A kinematic and strain gauge study of the reciprocal apparatus in the equine hind limb.

This research investigates the movement and strain of a particular muscle, the peroneus tertius, in the hind limb of horses. Using special measuring techniques, it was found that there was a consistency between the muscle strain derived from external measurements and those directly measured. However, accurate results required adjustments to account for skin movement and the strain did not go beyond 3% at both walking and trotting paces.

Research Methodology

The researchers used a blend of kinematic study and strain gauges to gather data. For the kinematic study:

• Five horses were selected for the study.
• An opto-electronic system, CODA-3, was used to track the kinematics of the equine hind limb during walking and trotting.
• The researchers focused on the peroneus tertius muscle, a completely tendinous muscle in the horse’s hind limb.

In addition to the kinematic study, the strain in the peroneus tertius muscle was recorded in real-time using implanted mercury-in-silastic strain gauges.

Data Analysis

• Using the raw kinematic data, the researchers calculated the origin-insertion length patterns of the peroneus tertius muscle
• They also estimated these patterns from data that were corrected for the error caused by skin displacement. This adjustment is crucial to obtaining accurate results as the movement of the skin can interfere with the measurements.
• Both datasets were compared with the directly measured strain from the strain gauges.

Findings

• The researchers found a substantial consistency between the strain patterns obtained from externally measured kinematic data and those directly measured from the strain gauges.
• However, it was revealed that accurate results could only be achieved by correcting for skin displacement.
• The strain levels did not exceed 3% irrespective of whether the horses were walking or trotting. This suggests that this muscle endures roughly the same level of strain irrespective of the pace of movement.

Implications

This study provides substantial insights into the biomechanics of horse movement, specifically in the hind limb. Understanding the strain on the peroneus tertius muscle, and the influence of skin displacement on accurate measurements, could be useful in diagnostics, preventive measures, and treatment of exercise-related injuries in horses.