Effects of minimal shoes with and without insoles on static and dynamic stability across adults lifespan

Falls and balance impairments occur across the lifespan but are particularly problematic in older adults due to negative effects of ageing on several intrinsic factors. This study investigated the effects of minimal shoes without and with insoles on stability-related gait parameters, static stability and functional mobility across age groups to inform footwear characteristics that may reduce fall risk. A total of 142 healthy volunteers (62 young, 40 middle-aged and 40 older adults) completed timed up and go (TUG), 2-minute walk test (2-MWT) and bipedal standing tests under eyes open and closed conditions, in random order of five footwear conditions: habitual, barefoot, minimal shoes without insoles, minimal shoes with textured insoles and minimal shoes with supportive insoles (heel cups and arch support). Spatial-temporal, functional mobility from dynamic and centre of pressure (CoP) sway parameters from static tests were analysed across age groups and footwear conditions by Type III ANOVA using linear mixed-effects models. Post-hoc analysis compared estimated marginal means, with the false discovery rate (FDR) adjusted p values (p < 0.05). Barefoot increased overall task time in the TUG test. In the 2-MWT, older adults walked shorter distance and had reduced stride length across minimal shoes conditions (p < 0.001) compared to young and middle-aged adults. CoP parameters showed that older adults exhibited increased postural sway, while textured insoles reduced sway, but habitual shoes and supportive insoles increased sway across all age groups. Older adults dynamic tasks were more affected in barefoot and habitual cushioned shoes reduced their static stability, indicating that minimal shoes combined with targeted insoles design may offer a balanced approach to improve postural stability and reduce fall risk.