Figure 1.

Force–time plots of an isometric contraction (i) of dogfish muscle at 34 mm length, and an isometric stretch–isometric contraction (s) in which the muscle is stretched from 29 to 34 mm (about 15% stretch) at time 3–9 s. Note that the steady-state isometric force following stretch is greater than the corresponding force of the purely isometric contraction at the same length. This so-called ‘steady-state’ or ‘residual force enhancement’ is indicated as ΔF. Muscle temperature 0°C, stimulation frequency 5 Hz. Adapted from Abbott & Aubert (1952) with permission.