Sagittal-hip-muscle power during walking in old and young able-bodied men

In this study, tasks of the hip in elderly and young gait were identified u sing principal-component analysis (PCA). Discrepancies between older and yo unger participants for hip-flexor and -extensor action during stance were a lso investigated. PCA was applied to the sagittal-hip-muscle-power curves o f participants. Three principal components (PCs) were retained far further analysis. A t test revealed that all measures of gait spatiotemporal parame ters were significantly lower in the older participants (p < .05). The firs t PC for both groups extracted the largest variation and described hip-powe r action during midstance. The second and third PCs in the older participan ts highlighted the role of the hip extensors and flexors during weight acce ptance, late stance, and pull-off. The corresponding PCs for the younger pa rticipants were mainly associated with hip-extensor/flexor action during pu ll-off and weight acceptance. The results indicate that the hip-extensor/fl exor muscles are mainly responsible for balance control in elderly gait but contribute to both balance control and propulsion in the gait of younger i ndividuals.