Kinematics of the equine back and pelvis
Authors: WEEREN RENE VAN
Journal: The Athletic Horse
Summary
Back mobility represents a key welfare indicator in horses, yet veterinary assessment remains largely subjective during clinical examination. Van Weeren's 2014 investigation validated a practical field-based method using inertial measurement units (IMUs) positioned at the withers, eighteenth thoracic vertebra and pelvis to quantify thoracolumbar flexion and extension, benchmarking these measurements against motion capture technology across walk, trot and circular gallop. The IMU-derived method demonstrated remarkable accuracy, with mean biases of just 0.8° (±1.5°) for flexion and 0.8° (±1.4°) for extension across all gaits, proving statistically equivalent to the gold-standard MOCAP system. For practitioners, this represents a significant development: objective measurement of spinal mobility is now achievable in field settings without expensive laboratory infrastructure, potentially enabling more rigorous longitudinal monitoring of back function in training, rehabilitation and clinical cases. The practical value hinges on future research correlating these biomechanical values with recognised clinical signs of back dysfunction, which would establish threshold values for identifying genuine mobility deficits versus normal variation.
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Practical Takeaways
- •IMU devices can reliably quantify back flexion/extension in the field, providing objective data to supplement visual assessment during lameness exams
- •This technology could standardize back mobility evaluation across different clinicians and track changes over time in individual horses
- •Future validation work is needed to establish how IMU measurements correlate with clinical signs of back pain or dysfunction
Key Findings
- •IMU-based method for measuring back mobility showed mean bias of 0.8° (±1.5°) for flexion and 0.8° (±1.4°) for extension compared to motion capture gold standard
- •Method demonstrated similar accuracy to motion capture across all gaits (walk, trot, gallop)
- •IMU technology enables quantification of back mobility under field conditions without laboratory infrastructure