyreview andinterpretthesamesetof transcriptsof qualitativedataandthen comparetheirinterpretations,discussingdifferencesuntilconsensusis reached.Todothistriangulationanalysis,weaskedasportpsychology

Table1

imageryabilityscoresofparticipants.

Auditory Visual Kinaesthetic Tactile Control Vividness

Scott 293 232 257 259 286 299

Tom 299 316 244 270 316 306

Jason 250 259 208 206 313 281

Sam 290 382 244 173 256 362

Manny 254 318 232 257 326 287

Table2

Participants’Imagerycheckmeansandstandarddeviationsforthe fourphases.

Participant Phase A Phase B Phase C Phase D

Scott M 3.48 3.54 3.50 3.57

SD .34 .37 .36 .28

Tom M 3.32 3.36 3.46 3.82

SD .56 .40 .37 .10

Jason M 2.82 3.23 3.39 3.35

SD .32 .64 .30 .26

Sam M 2.63 2.80 2.96 2.95

SD .66 .54 .32 .42

Manny M 3.33 3.56 3.87 3.92

SD .48 .32 .06 .04

researcherfamiliarwiththesocialvalidationinterviewanalysisprocess toindependentlyexaminethetranscriptsoftheinterviews.Then,the firstauthormetwiththisresearchertodiscussissuesraisedandresolve disagreementsaboutcoding.Fordetaileddiscussionofthetriangulation processseeSmithandMcGannon(2018)(Table2).

Results

In this study,we examined theeffect of PI trainingon competi- tion FTSperformanceof highly-skilledbasketballplayers.Inthis re- sults section,we present participants’profilesfollowed by their im- ageryscreeningscores, game-by-gameFTSpercentage,andinterview responses.GameFTSpercentageforallfiveparticipantsis illustrated in Fig.1,followedbytheirinterviewresponses.Inparticular,wein- cludeintheinterviewresponsessectionparticipants’explanationsof theirfeelingsduringtheimagerytrainingandduringtheirFTSperfor- manceinareal-timesituation.Wealsoexploredwhetherparticipants’

experiencechangedduringtheseason.Thenamesusedinthissection arepseudonyms.

Participants’profile.Participants’averageagewas30.8years,with anaverageof20years’experienceofplayingbasketball.Theyallplayed atahighlevelofbasketballfromstatechampionshiptonationalrepre- sentation.Allfiveparticipantsplayedanimportantroleintheirteam.

Withrespecttoscoring,theyhadanaverageof22.8pointspergame during thepreviousplaying season.This meanstheywerekeyteam membersintermsofthecorecriterionofpointsscoredinleaguecom- petition.Noneoftheparticipantshadpreviousexperienceinanykind ofpsychologicaltrainingprogram,includingimagery.

ScreeningforImageryAbility.Toensurethatparticipantshadsuf- ficientimageryabilitytobenefitfromthePIinterventionprogram,we measuredtheirimageryabilityusingSIAM.Aminimumscoreof150 outof400onallsixmostrelevantSIAMsubscaleswasrequiredforpar- ticipantstobeeligibleforthisstudy.Imageryabilityofallparticipants onthesixkeysubscalesispresentedinTable1.Ingeneral,allpartic- ipants’imageryabilityscoreswerehighandwellabovethecutoff for acceptanceinthestudy.

Freethrowperformance.SuccessfulFTSpercentageforeachgame forallparticipantswasmeasuredthroughouttheseason.Fig.1a-eshows performanceacrossthefourphasesinthestudy,includingthemean for eachphase,thelevel ofthecelerationline, andtheslope of the celerationlineintothenextphase,forallfiveparticipants.Thisfigure wascompiledtofacilitatecomparisonbetweenparticipants.

109

Fig.1. Split-middleanalysisofparticipants’ftspercentagethroughouttheseason.

Notes: 1.InFigure1,graph(1)isScott;(2)isTom;(3)isJason;(4)isSam;and(5)isManny.

Scott’smeanFTSshootingpercentage(Fig.1a)increasedby16.06%, thelevelshifteddown6%,andthetrendlineincreased(x1.06),during PhaseBcomparedtothebaselinephase(A).IncomparisonwithPhase C(2ndinterventionphase),Scott’sFTS%meandecreased3.56%,the levelshifteddown4.9%,andthetrendlinedecreased(÷1.38).During PhaseD,Scott’sFTS%meanrecoveredby3.74%,approximatelytothe samemeanlevelasPhaseB,thelevelshiftedupby6%,andthetrend linedecreased(÷ 1.09)comparedtoPhaseC.Overall,Scottshowedan improvedFTSpercentagemeaninthesecondphaseandmaintainedthe improvementinPhaseD,attheendoftheseason.

2.Thesolid,bolded,verticallinesindicatethepointofphasechange, horizontaldashedlinesrepresentmeanperformanceforeachphase,and dottedlinesineachphasesignifycelerationlines.

3. Thesymbol Nin this figure indicates that no free throw was awardedtotheplayerduringthatgame.

Tom’sFTSpercentagemean(Fig.1b)increasedby2.84%,thelevel shifteddown8.3%,andthetrendlineincreased(x1.51)duringPhaseB comparedtothebaselinephase.Tom’sFTSpercentagemeanincreased furtherby11.07%,however,thelevelshifteddownby10.4%,andthe trendlinedecreased(÷1.39)duringPhaseCcomparedtothePhaseB.

DuringPhaseD,performanceimprovedby4.57%,thelevelshiftedup 14.5%,andthetrendlinedecreased(÷1.10)comparedtoPhaseC.In summary,Tom’sFTSshootingimprovedingradualstepsthroughthe phases.HisFTSpercentagemeanduringthebaselinephasewas52.37, and,aftertheimageryintervention,heimprovedhisFTSpercentageto 70.85.

InrelationtoJason’sperformance,hisFTSpercentagemean(Fig.1c) showed4%improvement,thelevelshifteddown5.5%,andthetrend linedecreased(÷ 1.32)duringPhaseBcomparedthebaselinephase.

During Phase C, Jason’s FTS percentage dramatically increased by

F. Fazel, T. Morris, A.P. Watt et al. Asian Journal of Sport and Exercise Psychology 2 (2022) 106–113

20.15%,thelevelshifteddownmarginally2%,andthetrendlinein- creased(×1.60)comparedtoPhaseB.InPhaseD,Jason’smeanperfor- mancedecreasedby5.67%,thelevelshifteddown45%,andthetrend linedecreased(÷ 1.26)comparedtoPhaseC.Overall,Jason’smean performanceincreasedin PhasesB andC.Even thoughperformance droppedalittleinPhaseD,therewasstillabigimprovementcompared tothebaseline.Jasonstartedwith61%FTSshooting,duringthebase- linephase,andhisFTSperformanceincreasedto85.15%inPhaseC, andJasonfinishedtheinterventioninPhaseD,withFTSperformance of79.48%,alargeincreasefromthebaselinephase.

FromthevisualinspectionanalysisofSam’sperformance(Fig.1d), specificallyduringPhaseB,theFTSpercentagemeanimprovedslightly by7.50%,thelevelshifteddown14.4%,andthetrendlineincreased (x1.00)comparedtothebaselinephase.During PhaseC,thesecond interventionphase,Sam’sperformancemeanincreasedsubstantiallyby 21.05%,thelevelshiftedupmarginally 0.6%,andthetrendlinein- creased(x1.09).InPhaseD,hisFTSpercentagedeterioratedby14.39%, thelevelshifteddownby16%,andthetrendlinedecreased(÷ 1.08) comparedtoPhase C.Overall,Sam’s improvementshowedasimilar patterntothatdemonstratedbyJason.HeshowedimprovementinFTS percentagemeaninPhasesBandC,withaverylargeimprovementin PhaseC,butFTSperformancedeclinedinPhaseDcomparedtoPhase C.However,Sam’sperformanceinPhaseDwasgreatlyimprovedcom- paredtoPhaseA,thebaseline,witha14.16%increase.

Basedonthesplitmiddleanalysis,Manny’smeanFTSpercentage performance(Fig.1e)improvedby8.4%,thelevelshiftedup3.9%,and thetrendlinedecreased(÷ 1.02)inPhaseBcomparedtothebaseline phase.Manny’smeanperformanceinPhaseCincreasedaround4.36%, thelevelshifteddown6.2%,andthetrendlineincreased(x1.21)com- paredtoPhaseB.InPhaseD,Manny’smeanFTSpercentageperfor- manceimprovedby5.77%thelevelshifteddown21.1%,andthetrend linedecreased(÷ 1.00)comparedtoPhaseC.Overall,likeTom,Manny improvedinhisFTSpercentagemeanandcontinuedtoimprovephase byphase.Beforetheinterventionphase,hewasshooting64.72%,and aftertakingpartintheimagery interventionhisFTSpercentageim- provedto83.25%.

ImageryManipulationCheck.Toverifytheimageryexperience, participantsfilledoutamanipulationcheckform aftereach imagery session.Participantswereaskedtoratehowwelltheysaw,heard,felt, andhowwelltheyperformedtheimagerytheywereinstructedtodo ona4-pointLikertscalerangingfrom0(notatall)to4(verymuch).All fiveparticipantsreportedstrongtoverystrongimagerythattypically increasedfromPhaseAtoPhaseD.

Socialvalidationinterviewanalysis.Allparticipantsreportedthat theyfoundthePIinterventiontobeveryclearandwellstructured.PI helpedthemtoexperiencevividanddetailedimageryoftheFTSperfor- mancesituation,althoughitwaschallengingforsomeoftheminitially, astheyhadneverperformedimagerybefore.Forexample,oneofthe participantsmentioned“Ihaveneverdoneimagerybeforeanditfelt awkward”.Theyallmentionedusing alltheirsenseswhenpractising imagerytomaketheexperiencemorerealistic.Allparticipantsclaimed that,towardstheendoftheintervention,theyexperiencedsomeofthe feelingsthattheywouldgetwhenactuallyperformingFTS, buttoa lesserextent.

Imageryhelpedeachparticipantdifferently.Forexample,Scottre- portedthattheimageryhelpedhimwiththewayheapproachedthe FTSduringthegame,particularlyto“sortouthisroutine”.Henoticed thatduringimagerypracticeheconcentratedmoreonshooting,rather thantalkingtotheplayersandtherefereeasopposedtotherealgame situation.Tom,ontheotherhand,statedthatimageryhelpedhimnotto thinktoomuch.ForTom,imageryhelpedhimtoremove“allemotions andeverythingelse thatwasgoing on”.Hementionedthat thinking aboutphysicalaspectsofFTSduringPIhelpedhimtopaylessattention tohisnormalemotionalreactionsduringFTSperformance.Hestated,

“ItslowedtheFTpreparationdownandremovedtheemotionsandit madeitmoreinstinctive,whichisgood”.Hesuggestedthatthemore

hefocusedonthinkingaboutwhatheneededtodophysicallytoper- formFTSsuccessfully,thelessemotionwouldinterferewithhisperfor- mance.PItrainingalsogavehimthetimetoslowthingsdowninhis mind,whichheexplainedwaswhatheneeded.Withsupportfromthe PI,Jasonfeltverycalm,relaxed,andmoreconfidentonthefree-throw linethanhewasbeforetheintervention.“Thisisindirectcontrastto thesituationinthepastwhereIhavefeltrathernervousattheFTline, especiallyifIaminaperiodofbadformwhereIhaven’thitafewin awhile,andIgetextremelynervousinthosesituations”,hesaid.He statedthat“inonegame,evenafterImissedmyfirstFT,Icouldstay focusedandcalmandhitmysecondshotwithconfidence”,whichhe claimedhenormallycouldnotdopriortotheintervention.ForSam, creatingthepressuresituationinthefourthphasewasthehighlightof hisimageryexperience.Inhisopinion,byimaginingthathecouldmake shotswhenacrowdwaswatchinginthosehigh-pressuresituations,he felthecouldhitthoseshotswhenthepressurewasnotasintense.So, imageryhelpedhimtomanagepressurewhenhereallywasinthosesit- uations.Hepointedoutthathealwaysfailedtoignorepeoplewhowere watchinghim,andimagerytrainingtaughthimthatheshoulddealwith theaudiencepressureinsteadoftryingtoignorethepressure.Manny foundimagerytrainingreallyusefulbecauseithelpedhimtofocuson keyaspectsofFTSthatheneededtoperformattheFTline,andtoblock outalotofdistractions.Mannyreportedthathewasabletoconcentrate onhisshotsmore,ratherthanjustgettingtothelineandrushinghis shots,orlettingdistractingthoughtscomeintohismind.Specifically, PIhelpedMannytomanagehismind,whichmeantrejectingunneces- sarythoughtsthatcreatestress,suchas“whatifs”.Instead,hecould thinkaboutsomeotherusefulhints,likefocusingontherimandmak- ingthebasket.Headded,“Itisafamiliarscenewhenyougothrough yourroutine.Itislikeyouhavebeeninthosesituationsahundredtimes andyoufeelmorerelaxed”.Hefoundimageryveryhelpfulbysaying,

“Thepictureispaintedclearlyinyourmind,anditisgoodbecauseif youhavebeeninasituationlikethateveninyourmind,youcanget thosepointsinrealgamesaswell”.Overall,allfiveparticipantsfeltPI waseffectiveinpromotingtheirimprovement.Whiletwoparticipants reported thattheyfoundthechangesin deliveryatthestartofnew phasestobechallenginginitially,thisappearedtobebecausetheyhad nopriorexperienceofimagerywithinthecontextpresentedhere,and theysoonadjustedtothenewimagerycontent.Althoughtheimagery traininghelpedeachparticipantinadifferentway,theyallthoughtit playedacrucialroleinincreasingtheirFTSpercentage.

Discussion

Thepresentstudycannotbedirectlycomparedtopreviousresearch becausewearenotawareofanystudiesthathaveexaminedtheeffi- cacyofPIamonghighly-skilledsportsperformers,conductingtasksthat arewell-learned,inrealcompetition,overawholeleaguecompetition season.Williamsetal.(2013)conductedanimageryinterventionstudy, usingwhattheycalledlayered(LSRT)imagery.Thedifferencebetween thecurrentstudyandWilliamsetal.(2013)isthattheycomparedtwo conditions(layeredstimulusandresponsetrainingwithmotorimagery training)amongnoviceswhohadlowimageryability.Inthecurrent study, theparticipantswerehighly-skilledathleteswithmoderate to highlevelsofimageryability.Also,intheWilliamsetal.study,par- ticipantsweretheoneswhodecidedwhatpropositionstoaddtothe contentthattheyfeltwouldmaketheimageamorerealisticrepresen- tationoftheactualsituation,whereasinthepresentstudyparticipants weredirectedtogeneratespecificpropositionsbytheresearchers.Al- thoughmeaningfulimagerychosenbyparticipantshasbeenreported toresultinmoreeffectiveoutcomesinsomestudies(Lang,1979;Cum- ming & Williams,2013) itcould be debated. Forexample, whether self-selectedimagerywillbemoremeaningfulwoulddependonindi- viduals’priorexperiencewithimagery,aswellastheirskilllevel. In a previous studythat comparedself-selected andresearcher-selected imagerycontent,wefoundthatresearcher-selectedcontentproduced 111

slightlysuperioroutcomeswithparticipantswhohadlimitedpriorex- perienceof imagery(Kuanetal.,2017).Anotherstudyconductedby Quintonetal.(2014)examinedLSRTamongchildrenperformingsoc- cerskills.Inthisstudy,performancedidnotimprovesignificantlywith layering.However,MarshallandWright(2015)foundLSRTtobeef- fectiveinputtingperformance,whilenoimprovementwasshownina non-LSRTimageryconditionandacontrolcondition.

Fazeletal.(2022underreview)conductedafieldstudy,compar- ingaPIinterventiontoRI,RETI,andacontrolcondition.Participants wereskilledbasketballplayers.ThetaskwasFTSperformance,withfour phases,imageryoftheFTStaskaloneinthefirstphase,imageryofthe taskwithteammatesandopponentsroundthekeyinthesecondphase, inclusionofanaudienceinthethirdphase,andadditionofpressure, withashottowinthematch,inthefourthphase.Performanceimproved mostforPI,followedbyRI,whileRETIwaslittledifferenttotheControl condition.Thepresentstudywasdesignedtoexaminewhetherthesuc- cessofPIinafieldstudy,withhighly-skilledperformers,wouldtransfer torealcompetitionoveranextendedperiod,withsimilar,highly-skilled basketballplayers.ResultsofthisstudysupportourpredictionthatPI canbeeffectiveinthereal-worldcontextofseason-longcompetition,fo- cussedonperformanceofthekeyskillofFTS.Basketballplayers,teams, andtheircoachesarelikelytobemostimpressedbyFTSperformance.

Onaverage,thefiveplayersinthis studyimprovedtheirFTSfroma solid58.4%inPhaseAtoastrongFTSpercentageof77.4%inPhaseD.

Thepresentstudydoeshaveanumberoflimitations,someofwhich areinherentin SCD. Thesampleof fivebasketballplayers wasrela- tivelysmall,butitischallengingtoaskhighly-skilledplayers,perform- inginoneofthemostcompetitiveleaguesinthecountry,tocommittoa studyinwhichtheymustundertakeimagerytrainingforthewholesea- son.Also,publishedSCDstudiesinsportoftenhaveverysmallsamples (Barkeretal.,2013),includingasingleparticipant(Filgueiras,2016).

Certainlimitationsaremorespecifictothedesignofthisstudy.We hadnocontroloverthenumberoffreeshotsthateachplayerhadin eachmatch.Mostplayershadoneortwomatchesinwhichtheywere

“shutout” bystrongopposition,havingnofreeshotsinthatmatch(indi- catedbyNinFig.1).Arelatedlimitationisthatwehadnocontrolover variationsinthestrengthoftheoppositionindifferentmatches.This impactedonthenumberof FTSthat playershadin differentgames.

However,theoutcomemeasureweusedwaspercentageofsuccessful shots,whichtakessomeaccountofthosevariations.Alargernumberof shotsproducesmoreopportunitiestomiss,butonemiss,ifaplayerhas onlythreeshotsinamatch,resultsinalowerpercentage(67%success) thanmissingtwoshotsoutof10opportunities(80%success).Onone hand,playinginastrongteamwouldgiveaplayermoreFTSopportuni- tiesacrosstheseason.Ontheotherhand,theplayerscompetedagainst alltheotherteamsinthecompetition,whichaveragesoutthelevelof challengeacrosstheseason.

Inaddition,wehadnocontroloverthewayinwhichseveralex- traneousvariablesmighthaveaffectedperformanceofFTSindifferent matches.Thesevariablesincludewhetherthematchwasplayedathome oraway,theplayer’sperceptionoftheoppositionineachmatch,when (ontheclock)theFTSperformanceoccurred inthematch,whatthe matchscorewaswheneachFTSwasperformed,sizeandorientationof theaudience(proorcontheplayer’steam),andpressureexperiencedby theplayeratthetimeofeachshot.Infuture,moreextensiveSCDstudies couldmonitorsomeorallthesevariables.Atthesametime,theireffect couldbeexaminedmorepreciselyincontrolledfieldstudies,although thiswouldprobablyaffecttheecologicalvalidityofstudies.Thereis alwaysgoingtobeatrade-off betweendegreeofcontrolandecologi- calvalidity.Acombinationofcontrolledfieldstudiesandecologically validreal-worldstudiesmighthelptoclarifytheroleofvariablesthat aresystematicallymanipulatedinfieldstudiesandmonitoredasthey varynaturallyinSCDresearch.

Conductingresearchprojectsthatinvolveinterventionsoverawhole season,inleaguebasketballthatinvolves16to18weeksofcompetition, presentsproblems.Theparticipantsinthepresentstudywereallvolun-

teers,butunderthevaryingpressuresofhigh-levelcompetition,asthe seasonprogresses,evenvolunteersmightstarttoquestiontheircom- mitment.Playersdidnotpresentanymajordisruptions,whiletheirre- sponsestothesocialvalidationquestionnairedidnotsuggestanyprob- lemswithmotivation,butparticipantsmightnothavewantedtoraise anyconcernsabouttheireffortoncethestudywascompleted.Conduct- ingshortinterviewsperiodicallyduringalongstudylikethisonemight beaneffectivewayofmonitoringfluctuationsinparticipants’motiva- tion, mood,andotherrelevantpsychologicalvariables.Reflectionon FTS performance,perhaps,tells aninteresting story.Allfiveplayers werehighlyskilled.TheyhadsuccessfulFTSrecordsintheprevious season.Thus,improvingmighthavebeenachallengeduringtheseason westudied.Nonetheless,theyallincreasedtheirFTSperformanceby around20%fromPhaseAtoPhaseD,whichspeaksforitself.

Fortwoplayers,TomandSam,theseasonlastedlongerthanitdid fortheotherthree.Theywereinvolvedinfinals,whichprolongedthe seasonbytwomatches.Further,thesematchesinvolvedmorepressure becausetheywerefinals.Thesematchesoccurredattheendofthesea- son,whenplayershadjustbeeninvolvedinPhaseD,thehigh-pressure imageryphase.WedecidedtocontinuePhaseDintothefinals.Itispos- siblethatactuallyexperiencinghigh-pressurematches,immediatelyaf- terexperiencing,andwhilestillcontinuingtoexperience,high-pressure imagerymighthavedisruptedperformanceforthosetwoparticipants.

Inthesocialvalidationinterviews,oneplayer,whoparticipatedinfi- nals,reportedthatitwouldhavebeenhelpfultoexperiencethehigh- pressurephase ofimagerytrainingearlier,so thatitspositiveeffects weremoreestablishedbythetimethefinalsarrived.

Althoughresearchershaveexaminedtheeffectoflayeredandpro- gressive imageryon performance(Fazelet al.,2018; Quinton etal., 2014; Williams et al., 2013), as well as on psychological variables (Calmels etal., 2004a, b, Fazel etal., 2018; Williamset al., 2011), thenumberofstudiesthathavebeenpublishedislimited,whilenone haveemployedSCDs.Thus,thereisgreatpotentialforprogramsofre- searchexaminingthesepromisingmethodsofdeliveringimagerytrain- ing.Basicquestionsthatshouldbestraightforwardtoexaminerelate to whether PI effects can be generalized. For example, the present studyonlyincludedmalebasketballplayers.PIshouldbeexaminedin skilled femalebasketballers.Thestudyonlyexaminedoneskill,rais- ingthequestionofwhethersimilarresultswouldoccurwithotherdis- cretesportsskills,suchasgolfputting,soccerpenaltytaking,andpistol shooting.Thepresentsamplecomprisedmatureplayerswithagreat dealofexperience.StudiesshouldexaminewhetherPIbenefitsarealso evidentinyoungerathletes. Onestudyoflayeredimageryconducted withchildrenfoundno significantperformanceeffectin soccerskills (Quintonetal.,2014).Aproblemthatfrequentlyarisesinresearchex- aminingagedifferencesisthatvariationsinagecanbeconfoundedwith differencesinskilllevel,aswellasinevitablevariationsinexperienceof thetask.However,todate,therehavenotbeenanystudiesthathaveex- aminedagedifferencesofimagerytraininginthesametask.Thisraises anotherbasicissue,namelywhetherPIiseffectiveacrossawidevariety ofdiscretesportsskillsandbeyondtoserialtasks,suchasgymnastics floorroutinesandfigureskating, aswellasopenskills,thatis,skills performedinanunpredictableenvironment,suchasteamballgames andindividualracquetsports.Differentstudieshaveexaminedawide varietyofsportsskills,manystudieshavebeenlaboratory-based,others havebeenfieldstudies,andtherehavebeenasmallernumberofSCDs.

Studieshavevariedage,gender,skilllevel,andexperience.Thesevari- ationsmakeitdifficulttoidentifypatterns.ThestudyofPIisinitsearly stages,offeringtheopportunityforresearcherstodevelopprogramsthat controlasmanyofthesevariablesaspossible,whileexaminingtheef- fectsofonevariable.Forexample,whileexaminingtheeffectofPIon skilllevel,researchersshouldcontrolforageandexperience.Then,it wouldbepossibletocontrolskilllevel,whileexamininganotherkey variable,suchasexperienceofthetask.

Aproblemthathasimpactedonthestudyofimageryinsportisthe greatdiversityofcontextualandparticipantvariablesthathavebeenex-

F. Fazel, T. Morris, A.P. Watt et al. Asian Journal of Sport and Exercise Psychology 2 (2022) 106–113

aminedinresearchonimagery.Contextualvariables,suchasthenature ofthetask,canbeexaminedsystematicallyinfieldstudies,butthereis nosubstituteforresearchinrealmatchestostudytheeffectonPIof contextualvariables.Theseincludesizeandcommitmentofaudience, whichrelatestowhetherthematchisplayedathomeoraway,objec- tivequalityandperceivedqualityoftheopposition,perceivedpressure, andstateofthematchwhentheskillisperformed.Suchvariablescan bestudiedinSCDstudies,somebyrecordingmatchesonvideo,which canbeanalysedforoccurrenceofarangeofcontextualvariables,and othersbyconductingin-depthinterviews.Acombinationofanalysisof videosandinterviewscouldbemostrevealing.Forexample,videoanal- ysiscouldshowthattakingFTSinhigh-pressuresituationsinbasketball leadstosomeplayersproducingalowerpercentageofsuccess(choke), whereasothersincreasetheirpercentage(clutch),comparedwithFTS ingeneralplay.Interviewsmightsuggestthatthosewhochoketendto avoidhighpressure,whereasthosewhoclutchwelcomeandapproach thesamehigh-pressuresituations(Gröpel&Mesagno,2019;Hilletal., 2019;Maheretal.,2019,2020;Marchantetal.,2014).Importantly, thesecontextualvariablesarealsofactorsthatshouldbeexaminedfor effectivenessaspartofPItrainingprograms,bothindividuallyandthen incombination.Inthestudyofcontextualvariablesasfactorsthatinflu- encebehaviourduringtheimplementationofPIprogramstoenhance sportsperformance,andtheexaminationofPItrainingprogramsthat aimtohelpathletes copewiththepressure presentedby contextual variables,amore fine-grainedanalysisof athletes’experiencescould begleanedbyconductinginterviewsattheendofeachphase,notjust attheendofthewholeprogram.

Conclusion

BecausethepresentstudyisoneofthefirsttoapplythePIdelivery methodinareal-world,high-levelcompetitioncontext,moreevidence isrequired,examiningPIundersuchconditions.Nevertheless,somein- sightscanbetakenfromtheoutcomesofthisresearch.Followingupon itseffectiveness,comparedtoRI,RETI,andacontrolconditionina4- phasefieldstudy,thepresentstudysupportstheeffectivenessofPIwith highly-skilled,malesportsperformersincompetitionoverawholebas- ketballseason.Reflectingonthedifferencesbetweenthepatternsofper- formanceacrossphasesofparticipantsinthisstudy,itappearstobeim- portanttounderstandthecontextofperformance,aswellascharacter- isticsofindividualplayers.Conclusionsshouldbedrawnwithcaution, butbasedonperformancevariations,aswellascommentsmadeinthe socialvalidationquestionnaire,introductionofahigh-pressurePIphase closetothestressfulendoftheseasondidhavedifferenteffectsonvar- iousplayers.Oneortwoplayersfelttheirperformancewasdisruptedin PhaseD,whereasotherscontinuedtoimprove.Thiswasalsoinfluenced bythecontinuationofPhaseDduringfinalsfortwoplayers.Although improvementsforallfiveplayersfromthebaselinePhase AtoPhase D,thefinalphase,support theuseof PIwith highly-skilledplayers, whoseperformancemightnototherwiseshowsystematicperformance increasesacrossaseason,careshouldbetakeninthedesignofPIstud- ies,bothintermsofthespecificcontentofimagery,andinitstiming.

PractitionerswillbeabletodesignindividualisedPItrainingprograms, oncefurtherevidenceemergesfromstudiesthatcontrolormonitorkey contextualandpersonalcharacteristics.Thereisnodoubtthatthereis muchtobelearnedfromwell-designedstudiesoffactorsinfluencingthe impactofPI,particularlySCDstudiesinreal,competitivesport.

Conflictofinterest None.

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