Locating Lameness

Can modern digital gait analysis systems rival a trained human eye? Dr Thomas Witte discusses their role in lameness detection

- Thomas Witte

WHEN I first started carrying out equine gait analysis during my veterinary degree, around 15 years ago, our techniques were still very much in their infancy.

The technology was cumbersome and so sensitive that only highly skilled technicians could get accurate results, and even then horses had to be measured in a controlled environment moving in a straight line through a predefined space. Force platforms, basically glorified high-precision weighing scales, were used to gauge the forces under a horse’s feet and infrared cameras and reflective markers attached to surface landmarks measured the resultant movement.

These techniques were similar to those used in filmmaking at that time. While the same technology still exists and has been incredibly fruitful in moving forward our understanding of equine locomotion and musculoskeletal pathology, this approach was never going to enable widespread measurement of large numbers of horses.

As with many areas, it was technological breakthroughs and spins-offs from other fields that allowed this work to advance. Inertial measurement units that calculate movement from acceleration are used in navigation systems. As the technology became smaller and cheaper, researchers started deploying inertial measurement for gait analysis.

Ultimately, the technology has become so small and lightweight that it is found in virtually every smartphone or smart watch, and offers a non-invasive way to measure movement under real-world conditions. We first used inertial sensors on galloping racehorses to measure energy efficiency and soon started to see applications in the measurement of movement symmetry and lameness detection.

MAKING STRIDES