Effect of different head-neck positions on physical and psychological stress parameters in the ridden horse.
Authors: Zebisch A, May A, Reese S, Gehlen H
Journal: Journal of animal physiology and animal nutrition
Summary
Zebisch and colleagues investigated whether different ridden head-neck positions affect equine physiology and behaviour, measuring heart rate, heart rate variability (HRV) and blood cortisol in 18 horses at rest, during working posture, and during hyperflexion. Whilst resting heart rate and HRV parameters showed no significant differences between the two ridden positions (working posture HR 105±22/min versus hyperflexion HR 110±18/min), blood cortisol concentrations increased significantly under hyperflexion (158±60 nm to 176±64 nm; p=0.01), indicating a physiological stress response despite comparable autonomic nervous system activity. Subjective assessment by both riders and observers documented marked deterioration in rideability and behaviour during hyperflexion across all parameters measured. The elevation in circulating cortisol—a reliable marker of the stress axis—coupled with observable behavioural changes, suggests that hyperflexed positions trigger a genuine stress response in ridden horses, raising questions about their widespread adoption in training and competition despite their purported benefits. These findings warrant consideration by all equestrian professionals involved in training decisions, as maintaining a working head-neck position appears capable of delivering rideability gains without the physiological and behavioural costs associated with hyperflexion.
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Practical Takeaways
- •Hyperflexion positions, despite being popular in competition and training, provoke a physiological stress response detectable through elevated blood cortisol levels—discontinuing or minimizing this practice may improve horse welfare
- •Behavioral deterioration observed by both riders and observers during hyperflexion should alert practitioners that apparent 'obedience' in this position may reflect stress rather than improved training outcomes
- •A working head-neck position maintains comparable cardiac parameters to hyperflexion while avoiding the documented stress elevation, making it the safer biomechanical choice for ridden work
Key Findings
- •Blood cortisol levels significantly increased during hyperflexion (176 ± 64 nm) compared to working head-neck position (158 ± 60 nm, p = 0.01), indicating stress response
- •Heart rate and heart rate variability showed no significant differences between working position (HR 105 ± 22/min, LF/HF 3.89 ± 5.68) and hyperflexion (HR 110 ± 18, LF/HF 1.94 ± 2.21)
- •Rideability and behavioral parameters deteriorated significantly during hyperflexion compared to working head-neck position based on rider and observer evaluations
- •Hyperflexion induced measurable physical stress (elevated cortisol) and observable behavioral changes indicating compromised horse well-being