Knee extensor power predicts six‐minute walk test performance in people with transfemoral amputations

Background Lower‐limb amputees have increased metabolic costs during walking that may be mitigated by maintaining quadriceps strength and power following amputation. However, there are no current studies investigating the relationship between thigh strength and walking performance in individuals with transfemoral amputation. Objective To quantify the relationship between intact limb quadriceps strength in transfemoral amputees and six‐minute walk test (6MWT) performance. Design Descriptive laboratory study. Setting Laboratory. Participants Eleven participants with unilateral transfemoral amputations from trauma or osteosarcoma (4 women/7 men, 46.21 ± 12.68 years old, 28.24 ± 20.57 years following amputation). Interventions Strength and power testing on the intact limb followed by 6MWT with a flowmeter to measure oxygen uptake (VO2). Main Outcome Measures Strength included mass‐normalized peak torque, average torque, and average power. 6MWT measures included total distance traveled and VO2 normalized to distance and mass. Significant correlations (P ≤ .05) were retained for a regression analysis. Results Peak isokinetic knee extensor torque was correlated with total VO2 (r = −.60, P = .05) and distance traveled (r = .84, P = .001). Average isokinetic knee extensor torque was correlated with total VO2 (r = −.61, P = .046) and distance traveled (r = .85, P = .001). Average knee extensor power was correlated with total VO2 (r = −.67, P = .026) and distance traveled (r = .88, P