Leg extension power deficit and mobility limitation in women recovering from hip fracture.
Portegijs E., Sipilä S., Rantanen T., Lamb SE.
OBJECTIVE: After hip fracture, muscle strength and power remain persistently poor, especially in the fractured leg. This study explores whether asymmetrical leg extension power (LEP) deficit affects mobility in women after proximal femoral fracture (PFF). DESIGN: In this observational study, LEP of both legs, 10- and 50-foot walking speed, and stair-climbing speed were measured in 43 women, aged 73-96, at 1 and 13 wks after surgical repair of PFF. Asymmetrical LEP deficit was calculated as (fractured/(sum both legs)) x 100%. RESULTS: Between weeks 1 and 13 after PFF surgery, LEP increased in the fractured and nonfractured legs by 100% and 30%, respectively. Asymmetrical deficit was reduced from 28.5 +/- 10.2% to 40.4 +/- 8.6%. Linear regression analyses showed that poorer LEP of the nonfractured leg at week 1 correlated significantly with slower walking (beta > 0.525, P < 0.001) and stair-climbing speed (beta > 0.349, P < 0.016) and predicted poorer mobility 12 wks later (beta > 0.354, P < 0.020). Large asymmetrical LEP deficit was cross-sectionally associated with slow stair-climbing speed (beta > 0.343, P < 0.018) at weeks 1 and 13, but not with walking speed. CONCLUSIONS: Higher LEP of the nonfractured leg predicted better recovery of mobility after PFF. Larger asymmetrical LEP deficit correlated with limitation in climbing stairs-a more challenging mobility task where fluent performance requires unilateral force production.