Validation of a Three Dimensional Motion Capture System for Use in Identifying Characteristics of the Running Walk

The objective of this experiment was to assess differences between the walk (W) and running walk (RW) of the Tennessee Walking Horse (TWH) through the use of a three-dimensional (3-D) system. Four TWH were ridden through a six-camera motion analysis system at the W and RW. Reflective markers were used to track the movement of body segments and joint centers. Four specific gait events were used to calculate the temporal stride characteristics of W and RW. From these many other gait characteristics were calculated such as stride length and overstride. Joint angles of the lower leg were also characterized for each gait. Hind stance duration, advance placement, and advance lift off (all expressed as a percentage of total stride time) were similar between W and RW. At the carpal joint, the relative angles that differed between W and RW at the gait events are the same angles that are strongly correlated to stride length, overstride and advance placement. Velocity-independent characteristics were observed: hind stance duration as a percentage of total stride time, advance placement as a percent of total stride time, and advance lift off as a percentage of total stride time. Use of velocity-independent variables may make comparisons of gaits among horses possible even when the velocity among the horses is significantly different or cannot be controlled. Adaptation of 3-D kinematic analysis techniques will enhance our current understanding of equine locomotion and aid in the diagnosis and treatment of abnormal gait