Distal hindlimb kinematics of galloping Thoroughbred racehorses on dirt and synthetic racetrack surfaces.

The research investigates the impact of different racetrack surfaces – dirt and synthetic – on the hindlimb and hoof movements of Thoroughbred racehorses during high-speed galloping.

Research Objective

• The aim of this study was to compare the distal hindlimb and hoof kinematics during stance (the phase of a stride in which the foot remains in contact with the ground) of galloping horses on dirt versus synthetic racetrack surfaces. This analysis can further our understanding of how different racetrack surfaces influence horse motion and potentially influence injury risk.

Methodology

• The researchers conducted a two-dimensional kinematic video analysis of five Thoroughbred horses galloping unrestrained (breezing) at high speeds (12-17 m/s) on dirt and synthetic racetracks.
• Kinematic markers were applied to the left hindlimb of the horses and recorded at a frequency of 500 Hz.
• The team analyzed position, velocity, and acceleration of joint angles and hoof movement in the sagittal plane (the vertical plane which divides the body into left and right).
• To compare the differences on both surfaces, peak translational (linear motion along a straight path) and angular kinematic values were studied using statistical models.

Results

• Several key differences were observed in hindlimb and hoof motion on the two track surfaces. Angles at the fetlock (joint analogous to the human wrist, located between hoof and shank) were greater and occurred earlier during stance on the dirt surface than on the synthetic surface.
• A larger horizontal displacement of the horse’s heel during sliding was also seen on the dirt surface.

Conclusions

• The research concludes that high-speed galloping on a dirt surface causes greater hindlimb fetlock hyperextension (increased bending beyond the normal range) and horizontal hoof slide than on a synthetic surface. Such variation may impart different strain patterns on fetlock support structures, potentially increasing injury risk.
• By reducing fetlock hyperextension and its associated strains, synthetic race surfaces may help mitigate the risk of injury to hindlimb fetlock structures.
• Differences in hoof slide on the different surfaces could also contribute to the observed differences in distal hindlimb kinematics between track surfaces. Such findings could influence racehorse training regimens, track material selection, and injury prevention practices.