The effect of three different head-neck positions on the average EMG activity of three important neck muscles in the horse.
Authors: Kienapfel K
Journal: Journal of animal physiology and animal nutrition
Summary
# Editorial Summary Kienapfel's 2015 investigation into cervical muscle recruitment across different head–neck positions provides objective evidence for understanding how ridden and groundwork postures influence the horse's muscular development. Using surface electromyography on five horses, the researcher recorded activity in the splenius, brachiocephalicus, and trapezius muscles whilst performing walk, trot, and canter in three distinct positions: free (natural), gathered (head higher, neck flexed, noseline in front of vertical), and hyperflexed configurations. The findings revealed distinct neuromuscular signatures for each position—the splenius and trapezius showed greatest activation in the free position, moderate activity in the gathered position, and significantly reduced activation in hyperflexion; conversely, the brachiocephalicus demonstrated substantially higher recruitment only in hyperflexion (p < 0.01), with no meaningful difference between free and gathered positions. Notably, rider presence produced no measurable effect on any muscle activity pattern, and gait-specific responses occurred, particularly at walk where positional differences were most pronounced. For practitioners, these findings suggest that gathered postures with the noseline in front of the vertical preferentially engage topline musculature (splenius and trapezius), making them appropriate for developing postural strength, whereas hyperflexed positions preferentially recruit the ventral cervical structures and should be employed strategically if targeting lower neck musculature development.
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Practical Takeaways
- •Free and gathered head-neck positions (noseline in front of vertical) preferentially activate topline muscles (splenius, trapezius), making them more suitable for training the dorsal neck muscles
- •Hyperflexed positioning preferentially activates the brachiocephalicus (lower neck muscle) while reducing topline muscle activity, representing a different training stimulus with distinct muscular engagement patterns
- •Rider presence does not meaningfully alter neck muscle activation patterns, suggesting that the head-neck position itself—not the weight of a rider—is the primary determinant of muscle activity
Key Findings
- •The m. brachiocephalicus was significantly more active (p < 0.01) in hyperflexed position compared to gathered and free positions across all gaits
- •The m. splenius showed highest activity in free position and significantly less activity (p < 0.02) in hyperflexed position
- •The m. trapezius was significantly less active in hyperflexed posture during walk (p < 0.01) and trot, with strongest activity in free position
- •No significant difference in muscle activity was detected between ridden and unridden horses in any position or gait