Three-dimensional kinematic technique for evaluation of horse locomotion in outdoor conditions

THE KINEMATICS of equine locomotion has been studied for quite some time. Muybridge and Marcy were the first to use the newly available photographic technology to document the gait of horses (MUYBRIDGE, 1887 and MAREY, 1894). Owing to the significance of lameness in horses and its economic significance for the horse industry, kinematics has been studied using increasingly sophisticated techniques adapted from human biomedical research (LEACH and DAGG, 1983; LEACH, 1987; CLAYTON, 1991). Horses present some particularities which make the study of their locomotion similar to that of the human athlete. Owing to their size and the amplitude of their movements, a broad field of view is required. Consequently, the captors have to be situated far from the horse subject, thus limiting the use of many human gait analysis systems. There are few kinematic analysis systems currently used for horse locomotion evaluation. They are divided into cinematographic, opto-electronic and video systems. Cinematography has been used in several studies. The locomotion of Standardbreds running at high-speed (12 m s l ) has been studied (FREDEKICSON and DREVEMO, 1972; DREVEMO et aL, 1987). The locomotion of race horses has been analysed using 16 mm high-speed cameras (LEACH et al., 1984; CLAYTON, 1989; HOLMSTROM et aL, 1994). The technique has also been applied to lameness evaluation (CLAYTON, 1986; GmTLER, 1988; KOBLUK, 1989). The advantages of this method are the high resolution and the frame rates (between 100 and 500 Hz) of the cinematographic cameras. However, this method requires film processing, thus increasing the cost and time of analysis. Moreover, cinematography appears to be quite expensive and the above studies were made with a single camera. The 3-I3 reconstruction and the simultaneous comparison between both sides of the horse were impossible.