Figure 3.

Backward quadrupedal or bipedal locomotion in intact and spinal cats at 0.2 m/s. A, EMG activity from nine hindlimb muscles along with stance phases (horizontal thick lines) of the left (L) and right (R) hindlimbs in one cat in the intact state during quadrupedal (BW-quadrupedal-intact or BQI) and bipedal (BW-biped-intact or BBI) backward locomotion and after spinal transection in the bipedal condition (BW-biped-spinal or BBS). Data are from Cat 5 before and six weeks after spinal transection. For muscle abbreviations, see Figure 1. B, Cycle, stance and swing durations in the three conditions. C, Stride and step lengths in the three conditions. D, Distance at contact and liftoff in the three conditions. EMG burst durations (E) and phasing (F) in the three conditions. B–F, Each data point or bar is the mean ± SD for the group (n = 3 cats), whereas statistical analyses were done on pooled cycles/bursts. BQI (n = 20 cycles/bursts), BBI (n = 29 cycles/bursts), BBS (n = 34 cycles/bursts). Asterisks indicate a significant effect of condition (MLM) at *p < 0.01, **p < 0.001, ***p < 0.0001; ns, not significant.