Training-Induced Strength and Functional Adaptations After Hip Fracture

Abstract

Background and PurposeAt 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.SubjectsThe study participants were 31 older adults (9 men and 22 women; age [X̄±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.MethodsParticipants 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.ResultsAfter 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 ConclusionFrail 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.