Influence of Lower-extremity Muscle Force, Muscle Mass and Asymmetry in Knee Extension Force on Gait Ability in Community-dwelling Elderly Women

The purpose of this study was to examine the influence of muscle mass/power of the lower-extremities, including asymmetry in knee extension force, on gait ability of Japanese community-dwelling elderly women. The study population comprised 30 women aged 65-89 years. The parameters examined were activities of daily living, physical performance, functional capacity, isometric muscle forces of knee extension and flexion measured by a dynamometer, and muscle mass measured by bioelectrical impedance analysis. Asymmetry in knee extension force was calculated from rate of difference between the right and the left knee extension forces. One leg balance with eyes open, 6-minute walking distance (6MD) and knee extension force decreased, while 10-m obstacle walking time and asymmetry in knee extension force increased with age. Gait ability including 6MD and 10-m obstacle walking time correlated with asymmetry in knee extension force, which also exhibited correlations with one leg balance with eyes open and knee extension force. The results of the present study indicate that on increase in asymmetry in knee extension force as well as a decrease in lower-extremity muscle force might accelerate the loss of gait ability, while the improvement of asymmetry in knee extension force might be beneficial to self-supporting life in elderly individuals.