Understanding the effects of aging on whole-body dynamic balance, trunk stability, functional mobility, and hip strength

Trunk stability can contribute to preserving balance and functional independence in older adults. This study aimed to (a) assess age- and sex-related declines in trunk stability, dynamic balance, hip strength, and functional mobility in participants aged 30-80, and (b) examine trunk stability contribution to balance and functional mobility in those over 60. One hundred and twenty-seven healthy and physically active individuals performed two posturographic protocols, the tandem stance test and the unstable sitting test to assess whole-body dynamic balance and trunk stability, respectively, besides a functional mobility test through the modified Timed Up & Go test and a dynamometer test to measure hip strength. Linear regression analysis was used to evaluate the relationship between all variables and ages. Subsequently, one-way ANOVAs to assess between-sex differences and a correlation analysis were performed to examine the potential relationship of unstable sitting posturographic test performance with the modified Timed Up & Go and tandem stance posturographic tests performance in participants over 60 years of age. The main results were that trunk stability and whole-body dynamic balance showed a linear decline with age in males (R² = 71% and 45%, respectively) and females (R² = 46% and 40%, respectively). Participants also showed a linear reduction in functional mobility and hip strength for males (R² = 15% and 36%, respectively) and females (R² = 19% and 38%, respectively). The correlation analysis showed that trunk stability was the most relevant factor for whole-body dynamic balance (r = 0.629, p < 0.013), relative to hip strength which showed no association. By contrast, the hip strength was the most determinant factor for functional mobility (r = - 0.552, p < 0.013), especially in males (r = - 0.730, p < 0.013). Better trunk stability during the unstable sitting task is linked to improved tandem stance balance, while greater hip strength is associated with a faster Timed Up & Go performance in active older adults. These findings highlight the potential of targeted interventions, such as unstable sitting exercises to boost trunk control and hip strengthening protocols, to enhance dynamic balance and functional mobility. Early monitoring of these capabilities may play a relevant role in guiding exercise strategies for preventing physical decline in aging populations.