Leg extension power asymmetry and mobility limitation in healthy older women.

OBJECTIVE

To investigate the association of asymmetry in leg extension power (LEP) with walking and standing balance.

DESIGN

Cross-sectional analysis.

SETTING

Research laboratory.

PARTICIPANTS

Healthy female twins (N=419), ages 63 to 75 years.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The LEP difference between the stronger and the weaker leg, measured with the Nottingham power rig, was calculated. Ten-meter maximal walking velocity was assessed in a laboratory corridor on a wide (170 cm) and narrow (35 cm) track, and the ability to maintain tandem stance for 20 seconds was recorded.

RESULTS

The mean LEP difference +/- standard deviation between the legs was 15%+/-9% (P<.001). Those with large LEP difference had lower walking velocity and poorer standing balance than those with small LEP difference, in particular when the LEP of the stronger leg was below the median.

CONCLUSIONS

Even in healthy older women, substantial LEP asymmetry between the lower limbs was present, encumbering walking and standing balance. Lower-limb muscle power asymmetry warrants further study in order to develop well-targeted strategies for preventing mobility limitation in older people.