Trunk movements and EMG activity in the cat: level versus upslope walking.

This chapter addresses the neural control of spinal-column behavior during locomotion. Kinematic and EMG measurements were obtained from the adult cat during its level and upslope treadmill walking. Increasing the grade of upslope walking augmented horizontal movements of the spinal column and decreased its lateral movements. In conjunction, there were significant increases in the amplitude, duration, and pattern of EMG bursts in relevant spinal column musculature. During even steeper upslope walking, three EMG bursts were evident. They were phase-locked to the outward, downward and backward movements of the spinal column, respectively. Our results suggest that the component of the locomotor pattern generator that produces rhythmical spinal column movements must generate a wide variety of EMG bursts in spinal column muscles, as dependent in part on sensory input from the spinal column and its musculature.