There has been an explosion of research investigating the association between various indices of physical activity and markers of health, including body composition, with much of this research characterized by subjective measures and single cross-sectional assessments. The purpose was to examine relationships between multiple indices of energy expenditure (EE) and body composition (BC) using objective, clinical tools in a dual cross-sectional design. Males (n=14) wore the SenseWear PRO 2 armband (SP2) for two 3-day periods (T 1 , T 2 ) separated by 6 weeks. The SP2 measured four EE indices: total energy expenditure (TEE, kcal), physical activity energy expenditure (AEE, kcal), physical activity duration (PA, mins), and number of steps (STPS). DXA measured four BC indices: bone mineral content (BMC, g), lean soft tissue (LT, g), and adipose tissue (AT, %, g). Associations between EE and BC were examined using bivariate correlations. At T 1 , TEE was correlated with BMC (r= 0.841, p<0.001) and LT (r=0.638, p=0.014), while AEE was correlated with BMC (r=0.565, p=0.035). At T 2 , TEE was correlated to BMC (r=0.596, p=0.025), while AEE was associated with LT (r=0.535; p=0.049). TEE and AEE demonstrated consistent associations with fat free mass. Despite being key aspects of recommendations for health, physical activity duration and steps were not associated with any BC index nor was either index of fat mass associated with any measure of EE.