Do Muscle Activities of M. Splenius and M. Brachiocephalicus Decrease Because of Exercise-Induced Fatigue in Thoroughbred Horses?

The study explores if exercise-induced fatigue affects the muscle activities of the splenius and brachiocephalicus in Thoroughbred horses. The results indicate that these muscles’ activities can be associated with stride frequency and speed.

Objective of the Research

• The primary aim of this study was to quantify the fatigue-induced changes in the electromyographic readings of the head, neck, and shoulder joint muscles in thoroughbred horses caused by intense running exercise.

Methodology

• The researchers studied nine healthy Thoroughbred horses to collect data for the research.
• Surface electromyographic recordings of the splenius, brachiocephalicus, infraspinatus, and deltoid muscles were performed on these horses to record their muscle activities during exercise.
• The exercises involved the horses galloping on a treadmill inclined to 3% at a constant speed to induce fatigue after around five minutes. They also trotted at a slow pace before and after the intense exercise session.
• The researchers calculated the stride frequency, integrated electromyographic values for a stride, and median frequency of the muscle discharge every thirty seconds during the exercise.

Results and Observations

• The stride frequency significantly decreased by the end of the galloping exercise, indicating fatigue.
• No notable changes in stride frequency were observed while trotting.
• The integrated electromyographic values of the splenius and brachiocephalicus muscles in both leading and trailing limbs decreased significantly, pointing towards the decrease in their muscle activities with fatigue.
• There were no significant changes observed in the electromyographic values of the infraspinatus and deltoid muscles, implying that these muscles did not fatigue as much at either the gallop or trot speed.
• No changes were observed in the median frequency in any muscles due to fatigue.

Conclusion

• The findings of the research suggest that fatigue from exercise can decrease muscle activities in the splenius and brachiocephalicus muscles of Thoroughbred horses. These changes were associated with a decrease in stride frequency and speed.