Fig. 1.
Panels on the left: profile of mechanical power absorbed (negative) and generated (positive) by the MTU (upper panel), muscle fascicle (middle panel) and Achilles tendon (lower panel) during the stance phase at the investigated running speeds (solid line: 10 km h−1; dotted line: 13 km h−1; dashed line: 16 km h−1). Note that the mechanical power absorbed by the Achilles tendon is always higher than that returned during its recoil. Panels on the right: positive mechanical work done by the MTU (upper panel), muscle fascicle (middle panel) and Achilles tendon (lower panel) during the stance phase at all the investigated running speed. Positive work was calculated as the first integral of the positive mechanical power generated during the stance