Physical Activity, Muscle Mass, and Bone Mineral Density in Older Adults: A Cross-Sectional Study

Introduction: The rising number of older adults each year poses significant public health challenges, particularly regarding musculoskeletal decline that reduces independence and quality of life. Muscle mass, bone mineral density (BMD), and physical activity are critical determinants of musculoskeletal health. This study aimed to examine the associations between physical activity, muscle mass, and BMD among older adults at Tamalanrea Primary Health Center, Makassar. Methods: A cross-sectional study was conducted involving 133 purposively selected older adults. Physical activity was assessed using the standardized International Physical Activity Questionnaire (IPAQ). Muscle mass and BMD were measured using bioelectrical impedance analysis (BIA). Associations were tested using Somers’ D, and correlation coefficients were calculated to determine the strength and direction of the relationships. Results: Most participants demonstrated low to moderate levels of physical activity. Significant associations were observed between physical activity and muscle mass (p < 0.001, r = –0.530), as well as between physical activity and BMD (p = 0.002, r = –0.263). Negative correlations indicated that higher physical activity levels were linked with lower measured muscle mass and BMD, contrasting with previous findings that commonly reported positive associations. Conclusion: Physical activity showed significant but inverse associations with muscle mass and BMD in older adults. Further studies are warranted to clarify underlying mechanisms and reconsider the role of physical activity in maintaining musculoskeletal health in aging populations.