OBJECTIVES: To compare relationships of appendicular skeletal muscle mass (ASM) with the function of the upper and lower extremities, after the former has been adjusted by five body size variables: height STUDY DESIGN: A cross-sectional study of data derived from the baseline phase of the Physical Activity and Health in Older Women Study. MAIN OUTCOME MEASURES: ASM was measured by bioelectrical impedance analysis. Grip strength and the time spent on the 5-times chair stand test (5-CST) were the evaluation indexes of upper and lower extremity function respectively. Standardized grip strength and log-transformed 5-CST were used as dependent variables, and standardized ASM adjusted by the five body size variables were used as independent variables. Multiple linear regression models then assessed the relationships of muscle mass with grip strength and 5-CST. RESULTS: 1103 community-dwelling women aged 60-70 years were included in this study. After adjustment for covariates, ASM adjusted by height CONCLUSIONS: Compared to ASM adjusted by the other four body size variables, ASM adjusted by weight/sitting height