KINE4060IndependentStudyEye­HandCoordinationinEliteAthletes:

RelationshipofEye­HandCoordinationandPhysicalFitnessTestResultsandNHLPlayingPotentialinElite­LevelIce

HockeyPlayers

EricaRobinson#208227423May18,2009Prof.LaurenSergioKINE4060

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RelationshipofEye­HandCoordinationandPhysicalFitnessTestResultsandNHLPlayingPotentialinElite­LevelIceHockeyPlayersByEricaL.RobinsonAbstract TheprimarypurposeofthisstudywastodeterminewhichfitnessandmotorcontrolvariableshavethehighestcapabilityforpredictinghockeyplayingpotentialattheelitelevelasdeterminedbyyearstakentogettotheNHL(yNHL).Thesecondarypurposesofthisstudyweretocompareifthesevariablesweresimilartopreviousvariablesfoundtopredictsuccessintermsofdraftselectionorder,andtodevelopandtestapredictivemodelforyearofentryintotheNHLpost‐NHLEDCombineTesting.Fitnesstestresultsandmotorcontrol(eye‐handcoordination)testresultsweregatheredfromtheNHLEDTestingCombinefromyears2005‐2007andcomparedwithyearstakentoattainNHLstatusonatotalof276players.Regressionmodelsrevealedbimanualtimefromtheeye‐handcoordinationtasktohavepredictivevalueinallpositionsexceptgoalies,forwhomtotaltime(bimanual+slalom)waspredictive.TheonlysimilarvariablefoundinpreviousstudiesthatdeterminedsuccessattheelitelevelasdeterminedbydraftselectionorderandfoundinthisstudytodeterminesuccessintermsofyNHLwaslongjumpfortheskatingpositions(forwardsanddefense).Thepredictivemodelwasdevelopedandtestedondatagatheredfromthe2008NHLEDTestingCombineandfoundpredictedyNHLtohavelowcorrelationwithactualyNHL.ThisshouldbeupdatedinfollowingyearssincegenerallymoreplayersmakeittotheNHLinyears2and3aftertestingandonlyoneyearhassinceelapsedforplayerstestedin2008.Inconclusion,eye‐handcoordinationscoreshavepredictivevalueindetermininghowlongitwilltakeaplayertoattainNHLstatus.Introduction Icehockeyisaphysicallydemandingcontactsportthatreliesonbothanaerobicandaerobicenergyproductionsystems,withshiftslastingfrom30–80seconds(Quinneyetal2008;Burretal2008).Thesehigh‐intensityskatingboutsrequirerapidacceleration,changesinvelocity,andtheexecutionofamultitudeofskilledmaneuvers(Quinneyetal.,2008).WhilepreviousstudieshaveexaminedtherelationshipofphysicalfitnesstestresultsderivedfromtheNationalHockeyLeagueEntryDraft(NHLED)Combineeachyearwithhockeyplayingpotential,therearetodatenostudiesexaminingthepredictiveimpactofmotorcontrolscoresinhockeysuchaseye‐handcoordination.Whilethecurrentmethodoftestingeye‐handcoordinationisafairlyrecentinclusionintheCombinetests,theimplicationsofthesescoresintermsofplayersuccessasmeasuredbyentryintotheNHLisofinterest. SeveralstudieshavepreviouslyexaminedwhichphysicalfitnesstestresultsdemonstratearelationshipwithhockeyplayingpotentialinplayersfromtheNHLEDCombineusingtheoutcomevariableofdraftselectionorder(Burretal2008;Buretal2007,Vescovietal2006).Thisoutcomevariablewasusedasameasureofsuccessin

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hockeybecauseitincludeson‐iceperformanceasassessedbycentralscoutingandthecombinationofphysicalfitnessvariablesderivedfromtheCombine(Burretal,2008).Theauthorsalsostateitisacknowledgedthatduringadraftateamwillalwayschoosethebestplayerstillavailableforselection,thereforeessentiallyrankingtheplayersonoverallplayingabilitywithineachyear’sdraft(Burretal,2008).VescovietalnotethatduringtheannualNHLdraft,eachteamhastheopportunitytoselectoneplayerperroundovertheeightrounds,andthemosthighlytoutedplayersaregenerallyselectedinearlierrounds(2006).Forthepurposesofthisstudy,YearofEntryintotheNHL(yNHL)wasusedastheoutcomevariableasthisisanobjectiveandmoreappropriatemeasureofsuccesswhichisofvaluetocentralscoutinganditwasspecificallydesirabletofindwhatrelationshipsexistbetweendatagatheredattheCombineandyearofentryintotheNHL.WhilethemajorityofplayersinvitedtoparticipateintheCombinetestingaredraftedattheNHLEntryDraft(NHLED)intheNHLdraftfollowingtesting,onlyroughly1/3oftheseplayersgoontotheNHL,andforthisreasonitisdesirabletounderstandwhichvariables,ifany,playaroleinthisdifferentiation. Thepurposesofthisstudyarefour‐fold:primarily,toseewhatimpactmotorcontrolscoreshaveonmakingitintotheNHL;toseewhichfactors(fitnessandmotorcontroltestingresults)predictaplayer’syearofentryintotheNHLandtowhatextent;toexamineifthepredictorvariablesforyearofentryintotheNHLareinlinewithpreviousfindingsofwhichpredictorvariablesarerelatedtodraftentryorder(Burretal2008,Vescovietal2006)andtodevelopandtestapredictivemodelbasedonthepredictorvariables,usingdatagatheredatthe2008NHLEDCombine.Methods AlldatawasobtainedfromtheNHLEDtestingcombineheldannuallyinMay/JuneduringwhichmembersoftheHumanPerformanceLaboratoryatYorkUniversitycarryoutalltestsandmeasures,allowingforahighdegreeofcontrolindatacollectionandreporting(Burretal,2008).Thetop110–120junioricehockeyplayersworldwideareinvitedtothetestingcombine,wheretheyparticipateinabatteryofoff‐icehockey‐relatedtestsdesignedtoassessplayerfitness(Burretal,2008)andmotorcontrol/eye‐handcoordination.Thedataforthisstudyoriginallyincludedyears2004to2008,however2004wasexcludedastheeye‐handcoordinationtestingprocedurewasstillbeingdeveloped.Datafrom2008wasnotusedinexaminingwhichpredictorvariablesarerelatedtoyearofNHLentry,butinsteadwasusedtotestthepredictivepowerofthemodel.Datafrom2005to2007wasusedtoexaminewhichvariablespredictedentryandfordevelopmentofthepredictivemodel. TestresultsfromtheHumanPerformanceLaboratorycollectedfromthephysicalfitnessmeasureswerecombinedwithdatagatheredfromtheSensorimotorNeuroscienceLaboratoryregardingeye‐handcoordinationscoresforanalysis.InformationondraftselectionorderandyearofentryintotheNHLfollowingCombinetestingwasobtainedfrombothwww.nhl.comandwww.hockeydb.com.EntryintotheNHLisdefinedashavingplayedatleastonegameintheNHL.Codingwasusedforposition,yearofentry,upperandlowerbodydevelopmentandrounddrafted.Rounddrafted/selectedwasreverse‐codedwith0beingneverdraftedand8beingdraftedinthefirstround;whileyearof

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entryintotheNHLwasbrokenupinto9categories:eachyearthataplayercouldpotentiallybecalleduptheNHLwasdividedinhalf,fromSeptembertoJanuarybeingthefirsthalf,andFebruarytoJunethesecond.Thisgaveapossiblescoreof1to8forthosewhomadeitintotheNHLwithinthefouryearsexamined,withallplayerswhodidnotmakeitinbeinggivenascoreof10.Fromthephysicalfitnessdataleanbodymasswasderivedbysubtractingbodyfat(lbs)from(total)weight(lbs).InfollowingwithBurretal,2008,abodyindexscorewascreatedbasedonanthropometricmeasuresincludingtheaboveleanbodymass(lbs),height(cm),andupperandlowerbodymusculardevelopment,bysummingthez‐scoresforeachmeasure.TestingProcedure TheNHLEDTestingCombinetakesplaceoveratwo‐dayperiodeachMayorJuneduringwhichhalftheplayersaretestedoneachday.Allparticipantsconformtostandardizedtestinginstructionsandnopracticetrialsareallowed.AlltestsandmeasuresarecarriedoutbyYorkUniversity’sHumanPerformanceLaboratory.ThetestsincludetheWingate30‐secondanaerobicpowertest(peakwattsandfatigueindex),aerobicpower(VO2max),physicaldevelopment,height,weight,percentbodyfatbasedonskinfoldthicknessatsixsites(chest,triceps,subscapular,suprailliac,abdomen,andthigh),gripstrength,benchpress,sit‐ups,push‐ups,standinglongjump,verticaljumplegpower,upper‐bodypower,flexibility,andisometricpushandpullforce.Fulldescriptionsaregivenintable1astakenfromBurretal2008.Bodyfatiscalculatedusingtheformula:PercentageFat=(sumofskinfoldsx0.0097)+3.64(Vescovietal,2006);Rightandleftgripstrengthwasfurthercombinedintoasinglescore.TheNHLEDtestingCombineisarrangedasacircuitinwhichplayersattempteachtestinadesignatedorderthatallowsforappropriaterecoverytimebetweentestsusingsimilarmusclegroups,andsothatcompletionofonetestdoesnotleadtoseveredecrementsinanother(Burretal,2008).Motorcontrol/eye‐handcoordinationscoreswereobtainedinaseparateareausingaPhantomRoboticInterfacedevelopedbyThomasMassieofSensAbleTechnologies.ThePhantomroboticarmisequippedwithembeddedtorquemotorsandisattachedtoahockeystickhandle.Playersmuststick‐handleaballthroughfourpylonsspacedanevendistanceapartonacomputerscreen.ThetorquemotorspushbackagainsttheplayerifthePhantomdetectschangingvelocityoriftheplayerisgettingtooclosetoanobstacle,thusmakingithardertonavigate(Hartley,2008).Scoresusedfromthistestingprocedureincludedominanthandslalomtimetocompletethetask,bimanualtime,andtotaltime(sumofslalomandbimanual).Assessmentofhandednesswasdoneviaawrittenquestionnaireoutlining11tasksandaskstheplayerwhichhandtheyusetocompletethemincludingwriting,throwing,holdingutensilsandwhichhandtheyholdloweronthehockeystick.Onlydominanthandslalomscoreswereused.

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Subjects Thestudysampleincluded276elitejunior‐levelhockeyplayersages17‐19,rankedasbeingamongthetop120playerseachyearworldwidebyNHLcentralscouting(Burretal,2008).Ofthese,159(57.6%)wereforwards,87(31.5%)weredefense,and30(10.9%)weregoalies.Afurthersub‐populationofskatingplayerswascreatedfromcombinedforwardsanddefenseasperBurretal2008,resultingin246(89%)skatingplayers.AnyplayerswhomissedmorethantwotestsattheCombinewereexcludedfromthesample,foratotalof46exclusions.ThosemissingtwotestsorfewerwereincludedandagainasperBurretal2008,themissingvaluewasreplacedwiththeoverallgroupmeanforthatspecificvariable. InaccordancewithYorkUniversitypolicy,thisinvestigationwasapprovedbytheofficeofhumanresearchethics,andwritteninformedconsentwasobtainedbytheparticipantsasdescribedbytheAmericanCollegeofSportsMedicine,andwiththeunderstandingthatparticipantnameswouldremainconfidential.StatisticalAnalyses AllstatisticalanalyseswereconductedusingMatlab7.4.0.Stepwiseregressionwasrunonallpositions,skatingplayers,forwards,defense,andgoalieswiththeoutcomevariableasyearuntilentryintotheNHL,aswellastheoutcomevariableofdraftorderselectiontodetermineifsimilarvariableshadpredictivevalueasseeninBurretal(2008).Stepwiseregressionwasusedtoidentifythesignificantpredictorvariables(P=<0.05)andR2foreachofthetenmodelswhichwereduplicatesofthesamefive–allpositions(n=276),skatingplayers(n=246),forwards(n=159),defense(n=87)andgoalies(n=30)–butthefirstfivehavingtheoutcomevariableofyNHL,andtheotherfivehavingtheoutcomevariableofdraftselectionorderforatotalof10models.Basedontheresultsofthestepwiseregression,aregressionequationwasformulatedutilizingthesignificantbetaweights.ThisequationwasusedtopredictyearofentryintotheNHL(yNHL)usingdatagatheredin2008,andthepredictionsweremeasuredagainsttheactualyearofentryusingsimplecorrelation.

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ResultsTable2:MultivariatemodelscomparingNationalHockeyLeagueEntryDraftpredictorvariablesandyearofentryintotheNHLasoutcome.

Model R R2(adjustedR2)

Predictors B(SE) Pvalue

One:Allpositions 0.298 0.089(0.076) ConstantVO2maxBimanualTimePush‐UpsMax#

15.406‐0.976‐0.1500.056

(p=0.0003)(p=0.0016)(p=0.0470)

Two:Skating 0.305 0.093(0.082) ConstantBimanualMax#PushUps

‐5.97620.1730.614

(p=0.000)(p=0.006)

Three:Forwards 0.297 0.088(0.071) ConstantBodyIndexBimanual

‐1.27950.1640.115

(p=0.0112)(p=0.0157)

Four:Defense 0.338 0.114(0.093) ConstantBimanualTime

‐3.30250.174

(p=0.0014)

Five:Goalies 0.858 0.737(0.671) ConstantEye‐HandTimeCombinedGripBenchpressPush‐UpsMax#BodyIndex

‐6.37760.1570.030‐0.268‐0.1490.536

(p=0.035)(p=0.011)(p=0.001)(p=0.014)(p=0.001)

Table3:MultivariatemodelscomparingNationalHockeyLeagueEntryDraftpredictorvariablesanddraft‐selection‐orderoutcome.

Model R R2(adjustedR2)

Predictors B(SE) Pvalue

One:Allpositions 0.152 0.023(0.016) ConstantPushUpsMax#

7.291‐0.061

(p=0.011)

Two:Skating 0.212 0.045(0.033) ConstantPushUpsMax#LongJump(in)

2.5976‐0.0680.050

(p=0.007)(p=0.023)

Three:Forwards*

Four:Defense 0.221 0.049(0.027) ConstantPushUpsMax#

8.3552‐0.105

(p=0.039)

Five:Goalies 0.420 0.177(0.118) ConstantPushUpsMax#

9.7008‐0.227

(p=0.021)

*Nosignificantpredictorvariablesderivedfromstepwiseregression

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Table4:PredictiveCapacityofRegressionFormulaforYearofNHLEntryUsing2008NHLEDData

Model Formula Correlationwith2008NHLEntryDataOne:Allpositions yNHL=15.406+(‐0.97553x

VO2max)+(‐0.15034xBimanualTime)+(0.056227xPushUpsMax#)

‐0.001

Two:Skating yNHL=‐5.9762+(0.17317xBimanualTime)+(0.61379xVO2max)

‐0.034

Three:Forwards yNHL=‐1.2795+(0.11519xBimanualTime)+(0.16398xBodyIndex)

0.022

Four:Defense yNHL=‐3.3025+(0.17369xBimanualTime)

0.034

Five:Goalies yNHL=‐6.3776+(‐0.14852xPushUpsMax#)+(0.53575xBodyIndex)+(‐0.26835xBenchPress#(lbs))+(0.030021xCombinedHandGrip)+(0.157xEye‐HandTime)

*Cannotderive(NaN)

Table5:ComparisonofPredictorVariablesonOutcomeVariablesforDraftSelectionOrderandyNHLModel: Burretal2008Draft

SelectionOrderPredictorVariables

CurrentStudyDraftSelectionOrderPredictorVariables

CurrentStudyyNHLPredictorVariables

AllPositions BodyIndexPeakWatts

PushUps(Max#)

PushUps(Max#)AbsoluteVO2maxBimanualTime

SkatingPositions BodyIndexPeakWattsFatigueIndexLongJump

PushUps(Max#)LongJump

AbsoluteVO2maxBimanualTime

Forwards BodyIndexPeakWatts

Nosignificantpredictors

BodyIndexBimanualTime

Defense BodyIndexPeakWattsFatigueIndex

PushUps(Max#) BimanualTime

Goalies N/A PushUps(Max#) PushUps(Max#)BodyIndexBenchPressHandGripEye‐HandTotalTime

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WithyNHLasthemainoutcomevariable,significantpredictorsforallpositionswerePushUps,AbsoluteVO2max,andBimanualTime.Forskatingpositionswhichincludedforwardsanddefense,significantpredictorvariableswereabsoluteVO2maxandbimanualtime.BimanualtimewasalsosignificantintheforwardsonlymodelalongwithbodyindexwhichwasalsofoundtobeapredictorvariablefordraftselectionorderbyBurretal(2008),andbimanualtimealonewasfoundtobeasignificantpredictorvariableforthedefensemodel.ThegoaliesmodelhadthehighestR2withroughly67%ofthevariabilitybeingaccountedforbythemodel,andhadthehighestnumberofsignificantpredictorvariablesincludingpushups,bodyindex,benchpress,andeye‐handtotaltime. Whencomparingmodelsusingdraftselectionorderastheoutcomevariable,pushups(max#)wasthesignificantpredictorinallmodelsbutforwards(whichdemonstratednosignificantpredictorvariable)andlongjumpintheskatingmodelwhichwasnotsubsequentlyseenineitherforwardsordefensealone.Thismaybeduetothelargersizeoftheskatingmodelbeingabletodetectsignificantpredictorvariables.InlinewithBurretal,thebestmodel(goalies)onlyaccountedfor11%ofthevariability. Whenmultipleregressionequationswerederivedusingthebetaweightsfromthesignificantpredictorvariablesasdeemedbythestepwiseregression,theywereusedtopredictyNHLfortheplayerstestedatthe2008NHLEDCombine.ThesepredictionsweremeasuredagainsttheactualyNHLusingsimplecorrelationtodetecthowwellthepredictivemodelfunctioned.Thecorrelationwithallmodelswaslow,andiscomplicatedbythefactthatmanyplayersarecurrentlylistedincategory10(nevermadeitintotheNHL)howevertheyhaveonlyhadtwoopportunitiesorpotentialentrypointsthusfarusingthecurrentstudy’scodingsystem(September–January=1,February–June2).OnlythetopfewplayerseachyearmakeitintotheNHLwithinthefirstyearandthelikelihoodincreasesinthecomingtwoyears,andthenproceedstodropbyyearfourfollowingtheNHLEDCombinetesting.Thereforethispredictivemodelmayprovetobemoreaccuratewhen2008playersarefollowedandrecordedforyNHLinthecomingtwotothreeyears.Discussion IncomparingresultsforpredictorvariablesfordraftselectionorderwithfindingsbyBurretal(seetable5),theonlysimilarityexistsbetweenskatingpositionsandthelongjumpvariable.IncomparingpredictorvariablesforBurretal’s(2008)draftselectionordervs.thecurrentstudy’syNHL,theonlysimilarityexistsforforwardsandbodyindex.Thismaysuggestfirstlythatbodyindexisofimportanceforforwardsintermsofoverallhockeysuccess,bothinbeingdraftedinanearlierroundandinmakingittotheNHL,butalsothatpredictorvariablesattainingtodraftselectionorderarenothighlyreflectiveofsuccessinhockeyasmeasuredbyattainmentofplayingintheNHL,whichisamoreaccuratemeasureofsuccessofincreasedvaluetocentralscouting.Thisisdemonstratedaswellbythefactthatwhile93.5%(258players)oftheentiresamplewasdrafted,only28.6%(79players)ofthetotalsampleeverplayedagameintheNHL.ThisoutcomevariableislikelystillsomewhatpredictiveofyNHLsincetheplayersthatdomakeittotheNHLtendtobeselectedintheearlierrounds,withthissampleinparticulardemonstrating72playersdraftedinthefirstround,62inthesecond,4inthe3rd,34inthe4thround,and18orlessineachofrounds5–8.

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IncomparingresultstothosefoundbyVescovietal(2006),whofoundtheretobenopredictorvariablesintermsofdraftselectionorderastheoutcomevariable,theresultsofthisstudycontrastthatasnotedbyPushUpsbeingasignificantpredictorvariableamongstmostmodels.Vescovietalalsonotethatusingdraftselectionorderasanoutcomevariablemaybelimiting,sothisstudyfeaturesanalternativeoutcomevariable(yNHL)asastrength. Ofparticularinterestistheroleplayedbyeye‐handcoordinationscoresaspredictorvariablesinyNHL.Bimanualtimewasasignificantpredictorinallmodelsexceptgoalies,inwhichtotaltimewasasignificantpredictorvariable,whichdemonstratesthateye‐handcoordinationscoreswereofsignificantimportanceforallfivemodels.Thisshineslightontheimportanceofthenewereye‐handcoordinationtestinganditspossiblepredictivevalueintermsofyearsittakestogetintotheNHL.Italsogivescredittotheimportanceofoff‐icetestingwhichisincontrastwithconclusionsbyVescovietal(2006). Limitationsofthecurrentstudyincludethesmallersamplesizewhichisnearly¼thatofBurretal(2008)andmaybethereasonwhymorepredictorvariablesweredetectedbythoseauthorsfortheoutcomevariableofdraftselectionorder.WhilethegoaliesmodelhadthehighestR2,itwasafairlysmallsubpopulationofonly30players.Alsotheskatingplayerssubpopulationaswellasforwardsanddefensesubpopulationsmayhavebeentoosmalltodetectadditionalpredictorvariables.Furtherresearchusinglargersamplesizesisneeded.Otherlimitationsincludenotbeingabletousedataearlierthan2005duetolackoforimpropertestingofeye‐handcoordination,leadingtoalimitedsamplesize.Alsooflimitationisthatthepredictivemodelusingdatafrom2008onlyallowsfortwopossibletimepointsofentryintotheNHLalthoughthepredictivemodelgoesbeyondthisfirstyear,somoredatawillhavetobecollectedinthefuturetotestthepredictivecapacityofthemodel. ThestrengthsofthisstudyincludeusingyNHLastheoutcomevariablewhichhasyettobestudied,aswellasthedevelopmentofapredictivemodel/equationthatmaybeusedinthefuture.Itisimportanttonote,however,thatthemajorityofthemodelsaccountedfor7–9%ofthevariability,withgoaliespresentingthehighestR2accountingfor67%ofthevariability.ThisentailsthatwhilephysiologicalandmotorcontrolscoreshavesomeimportanceinpredictingdraftselectionorderoryNHL,therearealargenumberofextraneousfactorsincludingpastperformance,gameobservation,playeraggressiveness,psychologicalfactors,andprofessionalscoutingintuition(Burretal.,2008).Whilephysiologicalandmotorcontrolscoresdonotrepresentalargepercentageofthevariation,theycanserveasusefulbenchmarkmeasurementstotrackplayerprogressanddevelopmentduringtheseasonandtheircareer.Acknowledgments Thisprojectdidnotreceiveanyrewards,monetaryorotherwise,fromexternalcompaniesorequipmentmanufacturers,withtheexceptionofYorkUniversity’sworkingcontractwiththeNHLforthepurposesofthecentralscoutingcombinefitnesstesting.IwouldliketoacknowledgeRoniJamnikforprovidingthephysiologicaldataandLaurenSergioforthemotorcontroldataaswellassinceregratitudeforherguidanceincompletingthisstudy.

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References Burr, J.K., Jamnik, R.K., Baker, J., Macpherson, A., Gledhill, N., McGuire, E.J. (2008). Relationship of physical fitness test results and hockey playing potential in elite-level ice hockey players. Journal Of Strength and Conditioning Research. 22(5):1535-1543. Burr, J.F., Jamnik, V.K., Dogra, S., Gledhill, N. (2007). Evaluation of jump protocols to assess leg power and predict hockey playing potential. Journal of Strength and Conditioning Research. 21(4):1139-1145 Green, M.R., Pivarnik, J.M., Carrier, Womack, C.J. (2006). Relationship between physiological profile and on-ice performance of a national collegiate athletic association division I hockey team. Journal of Strength and Conditioning Research. 20(1) 43-46. Hartley, M. (2008, September 22). Prospects keep hand on the stick, eye on the screen. Globe and Mail Quinney, H.A., Dewart, R., Game, A., Snydmiller, G., Warburton, D., Bell, G. (2008). A 26 year physiological description of a national hockey league team. Appl. Physiol. Nutr. Metab. 33: 753-760 Vescovi, J.D., Murray, T.M., Fiala, K.A., VanHeest, J.L. (2006). Off-ice performance and draft status of elite ice hockey players. International Journal of Sports Physiology and Performance. 1:207-221.