The aims of this study were to describe age- and sex-related differences in total body skeletal muscle (TB-SM) mass and to determine the variance explained by physical activity (PA). This cross-sectional study included 401 males and 402 females, aged 60–79 years. TB-SM was determined by dual-energy x-ray absorptiometry (DXA) and PA by Baecke questionnaire. Statistical analysis included t test, ANOVAs, Pearson correlations, and multiple regression analysis. TB-SM mass was higher in the youngest age group when compared with the oldest in males and females. Males had greater TB-SM values than females. PA made a significant and positive contribution to the variation in TB-SM, β = 0.071; p = .016. Sex, height, fat mass, and PA explained 77% of the variance in TB-SM. The oldest cohorts and females had lower TB-SM than the younger cohorts and males. This study suggests that PA exerts a significant role in the explanation of TB-SM.
É.R. Gouveia and Freitas are with the Department of Physical Education and Sport, University of Madeira, Funchal, Portugal. B.R. Gouveia is with Saint Joseph of Cluny Higher School of Nursing, Funchal, Portugal. Maia is with CIFI2D, Faculty of Sport, University of Porto, Porto, Portugal. Blimkie is with the Department of Kinesiology, Faculty of Science, McMaster University, Hamilton, Ontario, Canada. Freitas is also with the Department of Mathematical Sciences, University of Essex, Colchester, United Kingdom.
Address author correspondence to Élvio Rúbio Quintal Gouveia firstname.lastname@example.org.