Fig. 7.

Scaling of effects of torque waveform amplitude. A and B: recordings of the hindleg depressor and flexor in an animal that showed sustained activity following leg searching. Application of forces at lower (A) and higher (B) levels produced activation of both muscles. Both the force and rate of change of force (dF/dt) are simultaneously and proportionately increased. C and D: plot of the mean discharge frequencies of flexor (C) and depressor (D) muscles during series in which forces were applied at different amplitudes. Effects on motor discharges in both muscles were graded and reflected the torque increase.