Correlation of Muscle Strength and Power with Gait in Elderly Women with Knee Osteoarthritis

Abstract

Older adults with knee osteoarthritis have decreased quadriceps strength, which is associated with decreased physical function. However, muscle power may be a better predictor of physical function than strength. Another predictor of physical function is gait velocity. Knee osteoarthritis’s patients walk more slowly and have a reduced stride length compared to healthy control subjects. Nevertheless, these gait parameters were not correlated to quadriceps muscle strength and power. PURPOSE: To compare the muscular strength and power of the knee extensors in elderly women between symptomatic and asymptomatic knee joint and to correlate muscular strength and power with cadence, gait speed, stride length and stride time. METHODS: Seventeen elderly women (67,05±5,35 years) with knee osteoarthritis performed an isokinetic test of quadriceps strength (60°/s) and power (180°/s). The kinemactics analyses were conducted to determine the following spatial and temporal gait variables at comfortable speed: cadence, gait velocity, stride length and stride time (Vicon®). To compare strength and power of the symptomatic and asymptomatic knee a paired t-test was applied. Pearson’s correlation was used to verify the correlations between strength and power of the symptomatic knee with spatiotemporal variables of gait (p<0,05). RESULTS: Quadriceps strength and power of symptomatic knee were lower than the asymptomatic knee (p<0,05). There was no correlation between quadriceps strength of symptomatic knee and gait’s spatiotemporal variables. However, correlations between quadriceps power of symptomatic knee and gait’s spatiotemporal variables were observed with cadence (r=0,509; p<0,05) and gait speed (r= 0,494; p<0,05). CONCLUSIONS: The present study showed that both quadriceps strength and power of symptomatic knee were lower than the asymptomatic knee. Additionally, quadriceps power was correlated with gait’s cadence and velocity. Further studies using different velocities are required to analyzed the gait parameters and its correlations with the lower limbs strength and power in elderly women with knee osteoarthritis.