Figure 1.

(a) Example stiff-knee flexion–extension pattern (dashed line) compared to a normal knee angle during a stride (solid line). The stiff-knee gait pattern has an extremely limited dynamic range of motion and absence of appropriate knee flexion in the swing phase. Reproduced with permission from Sutherland and Davids21. (b, c) Examples of leg configuration at onset of push-off in normal and crouch gait, showing that knee angles can differ vastly, which may affect the progression of the leg into swing. Pictures are from a separate experimental study