Biokinetical analysis of hind limb movements of the dog.

This study of movements of the hind limb of the dog was performed with the aid of cinephotography and electromyography. The weights of the limb segments and their centers of gravity were determined. From these data the forces operating at the centers of the limb segments during a cycle of a stride have been calculated and their influence on the joints have been analysed. From this study is concluded: 1) muscular activity is present when the effect of external forces must be overcome and subsides when these external forces act "positively" in the direction of the progression; 2) gravity and ground-reaction play an important role in the propulsion of the body, especially when there is no activity in the important retractors of the limb at the end of the support phase; 3) moments about the stifle and tarsal joints are opposite at the end of support phase and swing phase; 4) activity of the flexor digitorum superficialis (and also of the gastrocnemius muscles) during the support phase and of the peroneus longus muscle during the swing phase contribute to the coordination of the movements and to the stabilization of these joints.