Kinematics and kinetics of the carpus.

The research article examines the movement and forces on the carpus (a joint in a horse’s leg) during the stance phase of trotting in Standardbred horses. It finds that the carpus experiences overextension and high loading, with the results suggesting these forces occur due to horizontal braking of the hoof and the activity of flexor tendons.

Research Methodology

• The research involved five Standardbred horses, made to trot on a treadmill at a speed of 8.9 m/s.
• Kinematics, the study of motion, was used to capture the movements of the horses via filming.
• The hoof reaction forces (HRF), which are the forces exerted by the hoofs on the ground, were recorded simultaneously.

Research Findings and Analysis

• During the stance phase, the carpus was found to overextend at two stages – rapidly at the beginning and once more following the first overextension.
• The maximal overextension was noted to coincide slightly before the second minimum of the braking horizontal HRF.
• The metacarpal and antebrachial segments of the horse’s leg also displayed counter-clockwise rotation for most of the stance phase.
• These segments’ angular velocities showed concurrency in their absolute and local extremes.
• The moment of force about the carpus primarily exhibited extension, except for a brief period of flexion near the end of the stance phase.

Interpretation and Conclusion

• The study suggests that the overextension of the carpus results from the horizontal braking of the hoof, which leads to impulsive loading.
• It further proposes that the second overextension phase may be connected to the tension or active role of the flexor tendons in the horse’s distal limb (the lower part of the limb).
• Thus, the carpus undergoes rapid and high loading, both in longitudinal and transversal directions, and experiences large moments and forces.
• This information could provide insights into equine biomechanics, potentially informing improved training techniques and joint injury prevention strategies.