Figure 3. Shortenings after a series of concentric or eccentric contractions.

Tension changes during a 6 mm shortening of the muscle at 10 mm s⁻¹. The shortening step began after 0.25 s of isometric contraction, using stimulation at 140 pps (continuous trace) or 80 pps (dotted trace) or 50 pps (dashed trace). Measurements were made at the start of the experiment (Pre), after a series of 200 concentric contractions (Conc) or after a series of 10 eccentric contractions (Ecc). The continuous trace at the bottom indicates muscle length, the shaded bar, the period of stimulation.