Comparison of VHS video recording system with apple Macintosh-based image analysis and modified CODA-3 systems in equine motion analysis

A VHS video--computer-based image analysis combination is described as a low sampling rate motion analysis system. Video recordings were taken indoor without any artificial illumination at 25 fps sampling rate. The horse studied was running on a high-speed treadmill and observed at 1.6, 4 and 7 m/s velocities at walk, trot and canter, respectively. Left forelimb and hindlimb were recorded separately from lateral view. For comparison, parallel CODA-3 recordings were taken at the same time from the same position. Joint angles were expressed and compared in angle-time diagrams. Sampling of both systems has been synchronised by a timer device at +/- 1/300 s error level. Results obtained with the two different recording systems were comparable in all joints measured with the exception of the fetlock. Inaccuracies in fetlock recordings are thought to be eliminated by measuring at controlled illumination. As a conclusion, the VHS-Macintosh setup appears to be promising as a simplified system for gait analysis.