Objective With increasing global aging, the relationship between gait and cognitive function has become a research priority. Although spatiotemporal differences in dual-task (DT) gait are well-documented, studies on kinetics remain limited. This study aimed to explore age-related changes in kinetics under cognitive load. Methods This study is a prospective cross-sectional study. Thirty-six participants were categorized into 3 groups: young (YG, 18-37 years), middle-aged (MG, 38-57 years), and elderly (OG, ≥ 58 years), with 12 in each group. Gait tests were conducted under single-task (ST) and DT conditions. The DT involved counting down by 1 from a random number of 100 while walking. Kinetics includes forces, moments, power, and center of mass (CoM). Repeated measures general linear model was used to assess effects of tasks on age groups. Group differences in DT gait cost (DTGC) were examined by MANOVA with Bonferroni corrections. Results OG showed increased ankle medial-lateral force, decreased knee external rotation moment (p = 0.049), and reduced hip anterior force and power (p < 0.01). MG exhibited reduced hip power (15.4%) and force in multiple directions (p < 0.05), while YG had decreased hip abduction–adduction moment (p = 0.004). In the medial-lateral of CoM, OG had significantly lower motion of range in ST than in DT (p = 0.028). DTGC comparisons showed that OG had the biggest kinetic changes under DT, MG followed, and YG had the least impact. Conclusions This study showed that the impact of cognitive load on kinetics differs across age groups. The OG relied on ankle joint compensation but with lower efficiency, leading to decreased gait stability. The MG adjusted gait using both the ankle and hip joints, while the YG showed minimal changes and stable gait. DT gait assessment shows that older adults use different strategies in their lower limbs. This highlights its potential to detect mobility decline early.
Zhang et al. (Wed,) studied this question.