The Human Elbow and Knee: Functional Relationships and Phylogenetic Considerations

The knee and elbow flexion and extension maximum torque (T. max), total work and average power outputs of male and female subjects (n = 20) were obtained through isokinetic dynamometry. Although male exceeded female subjects in absolute torque, work and power output, male knee T. max and work output per kilogram of body weight did not differ from female. When elbow data were compared in this fashion, males remained higher than females. The extension/flexion ratio (for T. max and work) differed for knee (≃ 2:1) and elbow (≃ 1:1). Males and females responded similarly, in this respect. Several comparisons of knee and elbow turning force capacity were drawn which lead to an appreciation of the knee as a specialized locomotor joint and the elbow as a generalized joint to assist in manipulation. Phylogenetic inferences relative to locomotor evolutionary patterns are expressed.