人間科学研究 Vol．20，Supplement（2007）
修士論文要旨
運動特性の違いによる伸張反射機能の特異的適応
Speci丘cAdaptationsofStret，ChRe且exFunctionsinIndividuals
WithDiffbrentAthleticBackground
小川 哲也（Tbtsuya Ogawa） 指導：鈴木 秀次
Introduction
DiSCuSSion
Human renex systemis known to undergo plastic
Fortheshort・latencycomponentofthestretchreflex，
adaptationsin response to physical activit，ies．More
from the result that there were no di飴rencesin the
importantly，theadaptationsaredependentonthetasks
galn，thedi飴renceinthestretchrenexamplitudecould
requiredfor the activities and are very speci丘C．The
not be attributed to the diffbrencein galn，but to
PreSentStudycompal・edthecharacteristicsoftheinput−
difEbrentlyappliedbiasessuchasthesubliminalfringe
output relationship or stretch reflex galn Within two
Or the presynapticinhibition．However，theinfluence
dif艶rent stretch renex pathways betweenindividuals
Of the subliminalfringe was omitted because of the
engagedinphysicalactivitiesrequlringdiffbrenttasks．
matched background activity between the groups
The neural mechanisms responsible for the renex
althoughthe possibility of the presynapticinhibition
responses were also investigated by applying
Stillremaineduncertain．Theotherpossibilitywasthe
COnditioningstimulusofvibratJion．
di飴rencein the muscle spindle susceptibilityin that，
Methods
alphaandgammamotoneuronsareco−aCtivated，butto
Subjects：12sprint一七rained
athletes
as
well
as12
a diffbrent extent．Since the vibration decreased the
endurance−trained distancerunnerS allbelonglng tO a
Short・1atencycomponentofthestretchre且exgaintoa
COl1egiateathleticteam．
Similarextentbetweenthegroups，WhereastheH−reflex
Experiments：Stretchreflexwasinducedinthesoleus
inthesprint・WaSfhrmoresensitive，itislikelythatthe
musclebyamechanicalperturbationattheankleJOint
di飴renceinthestretchrenexamplitudecouldprobably
dul・ing voluntary contraction of the muscle． The
beattributedeithertothedifEbrencesinthepresynaptic
StretChre皿exgaln，de丘nedastheslopeoftheregression
inhibition or the muscle spindle susceptibility since
linefor the relationship between the reflex response
H−reflexis reported to be more sensitive to the
amplitude against the angular velocity of the
presynapticinhibition thanin mechanically evoked
Perturbation，WaSeValuated．Influenceofthevibration
StretCh re且ex aIld muscle spindleis bypassedin
on stretch renex response as well as on H・reneX
H・renex．
responsewasalsoevaluated．
Summary
Result8
The present resultsindicated that there were no
There were no diffbrencesin the stret，Ch renex galn
di飴rencesintheinput−OutPutrelationshipbetweenthe
betweenthegroupsforbothshort−andmiddle・latency
SPrint−andtheendurance・grOuPSbothintheshort−and
COmPOnentS．Sprint−grOuP Showed relatively smaller
the middle−1atency components．The reflex amplitude
reflexamplitudetoaglVenStretChvelocit，yCOmParedto
wassmallerinthesprint，・thanintheendurancegroup，
the endurance−in the short・latency component．The
It，islikely that two possible mechanisms within the
vibration decreased the stretch reflex gainin both
neural pathway，preSynapticinhibition and／or the
groupsforbothshort・andmiddle−1atencycomponents
muscle spindle susceptibility are difEbrently adapted
andtherewerenodi飴rencesintheratioofthedecrease
depending on the types ofphysicalactivitiesin which
between the groups 魚）r both components． The
theyareengaged．
vibration decreased the amplitude ofH−reflexin both
groups，butthe ratio ofthe decrease was slgni丘cantly
greaterinthesprint−thanintheenduranCe￣grOup・
− 30 −

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