Mediolateral trunk control, rather than temporal gait control, is associated with treadmill walking adaptation in...

Treadmill training improves gait performance and reduces fall risk in older adults; however, inter-individual variability in training response has been reported. Insufficient adaptation to treadmill walking may limit training effectiveness and potentially increase fall risk. This study aimed to identify baseline gait characteristics associated with adaptation to treadmill walking in healthy older adults. Seventeen older adults walked on a treadmill at 2.7 km/h for 5 min while wearing a triaxial accelerometer on the lower trunk and a foot switch on the right shoe. Walking data were segmented into ten 30-s bins. Treadmill adaptation was defined as the slope of the stride-time coefficient of variation (CV) across bins. Baseline gait characteristics were calculated from the first three bins and included the root mean square of mediolateral acceleration (RMS_ML; magnitude of mediolateral trunk acceleration), the mediolateral harmonic ratio (HR_ML; temporal symmetry), and stride-time CV (temporal consistency). Spearman's and exploratory partial Spearman's correlations adjusted for comfortable overground walking speed were performed. Treadmill adaptation was significantly correlated with baseline stride-time CV (ρ = -0.56) and RMS_ML (ρ = 0.52). After adjusting for comfortable walking speed, only RMS_ML remained significant (ρ = 0.50). Additionally, HR_ML demonstrated a significant correlation only after speed adjustment (partial ρ = -0.58). These findings suggest that lower mediolateral trunk acceleration at baseline is associated with early temporal stabilization during treadmill walking in healthy older adults.