In this study, tasks of the hip in elderly and young gait were identified using principal-component analysis (PCA). Discrepancies between older and younger participants for hip-flexor and -extensor action during stance were also investigated. PCA was applied to the sagittal-hip-muscle-power curves of participants. Three principal components (PCs) were retained for further analysis. A t test revealed that all measures of gait spatiotemporal parameters were significantly lower in the older participants (p < .05). The first PC for both groups extracted the largest variation and described hip-power action during midistance. The second and third PCs in the older participants highlighted the role of the hip extensors and flexors during weight acceptance, late stance, and pull-off. The corresponding PCs for the younger participants were mainly associated with hip-extensor/flexor action during pull-off and weight acceptance. The results indicate that the hip-extensor/flexor muscles are mainly responsible for balance control in elderly gait but contribute to both balance control and propulsion in the gait of younger individuals.