Fig. 3. Fibre length (A) and force (B) changes of a preparation that was first made to shorten isotonically under five different afterloads, and then subjected to quick releases at 1 s after activation to drop the force to zero. After each release, the preparation redeveloped isometric force at the decreased fibre length. Length recordings a–g correspond to force recordings a'–g', respectively. The load was P_o (isometric condition; b, b'), 0.63 P_o (c, c'), 0.41 P_o (d, d'), 0.20 P_o (e, e'), 0.09 P_o (f, f'), 0 P_o (unloaded condition; g, g'). Recordings a, a' were obtained during isometric contraction without quick release.