Ipsilateral limb variation in cats during overground locomotion.

The timing interval between the onset of knee extensor EMG (vastus lateralis) and the onset of the ipsilateral elbow flexor EMG (brachialis) was studied in adult cats during overground walking, trotting and galloping. Concurrent finding of the animals in locomotion was used to relate the electrical activity of the muscles to the physical events in a step cycle. The observed variability in the interval between the onset of knee extensor EMG and the onset of elbow flexor EMG lead to the conclusion that it is not appropriate to postulate a rigid neural coupling mechanism for the control and coordination of ipsilateral limbs in locomotion.