Effect of Fatigue on Equine Metacarpophalangeal Joint Kinematics-A Single Horse Pilot Study.

This article reports a pilot study which aimed to investigate how fatigue affects the movement of a key joint in a horse leg, using a single horse and monitoring its gait as it was exercised to the point of exhaustion. It discovered variations in joint movement dynamics as fatigue set in.

Objective of the Study

• The researchers were interested in examining the effects of fatigue on the movement of the metacarpophalangeal joint (MCPJ) in a healthy Thoroughbred horse. MCPJ is a significant joint in the horse’s front leg, often subjected to high mechanical stresses during motion.

Methodology

• The study involved one horse running on a treadmill to the point of fatigue. The fatigue state was measured by heart rate exceeding 190 beats per minute and blood lactate levels above 10 mmol/L.
• The researchers employed a specialized technique known as electrogoniometry to closely monitor and record the angles of the horse’s MCPJ during both nonfatigued and fatigued states.

Results and Observations

• Using electrogoniometry, researchers noted consistent changes in the horse’s MCPJ movement as it progressed from a nonfatigued to a fatigued state. This included an increase in the mean MCPJ maximum extension angle, alterations to extension and flexion angular velocities, and modifications to stride duration and frequency.
• As the exercise duration and treadmill speed increased, there was an obvious transition from nonfatigued to fatigued states, as evidenced by rising heart rate and blood lactate levels.

Implications and Future Prospects

• This preliminary study enabled an initial comprehensive characterization of the dynamic relationship between fatigue and MCPJ movement in horses.
• The findings highlight a potential line of research that can improve our understanding of how exercise-related injuries in horse limbs can be mitigated among equine athletes.
• However, the researchers emphasize the need for larger-scale studies involving multiple subjects to further validate and build upon the findings of this pilot study.