Fig. 3. Schematic representation of the stretching tests on the descending limb of the force—length relationship of the cat soleus muscle. Muscles were stretched for 3, 6 and 9 mm (approx. 7, 14 and 21 % of optimal fibre length) at speeds of 3, 9 and 27 mm s^-1 (approx. 7, 21 and 63 %, respectively, of optimal fibre length s^-1). For all tests, the muscle was activated for 9 s at 3T (3x the alpha-motoneuron threshold) starting at time 0 s. Steady-state total force enhancement following stretching was always determined 4.5 s after the end of the dynamic phase of contraction (i.e. at 8.5 s, see first arrowhead). Passive force enhancement following stretching was always determined 3s after activation had been stopped (i.e. at 12s, see second arrowhead).