Fig. 8. Total joint power (tot, solid colored lines), external joint power (ext, dotted colored lines) and summed limb power (broken black lines) for the representative trials shown in Fig. 6. The majority of the power for changing speed is produced at the hip (red) and ankle (blue). Peak powers at the knee (green) increase during accelerations and decelerations, but the net work remains relatively constant. The MP (black) produces more negative power with increased accelerations.