A study on the formation of center of gravity trajectory during sit-to-stand motion with asymmetrical foot placement

Abstract

processed with a wavelet analysis. The angular information of the Biodex dynamometer was synchronized with the telemetric transmitter during the muscle fatigue assessment. Owing to the high variance in the sEMGand isokinetic torque assessment data of the first and final (the 1st and the 32nd) repetitions of maximum knee extension, data from these two repetitions were excluded. The rates of the muscle fatigue and the sEMG spectral shape were calculated as the decline in each contraction number by the bivariate liner regression. Skeletal muscle mass (SMM) was assessed by the bioelectrical impedance analysis. All the assessment procedures in this study were administered to all subjects by one investigator. Results: The fatigue index was not significantly different in genders (males = 26.15± 2.65%, females = 18.73± 5.98%, effect size = 1.61, β = 0.394). The VL was significantly decreased linearly in the sEMG of mean-frequency (MNF) and high-frequency power(HF) for males and females. In addition, the Males exhibited higher reduction in MNF and HF than females. The males SMM values were significantly higher than females (males = 31.36± 1.86 kg, females = 20.04± 0.37 kg, p< 0.01, effect size = 7.56). Conclusion(s): This study demonstrated that there is a significant reduction in sEMG of MNF and HF in males. This data suggests that males have a higher percentage of fast-twitch muscle fibers than females. Implications: Physical therapist engaged in rehabilitation should be aware of the gender-difference during resistance training or muscle assessment.