Reciprocal muscle group and functional dynamic stability ratios of the hamstrings and quadriceps muscle groups during maximal isokinetic concentric and eccentric contractions

Surmon, Sean Henry (1999-12)

Thesis (M.Mbk.) -- University of Stellenbosch, 1999.

Thesis

ENGLISH ABSTRACT: The concentric hamstring quadriceps reciprocal muscle group ratio has been the focus of a very large part of studies involving isokinetic dynamometry. The main aim of this study was to reevaluate the functional relevance of this ratio and explore a strength ratio between maximal eccentric strength of the hamstrings and the concentric strength of the quadriceps muscle groups, referred to as the functional dynamic stability ratio. At the same time the inter-relationship between the eccentric and concentric strength of the same muscle group (critical deficit ratio) was investigated. As background a detailed discussion of research concerning the conventional hamstring quadriceps ratio and the biomechanics of the knee joint and musculature was presented. The importance of the eccentric strength of the hamstring muscle group regarding functional muscle action and anterior cruciate ligament stability was also discussed. The functional dynamic stability ratio was hypothesised to be a 1: 1 ratio due to the simultaneous concentric quadriceps and eccentric hamstring muscle contraction during walking, jogging and running activities. The bilateral concentric and eccentric peak torque of the hamstrings and quadriceps muscle groups of 45 (N=45) rugby players were evaluated using a Kin-Com© isokinetic dynamometer. The calculated average concentric reciprocal muscle group ratio was (0.64, SD=0.15) and eccentrically (0.61, SD=0.15). The average functional dynamic stability ratio resulted to 0.77 (SD= 0.14) for the left leg and 0.79 (SD= 0.16) for the right leg. Critical deficit ratios were 1.26 (SD=0.26) for the right hamstring, 1.33 (SD=0.210 right quadriceps, 1.28 (SD=0.21) lefts hamstring and 1.29 (SD=0.17) for the left quadriceps muscle groups. Values obtained were in accordance to that of available research. The functional dynamic stability ratio was found to be striving towards a 1:1 ratio to achieve optimal knee joint and hamstring integrity.

AFRIKAANSE OPSOMMING: Die groter deel van studies in die veld van isokinetiese dinamometrie, was meesal oor die konsentriese hamstrings quadriceps spierkrag verhouding. Menslike beweging tydens hardloop aktiwiteite en die gepaartgaande spierkontraksies toon egter dat die hamstring eksentries en die quadriceps konsentries tergelyke tyd saamtrek. Die doel van hierdie studie was dus om die funksionaliteit van die tradisionele hamstring quadriceps kragverhouding te re-evalueer en die moontlikheid van 'n funksionele dinamiese stabiliteits verhouding tussen die eksentries krag van die hamstrings en konsentriese krag van die quadriceps te ondersoek. Ook is daar ondersoek ingestel op die verhouding tussen die eksentriese en konsentriese krag van dieselfde spiergroep. As agtergrond is die konvensionele hamstring quadriceps verhouding ondersoek in die lig van kniegewrig biomeganika tydens stap, draf en hardloop aktiwiteite. Die noodsaaklikheid van eksentriese hamstring spierkrag vir funksionele spierkontraksie en anterior kruisligament stabiliteit was ook ondersoek en bespreek. Die gevolglike hipotese was dat die maksimale eksentriese krag van die hamstrings en die konsentriese krag van die quadriceps strewe na 'n 1: 1 verhouding vir optimal knie gewrig en spier funksie. Die maksimale konsentriese en eksentriese krag (hamstring en quadriceps spiergroepe) van 45 (N=45) rugbyspelers is m.b.v. 'n Kin-Com© isokinetiese dinamometer getoets. Die konvensionele hamstring quadriceps gemiddelde konsentriese verhouding was (0.64, SA=0.15) en eksentries (0.61, SA=0.15). Die gemiddelde funsionele dinamiese stabiliteits verhouding wat bereken is, was 0.77 (SA= 0.14) vir die linker been en 0.79 (SD= 0.16) vir die regter. Al die verhoudings wat ondersoek en bereken is, het ooreengestem met beskikbare literatuur. Die funksionele dinamiese stabiliteits verhouding het inderdaad 'n neiging getoon om te strewe na 'n 1: 1 verhouding vir optimale knie funksie.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/51402
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