FIG. 4.

Heterogenic inhibition from G onto FHL, where G is the donor muscle and FHL is the recipient muscle in 1 animal during locomotion with force oscillations for the mechanical phase (A), dynamic phase (B), and static phase (C). • and ▵, FHL force responses from stretches occurring in ramp-and-hold stretch alone (R) and stretching the recipient and donor muscles simultaneously (RD), respectively. Polynomials and 95% confidence intervals are fit to each population of data, and statistical tests reveal that the populations for the dynamic and static phases are distinctly separated (P < 0.01). Two traces matched at 10 N background force in FHL from R (—) and RD (- - -) have been superimposed in the inset of B and C to illustrate the magnitude of inhibition from G onto FHL during locomotion, and the vertical line indicates the sample time. Heterogenic inhibition from G onto FHL is more force-dependent during the dynamic phase than during the static phase. The magnitude of heterogenic inhibition onto FHL for the dynamic and static time points (D) are represented as the difference between polynomials depicted in B and C.