Fig. 4

Fatigue testing. a Comparison of the fatigue development over 180 contractions using different electrode configurations. The means of all normalized peak-torque (solid traces) and normalized average-torque (doted traces) are presented for each electrode configuration (n ≥ 5). For a better readability, SD is not shown in the diagram. b Representative example of active torque traces throughout the extension/flexion cycle. The first 10 contractions (blue traces), in contrast to the last 10 contractions (red traces) are depicted along with the knee-extension-angle (black dashed trace). Stimulation was active during extension from 75° to 125° knee-extension angle and is highlighted in light orange