Analysis of Association between Appendicular Skeletal Muscle Mass, Physical Performance and Mechanical Properties of Lower Extremity Muscles in Older Women

PURPOSE: This study aimed to investigate the relationships among appendicular skeletal muscle mass (ASM), physical performance, and the mechanical properties of lower-extremity muscles in older women, with the goal of preventing physical functional decline due to aging and providing foundational data for sarcopenia management.METHODS: This study included 34 women aged ≥70 years. Physical performance was assessed using grip strength and the Short Physical Performance Battery, while the mechanical properties of the lower extremity muscles were measured using a soft tissue measurement device (Myoton Pro, Estonia) to assess the elasticity, tone and stiffness of the tibialis anterior (TA) and gastrocnemius medialis (GM) muscles. Correlation analysis was conducted between ASM and all variables; multiple regression analysis was performed on the variables that showed significant correlations.RESULTS: ASM was positively correlated with body weight (r=0.821, p=.001), BMI (r=0.784, p=.001), calf circumference (r=0.765, p=.001), and TA elasticity (r=0.393, p=.021). ASM correlated negatively with TA tone (r=-0.478, p=.004), GM tone (r=-0.368, p=.032) and GM stiffness (r=-0.404, p=.018). Multiple linear regression analysis indicated that ASM was positively influenced by body weight (78.7%) and negatively influenced by GM stiffness (32.1%). Specifically, a 1-unit increase in body weight led to a 0.047 increase in ASM, while a 1-unit increase in GM stiffness was associated with a 0.004 decrease in ASM.CONCLUSIONS: Our results suggest that excessive weight loss in older women may decrease ASM and increase gastrocnemius muscle stiffness, negatively impacting walking ability.