Little is known about skeletal muscle distribution in healthy adults. Data were collected on 132 healthy, ambulatory, Caucasian women and men, aged 20-89 yr. Appendicular skeletal muscle mass multiple regression models were developed to assess the relationships between regional skeletal muscle and height, weight, age, ethnicity, and extremity lengths.
Results: (1) with an increase in body weight there is a greater relative increase in upper muscle distribution; (2) women have less upper muscle mass compared to men; (3) with increasing age there is a relative reduction in upper muscle distribution. The present results indicate that skeletal muscle is not a homogenous component, but has at least three independent factors, gender, weight, and age, influencing distribution.