Fig. 8. Effects of muscle relative position of fully dissected in situ rat medial gastrocnemius (GM) muscle on force. Muscle relative position was manipulated by moving the origin 3 mm proximally or distally from the reference position (i.e. the position corresponding to a knee angle of 120°). (A) Active force-length characteristics after moving the origin in the proximal direction. (B) Passive force-length characteristics after moving the origin in the proximal direction. (C) Active force-length characteristics after moving the origin in the distal direction. (D) Passive force-length characteristics after moving the origin in the distal direction. Proximal and distal forces (mean ± S.E.M.) are represented by closed and open symbols, respectively. Muscle-tendon complex length (L_m+t) is expressed as deviation from optimum length (L₀).