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

[摘要] ENGLISH ABSTRACT: The concentric hamstring quadriceps reciprocal muscle group ratio hasbeen the focus of a very large part of studies involving isokineticdynamometry. The main aim of this study was to reevaluate the functionalrelevance of this ratio and explore a strength ratio between maximal eccentricstrength of the hamstrings and the concentric strength of the quadricepsmuscle groups, referred to as the functional dynamic stability ratio. At thesame time the inter-relationship between the eccentric and concentricstrength of the same muscle group (critical deficit ratio) was investigated.As background a detailed discussion of research concerning theconventional hamstring quadriceps ratio and the biomechanics of the kneejoint and musculature was presented. The importance of the eccentricstrength of the hamstring muscle group regarding functional muscle actionand anterior cruciate ligament stability was also discussed. The functionaldynamic stability ratio was hypothesised to be a 1: 1 ratio due to thesimultaneous concentric quadriceps and eccentric hamstring musclecontraction during walking, jogging and running activities.The bilateral concentric and eccentric peak torque of the hamstringsand quadriceps muscle groups of 45 (N=45) rugby players were evaluatedusing a Kin-Com© isokinetic dynamometer. The calculated averageconcentric reciprocal muscle group ratio was (0.64, SD=0.15) andeccentrically (0.61, SD=0.15). The average functional dynamic stability ratioresulted to 0.77 (SD= 0.14) for the left leg and 0.79 (SD= 0.16) for the rightleg.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. Thefunctional dynamic stability ratio was found to be striving towards a 1:1 ratio toachieve optimal knee joint and hamstring integrity.

[发布机构] Stellenbosch University