The influence of lower-extremity muscle force on gait characteristics in individuals with below-knee amputations secondary to vascular disease

Background and Purpose. The purpose of this study was to establish the relationship between isometric muscle force and temporal-spatial gait characteristics for individuals who have had a below-knee amputation secondary to vascular disease. Subjects. Twenty-two individuals (15 male, 7 female) with dysvascular below-knee amputations participated. The male subjects were aged 35 to 72 years ((X) over bar=59.6, SD=11.1), and the female subjects were aged 54 to 68 years ((X) over bar=60.5, SD=5.1). Methods. The subjects underwent stride analysis during free-speed and fast walking, as well as bilateral isometric force testing of their remaining hip, knee, and ankle muscles. Results. Stepwise regression analysis revealed that hip extensor force on the amputated side was the only predictor of both free speed (r=.50) and fast speed (r=.72). Hip abduction force of the sound limb was correlated with cadence for both free-speed trials (r=.57) and fast-speed trials (r=.57). Sound-side knee extensor force was related to free-speed stride length (r=.44), whereas residual-limb knee extensor force predicted stride length during fast walking (r=.67). Conclusion and Discussion. These results indicate that adequate force is necessary in both residual and sound limbs to improve functional gait ability and that the hip extensors and abductors and the knee extensors should be emphasized in the rehabilitation of individuals with below-knee amputations.