ASYMMETRY OF PADDLING TECHNIQUE, ITS SELECTED CONDITIONS AND CHANGEABILITY IN HIGHLY ADVANCED KAYAKERS

Abstract

Available literature lacks reports examining the asymmetry of kayak paddling technique and particularly its determinants as well as the variability in relation to the sport level and gender of the athlete.
Consequently, this study aimed to reveal: 1) changes in the asymmetry of the paddling technique resulting from athlete’s gender and the distance covered; 2) relationships between the degree of the asymmetry of the paddling technique and the sport level of athletes; 3) relationships between the paddling technique in a real kayak and the asymmetry of muscle mass distribution; 4) relationships between the asymmetry of the paddling technique performed on kayak ergometer and muscle mass distribution; 5) relationships between the paddling technique in a real kayak and the asymmetry of spinal segment mobility; 6) relationships between the asymmetry of paddling technique performed on kayak ergometer and the asymmetry of spinal segment mobility; 7) relationships between the asymmetry of muscle mass distribution and the asymmetry of spinal segment mobility; and 8) the levels of the asymmetry of the paddling technique resulting from athlete’s gender.
This study included 65 highly-experienced female and male kayakers, most of them members of class I or master class and possessing long professional experience, among them junior and senior representatives of Poland. A kayak and a kayak ergometer were used to determine the parameters of paddling technique. Mobility of cervical, thoracic and lumbar spine, in three planes, was determined based on electrogoniometric method. Additionally, body composition was analyzed with an aid of electric impedance. This study has revealed that female kayakers representing lower sport levels are characterized by higher asymmetry of paddling technique. However, this hypothesis was confirmed by kayak ergometer tests only.
Sport training of kayakers should be oriented towards increasing the muscular symmetry of lower limbs as this parameter is associated with better paddling technique. Also, cervical spine mobility in sagittal plane should be controlled since its lower values can affect sport results negatively.
In the case of female kayakers, higher asymmetry of cervical and thoracic spine mobility in coronal plane was reflected by an improved paddling technique. However, potential harmful health consequences of an increased asymmetry in coronal plane, namely the risk of developing lateral scoliosis, should be excluded.
Sport training resulted in a greater spinal rigidity and a lesser mobility of spinal segments, particularly in sagittal plane. This was reflected by a higher stability of the body, and favored more regular paddling, particularly more favorable bilateral recovery to propulsion time ratios.
Plausibly, proper utilization of body rotation during paddling by athletes characterized by higher muscle mass asymmetry required compensation by higher symmetry of lumbar spine rotation. In senior kayakers, the asymmetry was lower in females than in males since the former has more time for paddle rotation due to lower frequency of paddling.

Full text

EUGENIUSZ PIASECKI UNIVERSITY SCHOOL OF PHYSICAL EDUCATION
IN POZNAŃ
INTERNATIONAL ASSOCIATION OF SPORT KINETICS (IASK)
IASK LIBRARY – Vol. 35
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Mateusz Rynkiewicz, Włodzimierz Starosta
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ASYMMETRY OF PADDLING TECHNIQUE,
ITS SELECTED CONDITIONS
AND CHANGEABILITY
IN HIGHLY ADVANCED KAYAKERS
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POZNAŃ – WARSAW 2011

Sponsorofmonograph:thePolishMinistryofScienceandHigherEducationinthe
implementationofthepromotergrantfordoctordegreeNo.N404515738

Reviewers:Prof.Dr.hab.JózefDrabik
(UniversitySchoolofPhysicalEducationandSportinGdańsk)
Prof.Dr.hab.MarekZatoń
(UniversitySchoolofPhysicalEducationinWrocław)
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Projectofcover: BartłomiejZwoliński,KrzysztofZwoliński
Figures: MateuszRynkiewicz,EmilianDuda,WłodzimierzStarosta
Photos: MateuszRynkiewicz
TechnicalEditor: GrzegorzChmielewski
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Breaking: GrzegorzChmielewski
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Contents
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1.   Preface(W.Starosta)............................................................................................ 7
2. Literaturereview................................................................................................ 13
2.1.Humanmovementsinviewofsymmetryandasymmetry........................... 13
2.2.Kayakinginscientificstudies....................................................................... 22
2.2.1.Shortdescriptionofthediscipline..................................................... 22
2.2.2.Conditionandcoordinationmotorabilitiesrequiredinkayaking...... 24
2.2.3.Paddlingtechnique............................................................................ 30
2.2.4.Otherstudiesperformedinkayakers................................................ 32
2.3.Determinantsofmuscularstrength............................................................. 33
2.4.Conclusionsfromliteraturereview.............................................................. 34
2.5.Reasonforthisstudy................................................................................... 35
3. Objectivesandhypotheses................................................................................ 37
4. Material............................................................................................................. 39
5. Methods............................................................................................................ 43
5.1.Assessmentofspecificfitness...................................................................... 43
5.1.1.Determinationofpaddlingtechniqueinakayak............................... 43
5.1.2.Determinationofpaddlingtechniqueonkayakergometer............... 44
5.1.3.Racingspeed...................................................................................... 47
5.2.Analysisofbodycompositionandmusclemassdistribution....................... 47
5.3.Mobilityofspinalsegments.......................................................................... 49
5.4.Statisticalcalculations.................................................................................. 50
6. Results................................................................................................................ 53
6.1.Asymmetryofpaddlingtechniquedependingonthedistancecovered
byfemaleandmalekayakers..................................................................... 53
6.2.Sportlevelsandpaddlingtechniqueasymmetry......................................... 59
6.3.Asymmetryofmusclemassdistributionandpaddlingtechnique............... 65
6.4.Asymmetryofmusclemassdistributionandtheasymmetryofpaddling
techniqueonkayakergometer.................................................................. 69
6.5.Asymmetryofspinalsegmentmobilitywithregardstopaddlingtechnique
characteristics............................................................................................ 70
6.6.Asymmetryofspinalsegmentmobilityandtheasymmetryofpaddling
technique................................................................................................... 80
6.7.Asymmetryofmusclemassdistributionandasymmetryinspinalsegment
mobility...................................................................................................... 89
6.8.Relationshipbetweentheasymmetryofpaddlingtechnique
andthegender........................................................................................... 92
7. Discussion.......................................................................................................... 99
7.1.Asymmetryinpaddlingtechniquedependingonthedistancecovered
byfemaleandmalekayakers..................................................................... 99

–4–
7.2.Sportlevelsandpaddlingtechniqueasymmetry....................................... 101
7.3.Asymmetryofmusclemassdistributionandpaddlingtechnique............. 104
7.4.Asymmetryofthemusclemassdistributionandtheasymmetry
ofpaddlingtechnique.............................................................................. 106
7.5.Asymmetryofspinalsegmentmobilitywithregardstothepaddling
techniquecharacteristics......................................................................... 107
7.6.Asymmetryofspinalsegmentmobilityandtheasymmetryofpaddling
technique................................................................................................. 111
7.7.Asymmetryofmusclemassdistributionandtheasymmetryofspinal
segmentmobility..................................................................................... 116
7.8.Relationshipbetweentheasymmetryofpaddlingtechnique
andthegender......................................................................................... 117
8. Conclusions...................................................................................................... 119
9. References........................................................................................................ 121

ShortinformationaboutIASKanditsspeciallibrary............................................... 143
Indexofauthors...................................................................................................... 147


–5–
List of abbreviations used in the work 
Lp.AbbreviationsExplanation
1AmaxAsymmetryofmaximalaccelerationofkayak[%]
2AminAsymmetryofminimalaccelerationofkayak[%]
3AampAsymmetryofkayakaccelerationamplitude[%]
4AcAsymmetryofintegralofagraphofkayakacceleration
changes[%]
5AtmaxAsymmetryoftimetomaximalacceleration[%]
6%water40sAsymmetryoftherecoverytopropulsiontimeratioduring
asinglecycleofpaddling[%]
7ABAsymmetryofmusclemassdistributionbetweenrightand
leftsideofthebody[%]
8AAAsymmetryofmusclemassdistributioninupperlimbs[%]
9ALAsymmetryofmusclemassdistributioninlowerlimbs[%]
10ACZGPTAsymmetryofthecervicalspineflexioninthesagittal
plane[%]
11ACZGBAsymmetryofthecervicalspineflexioninthetransverse
plane[%]
12ACRAsymmetryinthecervicalspinerotationinthecoronal
plane[%]
13AThZGPTAsymmetryofthethoracicspineflexioninthesagittal
plane[%]
14AThZGBAsymmetryofthethoracicspineflexioninthecoronal
plane[%]
15AThRAsymmetryofthethoracicspineflexioninthetransverse
plane[%]
16ALZGPTAsymmetryofthelumbarspineflexioninthesagittal
plane[%]
17ALZBAsymmetryofthelumbarspineflexioninthecoronal
plane[%]
18ALRAsymmetryofthelumbarspinerotationinthetransverse
plane[%]

–7–
"UndertheinfluenceofPythagoreans,
andinaccordancewiththeirtheory
TheGreeksstartedtocallbeautysymmetry,
orproportionality.
Ratio‐istheobjectivebasisofallbeauty."
(Tatarkiewicz,2006)





1. Preface

Symmetryisaharmoniousstructureofthebody,meaningitsproportions,
andbalancebetweentwoelementsofaparticularwhole.Theinseparable
linkbetweenbeautyandsymmetryhasbeenemphasizedforalongtime.
Thereisalsoanotherdefinitionofthisconceptthatpertainstobilateralsym‐
metry,i.e.thesymmetrybetweenrightandleft.Theseconceptsapplynot
onlytothebodystructure(morphologicalsymmetry),butalsototheexecu‐
tionofmovements(functionalsymmetry).Asymmetryisaconceptthatisop‐
positetosymmetry.Theseconceptsarecloselyrelatedandcomplementary;
thisisparticularlyevidentinthemovements,wheretheirvariabilitymayoc‐
cur.Thismeansthattheasymmetricmovements,underconsciousinfluence
andcontrolofthepractitioner,maybecomesymmetrical.Thephenomenon
ofmorphologicalasymmetryhasbeenthesubjectofresearchofnumerous
authors,functionalasymmetryhasattractedmuchlessattention,andonlya
fewillustratedtheirinterdependence.
Human’sexternalappearanceindicatesratherasymmetricalarrange‐
mentofthebody’sstructure,butitsfunctionaldiversityissignificant,be‐
causemostpeoplearerighthanded,whichimposestheneedtoadapttothe
leadingelementoftheiractivities.Classifyingpeopleinregardstothisspecific
featureoftheirdevelopmentisoftenmarginalized.Inthescienceofhuman
movement‐anthropokinesiologytheclassificationsystemthattakesintoac‐
counttheeffectofmotorfunction,includingsportdisciplines,onthehuman
bodyispoorlypublicized.Theclassificationsystembasedonthedifferences
inthemovementsbetweenthetwosidesistakenintoaccounttoasmallex‐
tent.Yet,theimpactofexercisesonthebodyofthepractitionerdependson
thedifferencesinthemovementsbetweenthetwosides.

–8–
Itiswidelyacceptedthatsymmetricalexerciseshaveabeneficialeffect
onthehumanmovementapparatus(Woodworth,1903;Starosta,1975).
First‐of‐all,thisisduetothecomprehensiveeffectsonthecentralnervous
system.Secondly,asaresultoftheinvolvementofthenon‐dominant
hemisphereofthebrain.Consequently,theabilitytoperformmorecomplex
exercisesimprovesduetotheimprovementinthefunctioningofthecentral
nervoussystem.Boththesymmetricalandasymmetricalexercisesmodify
humanmovementapparatus,forcingitsadaptationtothespecificexercise.
Thisisparticularlyevidentinprofessionalsport,inwhichexercisesare
executedforanexceptionallylongperiodoftime,andthenumberofthe
repetitionsoftheperformedexercisesreachesmanythousands.
Theequalizationofthepreparationlevel,includingtechnicalpreparation,
hasbeenobservedwithincreasingfrequencyinmodernsport.This
intensifiesthecompetitionandincreasesthedifficultyintermsofachieving
asignificantsportresult.Itistheresultofincreasedunderstandingofthe
functioningofthehumanbody,thepropagationofthegeneralprinciplesof
training,butalsoamoresuccessfulselectionofcandidatesforthevarious
sportdisciplines.
Thephenomenonofsportsinjuries,whichhasbeenobservedtooccur
withincreasingfrequencyandeliminatesathletesfromparticipationin
sportstemporarilyorpermanently,istakingplaceatthesametimeasthis
enormousprogress.Theyarecausedmostlybyvariouskindsofloadvaria‐
tionsthatoccurmorefrequentlyindisciplinesinwhichtheprimary(working)
exercisesrequireasymmetryofmovement.Suchadversechangesarein‐
creasinglyfrequent.First‐of‐all,becauseasymmetryofmovementdominates
inmostdisciplines,eveninthosewherethereisapparentsymmetry.Sec‐
ondly,inthosefewclearlyasymmetricdisciplines,preventativeexercisesare
usedinordertocounteracttheformationoftheasymmetry.Unfortunately,
sofar,intheory,aswellasinsportstrainingpracticethelongsincedevel‐
opedclassificationsystemthatdividessportsdisciplinesinto:symmetric,
asymmetricandmixedhasnotbeenpublicized(Starosta,1975,1990,2008).
Theindirecteffectoftheexistingstateofaffairsistheequaltreatmentofall
disciplinesandabandonmentofexercisesdesignedtopreventtheeffectsof
unilateraltrainingloads.
Itisanextremelyimportant,butoverlookedproblemofmodernsport,
particularlyinthedisciplinesinwhichasymmetrydominatesinthebasic
movements,suchaspaddlingincanoeingorinrowing(longoars),fencing,
trackandfieldjumpsandthrows.Thisproblemrequiressystemicsolutions
toprotectsportsmenfrominjury,andthustoenablethemtoachieve

–9–
increasinglybetterresultsandamuchlongercareer.Againstthebackground
oftheseconsiderations,theexceedinglyaccurateandlaconicthoughtofa
greatsculptor,painter,architect,andartist,MichelangeloBounarroti[1475‐
1564]remainscurrentandinstructive:"Donotunderestimatethelittle
thingsbecauseperfectiondependsonlittlethings,andperfectionisnolittle
thing."Aimingforexcellencehasalwaysstimulatedthesearchfornewsolu‐
tions,andultimatelyledtodiscoveries,aswellastorecoveringreserves.
Amongthem,careforthesymmetryofthemovementsdeservesspecial
attention.
Symmetryofmovementisahard‐to‐attainperfection.It'seasierto
achieveitinsportswithcyclicmovements,forexamplecanoeing,thanin
acyclicones.Intheformersports,itispossibletoconductanongoinganaly‐
sisofmovements,comparetheirqualityandmakeimmediatecorrections.
Hence,amuchwiderrangeofthesymmetryoftechniqueisobservedinthem
anditpertainsespeciallytoleft‐handedindividuals,inwhomtheprocessof
balancingtheefficiencyofbothsidesofthebodyiscarriedoutfromearly
childhoodtooldage.Theviewthat:"Theleft‐handedindividualalwayshasa
certainadvantageovertheright‐handedindividual,becausetheright‐handed
individualnevertrainedintheuseofhislefthandasmuchastheleft‐handed
intheuseoftherightone.”islegitimate(Boehmig,1973,137).
Thecontentofthismonographpertainstotheasymmetryofpaddlingin
kayaking.Theherebypresentedresultsofthestudiesconductedon65high‐
classmaleandfemalekayakershaveshownthatevenseeminglysymmetri‐
calkayakpaddlingaffectstheindividualsegmentsofathlete’sspineinvari‐
ousways.Increasedasymmetryintherangeofmovementofthecervical
spinewasfoundtoimpairspeed,power,andperformedwork.Statistically
significantcorrelationsoccurredbetweentheasymmetryintherangeof
movementofspinesegmentsandasymmetryofpaddlingtechnique. This
maybedifficulttounderstandinlightofthehithertoprevailingbeliefthatthe
spineisaninseparablewhole.Perhapsbecauselittleknownweretheresults
oftheresearchconductedbytheteamofA.Krestownikow‐authorofthe
firsttextbook,"PhysiologyofSport"(1939)–andthestudentoftheNobel
laureate,I.Pavlov.Inthese,theexceptionalimportanceoftheheadposi‐
tion,hencethecervicalspineintheperformanceofvariousexerciseshas
beendemonstrated.Itwasknownlongagothatatoorapidraisingofthe
headafterthestartinasprintracecausestheliftingmovementofthebody,
whichreducesthespeedrateinthefinalstageoftherun.Thisrelationship
alsooccursduringmovementsthatrequireasignificanttwistingofthe
torsoinrelationtothepelvis,whichoccurswhenpaddlinginakayak.

–10–
Therefore,itishardlysurprisingthatthesemultipleturns/twistingofthe
torsoperformedwhilerowing,evenatshortdistancescausesignificant
displacementsinrelationtoeachindividualsectionsofthespine
Thepaddlingtechniqueinkayakingplaysadecisiveroleinachievingthe
ultimateresultduringthecompetition.Ofparticularimportanceisthe
precisionofmovementthatdependsonahighlevelof"feelingthewater"for
thewholedistance.Itallows“relaxed”paddling,meaningarationaluseof
themusclesandexceptionalcarefortheirskilfulrelaxationwhilepaddling
theentirelengthofthedistance.
Kayakpaddling,eveninchampion‐levelcompetitors,veryseldomisfully
symmetrical.Itisextremelydifficulttoachievesymmetryofthemovements
sincethevastmajorityofkayakershaveadominantupperlimb.Full
symmetryisseverelydisruptedbytheverylowstabilityofanarrowkayak.
Itiseasiertomanifestitinasinglepersonkayak,andmuchharderina
multi‐personkayak.Apartfrompreservingthesymmetryofthemovements
itisnecessarytomaintainthesamerhythmofpaddling.Manifestationof
thefullsymmetryofrowingisdisruptedbytheinstabilityofthenarrowkayak
whichiskeptstablebythemovementsofupperextremities,lower
extremitiesandtheentirebodyofthekayaker.Gradualreductionofthe
widthofkayakshascreatedmoreandmoredifficultconditionstomaintain
stability,whichisevenmorereducedundertheloadoftherower,especially
duringthecompetition.Thisisaspecificequilibriumwhichdoesnotoccurin
everydaylife,asregulatedinasittingposition,andthereforenotbymoving
thecenterofgravityinrelationtothestableground.Committingasmall
errorherecausesanimbalanceofthekayak,andalargeerrorcausesthe
overturningofthewholekayak.Theasymmetryinpaddling,formedbyyears
oftraining,alsoaffectsathlete'sspine,causingadversechangesthat
deepenwithincreasingexperience.Sofar,thesechangeshavenotbeen
recorded,notonlyduetothelackofproperequipment,butalsoasaresultof
lowawarenessoftheiroccurrenceandpossibleeffectsofpaddling
asymmetryinthis,seeminglyfullofsymmetry,discipline.
Thesignificantchangesthathavebeenrecordedinathletesthatwere
studiedbyuswiththehelpofspeciallyselectedmeasuringdevicesarea
significantnovelty,notonlyforkayaking.Theybegthequestion:howlarge
andadversecanthechangesinthespinebeinducedbyasymmetricalworking
movementsinotherdisciplines,i.e.paddlingononesideoftheboatina
kneelingpositioninacanoe?Themoresobecauseforthis,aswellasfor
manyotherasymmetricalsportdisciplines,effectivepreventiveor
correctivetotheemergingasymmetryofthebody,andespeciallyofthe

–11–
spine,leadingnottoorarelytochangesandoverloadcontusionsandeven
topermanentdisability,exercises,probablyhavenotbeendevelopedyet.
Suchataskshouldnotbeperformedbyanysportsdiscipline,muchlessone
thatispartoftheOlympicGames.
Theresultsofnumerousstudieshaveindicatedabeneficialeffectofthe
symmetricalmovementsonthehumanbody.Eveninthem,oftenina
disguisedform,asymmetryispresentbutmodifiedbythecompensatory
movements,forexampleinkayakingmakingthekayakmoveinastraightline
requiresfullsymmetryofpaddlingontherightandleftsides.Thisinvolves
usingtheequalforcebybothsidesofthebodyand“feelingthewater”with
bothbladesofthepaddle.Highlevelofusingequalstrengthand“feeling
thewater”isotherwiseknownastheabilityforkinaestheticdifferentiation
ofthesizeofthestrength.Thisabilityisshapedinathletesinthecourseof
manyyearsoftrainingandislargelygeneticallydetermined.Failureto
observethesymmetryofpaddlingresultsinitsdeviationfromthedirection
ofmovementandtheneedtousetheruddertodecreasekayak’sspeed.
Frequentuseoftherudderreducesthechanceofobtainingasignificant
resultduringthecompetition.Thismeansthatpaddlingneedstobecome
symmetricinordertomakerudderuseunnecessary.Theseexternal
manifestationsofpaddlingasymmetrycanbecompensatedindifferentways,
forexamplebyincreasedenergyexpenditure.However,theirnegativeimpact
canadverselyexternalizeintheformofchangesintheskeletalandmuscular
systemoftheathlete.Themostdangerousarethechangesinthespine,
whichwasestablishedforthefirsttimebythestudiespresentedinthis
monograph.Thisisoneofthekeyelementsestablishedduringthetests
carriedoutonkayakers,adisciplineplacedwithinthesymmetricsports
group.Exceptionalimaginationisnotneededinordertorealizehow
detrimentaltotheathletecanbeworkexercisesthatoccurinasymmetric
sportdisciplines.Especiallywhenthemanyyearsoftrainingarenot
accompaniedbysystematicallyperformedcorrectiveexercises.
Hence,thereasonforthegreatnumberofstraininjuriesofthelowerand
upperlimbscharacteristicforathletesspecializingintrackandfieldjumps
andthrows.Cantheybeavoided?Yes.Examplestakenfrompracticecertify
tothat.Amasterintheprevention(prophylaxis)ofstrainchangesintermsof
thejavelinthrowandtheformationofatypicalelbowinjurywasanexcellent
coach‐founderofthe"Polishjavelinschool”‐Z.Szelest.Asdemonstrated
byresearch(Starosta,1990,2008),athletestrainedbyhimneversuffered
typicaljavelininjuriesduringthemanyyearsoftraining.Theforemost
representativeofthisgroup,J.Sidło,obtainedresultsofover80mfor20

–12–
years.Inthisgrouptrained,amongothers,P.Bielczyk,W.Nikiciuk,Z.Radzi‐
wonowicz,U.Figwer,J.Kopyto,J.Głogowski,M.Machowina,W.Krupiński
andothers.
Littleknown"coachingtechniquesecret"ofZ.Szelestwasunprecedented
inanycountryproportionsoftheloadappliedtotheathlete’srightandleft
sidesofthebody,whoperformedonly25%ofthethrowswiththeleading
handandtherestwiththeother.Inthecourseoftrainingexercises,records
wereestablishedforeachhandthatindicatedsmalldifferencesbetween
them.Thisuniqueexampleofprovenlong‐termtrainingofhigh‐classathletes
canbeamodelfortrainersconductingtraininginotherasymmetricalsports.
Thegivenexamplesupportstheconceptofpreviouslyproposedmodelof
formationofmovementsthattakesintoconsiderationdifferencesinhuman
lateralization,aswellasthespecificsofdifferentsportdisciplines(Starosta,
1990,2008).Themodel,basedonextensiveresearchconductedonathletes
participatingindiversesports,foundthattheprocessofsymmetrisationmust
betreated:first‐of‐all,asanextremelyeffectivewayofpreventingthe
formationofthedifferentiationoflateralizationaffectinghumanbodyand
movements;secondly,asastilllittleusedmethodofimprovingsports
technique;thirdly,asanimportantmethodfordevelopingmovement
coordination.Theeffectivenessoftheprocessofsymmetrisationandits
extentdependslargelyontheathlete’slevelofcoordinationabilities.This
meansthattheprocessisfasterinhighlyskilledathletes.
Thevalueanduniquenessoftheresearchresultspresentedinthis
monographliesinthefactthatthenegativeeffectsoftheasymmetryof
movements,includingthoseinkayakpaddling,occureveninsymmetric
sports.Thisisawarningsignforthosepracticingother,seeminglysymmetric
disciplines,butespeciallythosethatareevidentlyasymmetric.Failuretouse
preventiveandcorrectiveexercisescanincreasethenumberofpeople
experiencingstraininjuries,orevenpermanentlyunabletoparticipatein
sports.Indeed,evenmodernprofessionalsportthatisfocusedonachieving
maximumresultsshouldnotinjuretheparticipants.
Warsaw,December10th,2011

Prof.Dr.hab.WłodzimierzStarosta
PresidentofInternationalAssociationofSportKinetics


–13–
"Fromtotallyunknownandsofarunexplainedreasons,
therighthandsignificantlydominatesoverthelefthand..."
(Bernstein,1991,179)




2. Literature review

2.1.Humanmovementsinviewofsymmetryandasymmetry
Symmetrydesignatesacommensuration,anditisoneofthebasic
structuralcharacteristicsofmostplantsandanimals(EncyclopediabyPWN,
2010).MostEumetazoaarecharacterizedbybilateralsymmetry,wherethe
longaxisofbodyservesastheaxisofsymmetry.Consequently,bothsidesof
abodyconstitutetwoidenticalmirrorhalves(Photo1).Inturn,asymmetry
correspondstoanydeviationfromsymmetry.Thereareseveralkindsof
asymmetry:morphological,functional,anddynamic.Amorphologicalasy‐
mmetrycorrespondstostructuraldifferencesofbodypartslocatedonboth
sidesofthecoronalplane.Afunctionalasymmetryreferstoafunctional
predominanceofoneofthefourlimbsoroneeye.Thisphenomenonisalso
frequentlyreferredtoaslateralization.Lateralizationcanbeunilateral,
characterizedbyafunctionalpredominanceofaunilaterallimbandeye,or
contralateral,forinstance,functionalpredominanceofrighthand,leftleg,
andlefteye.Finally,adynamicasymmetrypertainstobilateraldifferences
instrength,speed,ormovementstructure.
Humansarecharacterizedbyasymmetricalexternalstructure.However,
asymmetriescanbeobservedasearlyasduringfetallife(Jaśkowskiand
Kołaczkowski,1972;Stachura,1975;Wolański,1975).Althoughchildrenseem
symmetrical,thepredominanceofonelimboverthecontralateraloneis
alreadyobservedduringtheearlystagesoflife.Asymmetry,especiallythat
ofskeletalandmuscularstructures,canbemarkedlymodulatedbyexternal
factors(Charzewskietal.,1977;Koszczyc,1979;Ilnicka,1999;Omeyetal.
2000;Andreolietal.2001;Sanchis‐Moysietal.2004;Kazunorietal.2006).
Earlierstudiesofmorphologicalasymmetrydealtwiththemorphological
differencesoffeet(Bieniek,1967;Woitas‐Ślubowska,1976),shoulders
(EkiertandJachowicz,1962),andoftheupperandlowerlimbs(Starosta,
1969,1973,1983,1984,1985,1988,1990,2008;Jarosiński,1976;Koszczyc,
1989,1991).Furthermore,thedegreeofchangeinbodystructureresulting

–14–
fromasymmetricalsporttrainingwasstudied(Sidorowicz,1958;Kowaland
Zuchora,1962;Starosta,1975;PiechaczekandŁaska‐Mierzejewska,1977;
Tarociński,1977;PuniandStarosta,1979;Korbut,1980;Mekota,1984;
Hawrylaketal.,2001,2008;Sławińskaetal.,2006;Ciechanowskaand
Hagner,2007).However,literaturepertainingtothesymmetryand
asymmetryofprofessionalathletes,andparticularlytheevidenceofrotations
aroundvariousaxesofhumanbody,isrelativelysparse(Masiuta,1954;
Starosta1970,1971,1972,1973,1974,1975,1977,1978,1983,1984,1985,
1986,1988,1990,2008;Starosta,T.,Starosta,W.,1971;Dębczyńska‐Wróbel,
Starosta,2007).
Themovementsperformedbyathletespracticingvarioussportdiscipli‐
nescanbeclassifiedassymmetrical,asymmetrical,andcombined(Starosta,
1975,2008).Activitiesareconsideredsymmetricaliftheyareperformed
simultaneouslyonbothsidesofbody,asso‐calledmirrormovements,for
instancetheclassicandbutterflystrokesinswimming,andcontralateral
movements,alsoknownastranslationalmovements,suchasrunning,free‐
Photo1.„TheVitruvianman”,drawingcreatedbyLeonardodaVinci,
epictingidealproportionsofhumanbody

–15–
styleswimming,andcycling.Incontrast,movementsthatdifferdependingon
thebodysideareconsideredasymmetrical(Starosta,1975,1989,1991;
Koszczyc,1991).W.Starostaproposedthecomplexityscaleofcoordination
formovementsthatareperformedsymmetrically(Fig.1).Thefirstdegree
referstothelocalsymmetryofupperorlowerlimbs.Theseconddegree
pertainstoaglobalsymmetry,i.e.thesymmetryofentirebody.Thethird
degreereferstothesynchronizationofupperandlowerlimbmovements
withtherestofbody,forinstancesynchronizationofswimmingfreestyle
whilebreathingbothundertherightandleftarm,orkayakpaddling.Finally,
thefourthdegreepertainstothesynchronizationofentirebodymovements
withrightandleftrotations(Starosta,1975,28).
Itisestimatedthatapproximately96%ofthehumanpopulationis
characterizedbyapredominanceofoneupperlimboverthecontralateral
one(Starosta,1975,2008;Annet,1988).Incurrentsocieties,right‐handed
individualspredominateinthepopulationsofmostcountries(Drabik,1984;
Fig.1.Schematicpresentationofcomplexityscaleforsymmetrical
movements [Starosta,2005,2006,2008]

–16–
WolańskiandSiniarska,1986;Starosta,1990;Koszczyc,1991;Stokłosa,1998;
WieczorekandHradzki,2007).W.Starosta,however,findsthattheleft‐
‐handedpopulationcouldverywellbeunderestimatedintermsofimpor‐
tance,asmostreportspertainingtothisdataisvoidoftemporalandtarget
populationindicators(Starosta,2008,25).Reasonsthatcouldexplainsucha
grossunderestimationofapopulationportioncouldberelatedtochanging
socialconditions.Oneshouldkeepinmindthatleft‐handedpeoplewerejust
acceptedinsocietyatmostseveraldecadesago.Currently,westilllackthe
dataonthetruepredominantupperlimbintherepresentativesofsome
worldpopulations,forinstancethoselivinginAsia.Itshouldbenotedthat
Japanesecitizensareeducatedasambidextrous(Starosta,1975,1990).
Manyauthorspostulatethatthepredominanceofoneupperlimbcanbe
self‐perceivedbytheexaminee(Boulinguez,NougierandVelay,2001;
Boulinguez,VelayandNougier,2001).Additionally,thepredominantlimbcan
bedeterminedbyaskingasimplequestionaboutthepreferencesinutilizing
one’slimbduringperformingsimpleeverydayactivitiessuchaswriting,
painting,orteethbrushing(Oldfield,1971;Bryden,1977;Healeyetal.,1986;
Annet,1988;Sainburg,2002).
Performingcertainactivitieswiththepredominantarmwasprovedto
consumeslesstimeascomparedtocontralateralone(Flowers,1975;Todor
andDoane,1978;Annettetal.,1979;Carsonetal.,1992;Elliottetal.,1994;
BrydenandAllard,1998;Westwoodetal.,1998;Westwoodetal.,1999;
Brydenetal.,2000;BrydenandKay,2002).Furthermore,thesebilateral
differenceswereobservedtoincreasealongwithincreasingnumberofmove‐
mentsrequiredtoperformataskgiven(Carson,1992;Elliottetal.,1994;
Brydenetal.,2000).
Movementsperformedwiththepredominantarmarealsomarkedly
moreprecisethanthoseperformedwiththecontralaterallimb(Royand
Elliott,1989;Royetal.,1994,1999;Carsonetal.,1990;Elliottetal.,1995,
1999;Bryden,2002;Maruffetal.,1999;HeathandRoy,2000;Boulinguez,
Nougieretal.,2001;Boulinguez,Velayetal.,2001;BagesterioandSainburg,
2002;BrydenandKay,2002;Hausmannetal.,2004).Thisphenomenonis
postulatedtoresultfromdisruptionsinthecentralnervoussystemoccurring
duringtheformulationofinstructionsforagivenmovementtask(Annettet
al.,1979;Carsonetal.,1990,1992;Carson,1992;Carson,Elliottetal.,1993;
Carson).Thedisruptioncausesanecessitytospendmoretimetoinitiatethe
reversefeedbackneededfordirectcontrolofthemovementtaskperformed
bythenon‐dominantlimb(BarthelemyandBoulinguez,2002).Ahypothesis
alsoexistsregardingthelessefficientcoordinationofmusculartonebetween

–17–
theparticularmuscularsegmentsoftheleftarm(BagesteiroandSainburg,
2002,2003).Differencesinbiomechanicalstructurearepostulatedtoimpair
inter‐muscularcoordinationofthenon‐dominantlimb(Careyetal.,1996;
CareyandOttodeHaart,2001).
Thecourseofthelateralizationprocessoccurringinthebrainwasnot
entirelyunderstoodthusfar(Elliottetal.1995;Bryden,2002;Brydenand
Kay,2002).Accordingtoonetheory,theasymmetryofupperlimbsis
associatedwiththeasymmetryoftheregionscontrollingspeech,cognition,
andemotions(Annett,1988).Attheendofthe20th century,ahypothesis
emergedonlateralizationbeingtheresultofcooperationbetweenthe
dominantandnon‐dominantarmrequiredinperformingmanyeveryday
activities(Healeyetal.,1986).
Sainburg(2005)explainedasymmetryasaresultofthespecializationof
specificregionsoftherightandleftcerebralhemisphere.Accordingtothis
author,thepredominanthemisphereisequippedwithaspecializedcon‐
trollerofmovementtrajectory,determiningthemomentofforceandthe
movementamplitudeaccordinglytothescheduleoftheperformedmove‐
ment.Incontrast,thenon‐dominanthemispherehasaspecializedlocation
regulator,actinginareversefeedback.Thisregulatorismostlyresponsible
forcontrollingthemomentofforceandthetimeofitsexposure.In
Sainburg’s(2005)opinion,theasymmetryresultsfromstrivingtoreachhigh
coordinationlevelsinordertoimprovetheprecisionofmovementsper‐
formedbimanually,ratherthanfromthedevelopmentalasymmetryof
cerebralregionsthatcontrolspeech.Itisprobablethathumanslearned
precisemovementsofthearmmarkedlyearlierthantheydidspeech.These
aforementionedassumptionswereconfirmedbythestudiesofpatientswith
braininjuries(Haaland,2004),inwhommovementsrequiredalongertimeto
beperformedifthepredominantcerebralhemispherewasinjured,and
adecreasedprecisionofthemovementswasobserved