Analyses of treadmill locomotion in adult spinal dogs

The locomotion of the hindlimbs of two adult female spinal dogs, who were able to walk steadily on their hindlimbs 10 months after transection of the spinal cord (T10), and of two normal dogs was analyzed on a treadmill by means of high-speed cinematography and electromyography. With increase in walking speed, the duration of the step cycle was shortened by reduction of the duration of the stance phase, and the stride length was extended mainly by elongation of the transfer distance during the swing phase in both normal and spinal dogs. The patterns of muscle discharges of the hindlimbs in spinal dogs were similar to those in normal dogs. With increase in walking speed, reductions in the burst duration of the extensors were observed in both normal and spinal dogs. These results indicate that spinal dogs can adjust their locomotion speed in the same manner as normal dogs; this supports the theory that a central pattern generator regulating the locomotive activities of the hindlimbs exists in the spinal cord below the transection site.