Fig. 5.

The time course of force decrements (e^−kt) were twice as rapid in the 0.6 vs. 0.3 duty cycle condition (A and C). In contrast, when trial durations were expressed as the cumulative duration of muscle force production only, these differences were eliminated (B). For instance, trials representing the midpoint of the nonsustainable performance range occurred for durations of 35.6 vs. 67.2 s, respectively (C; P < 0.001). However, the levels of force production eliciting this midpoint were reached with nearly the same cumulative durations of muscle activity [22.4 vs. 20.2 s, respectively (P = 0.30); C].