Associations between water-based exercise and resistance training with body composition and bone mineral density in older women: a cross-sectional study

BACKGROUND: Aging is associated with decreases in lean mass and bone mineral density (BMD), increasing the risk of sarcopenia and fractures. Resistance training (RT) and water-based exercise (WE) are recommended; however, their comparative associations in older women remain unclear. This cross-sectional study examined body composition and DMO in older women practicing RT, WE, or not engaged in structured exercise. METHODS: This study included 67 elderly women (70.5 ± 7.10 years) allocated to a RT group (RTG, n=18), WE group (WEG, n=23), and inactive group (IG, n=26). Body composition and BMD (total body, lumbar, femoral neck, forearm) were assessed by DXA and estimated skeletal muscle mass index (SMMI) was estimated. Group-related differences were analyzed using one-way ANOVA with Tukey post hoc tests (α = 0.05). RESULTS: Both active groups were associated with greater lean mass compared to IG (RTG: + 30.9%; p = 0.006 and WEG: + 24.9%; p = 0.006). However, only RTG was associated with higher SMMI, being 13.4% (p < 0.001) higher than WEG and 9.0% (p = 0.018) than IG. Likewise, RTG presented higher whole-body BMD (in relation to WEG: + 4.2%; p = 0.012 and IG: + 8.6%; p = 0.029) and femoral neck BMD (in relation to WEG: + 13.4%; p = 0.006 and IG: 12.2%; p = 0.012). CONCLUSIONS: RT and WE were associated with more favorable body composition and BMD profiles in older women, with stronger associations observed for RT. Causal inferences cannot be made due to the cross-sectional design.