Training-induced strength and functional adaptations after hip fracture

Abstract

Background and purpose: At 3 months after hip fracture, most people are discharged from physical therapy despite residual muscle weakness and overall decreased functional capabilities. The purposes of this study were: (1) to determine, in frail elderly adults after hip fracture and repair, whether a supervised 6-month exercise program would result in strength gains in the fractured limb equivalent to the level of strength in the nonfractured limb; (2) to determine whether the principle of specificity of training would apply to this population of adults; and (3) to determine the relationship between progressive resistance exercise training (PRT) intensity and changes in measures of strength and physical function.

Subjects: The study participants were 31 older adults (9 men and 22 women; age [X+/-SD], 79+/-6 years) who had surgical repair of a hip fracture that was completed less than 16 weeks before study enrollment and who completed at least 30 sessions of a supervised exercise intervention.

Methods: Participants completed 3 months of light resistance and flexibility exercises followed by 3 months of PRT. Tests of strength and function were completed at baseline, before PRT, and after PRT.

Results: After PRT, the subjects increased knee extension and leg press 1-repetition maximum by 72%+/-56% and 37%+/-30%, respectively. After 3 and 6 months of training, lower-extremity peak torques all increased. Specificity of training appeared to apply only to the nonfractured limb after PRT. Strong correlations were observed between training intensity and lower-extremity strength gains as well as improvements in measures of physical function.

Discussion and conclusion: Frail elderly adults after hip fracture can benefit by extending their rehabilitation in a supervised exercise setting, working at high intensities in order to optimize gains in strength and physical function.