The effect of three different head-neck positions on the average EMG activity of three important neck muscles in the horse.

The research paper investigates how different head-neck positions affect the muscle activity in horses. It finds varying levels of electromyographic activity in three essential neck muscles in a horse according to the different positions – free, gathered (head higher, neck more flexed), and hyperflexed.

Research Purpose and Methodology

• The paper aimed to understand the muscular activity of horses while changing their head-neck positions (HNPs). This knowledge is crucial for making reasonable judgements on HNPs and their implications on the horses’ health and performance.
• The study utilized surface electromyography to record the electrical activities of three major neck muscles of a horse – m. splenius, brachiocephalicus, and trapezius.
• Five horses were included in the study. They were examined in three different gaits on both hands, both with and without a rider.
• The recordings were made in three different HNPs – a ‘free’ position, a ‘gathered’ position, and a ‘hyperflexed’ position.
• The averages of ten consecutive gait cycles in each HNP were evaluated and compared using standard statistical methods.

Research Findings

• The research found no significant difference in muscle activity between the ridden and unridden horses.
• In the hyperflexed position, the m. brachiocephalicus was significantly more active than in the free and gathered positions.
• The m. splenius was less active in the hyperflexed position than in the free position, which had the highest activity.
• The muscle activity in the free and gathered positions significantly deviated during walking.
• The m. trapezius was least active in the hyperflexed posture during walking compared to the free and gathered positions.
• The pattern was the same during trotting; however, there was no significant difference between the gathered and hyperflexed positions.
• In cantering, the m. trapezius showed no palpable differences during different HNPs.

Conclusions

• The research concludes that when the horse’s noseline is in front of the vertical, the muscles of the topline (m. splenius, m. trapezius) are stimulated and trained.
• However, when in a hyperflexed position, a major muscle of the lower topline (m. brachiocephalicus) gets activated and trained.
• The findings give insight into how riders can optimize their handling depending on the desired muscular engagement of their horses.