The effect of treadmill speed and gradient on equine hindlimb muscle activity
Article first published online: 8 NOV 2010
© 2010 EVJ Ltd
Equine Veterinary Journal
Special Issue: Proceedings of the 8th International Conference on Equine Exercise Physiology
Volume 42, Issue Supplement s38, pages 412–416, November 2010
How to Cite
CROOK, T. C., WILSON, A. and HODSON-TOLE, E. (2010), The effect of treadmill speed and gradient on equine hindlimb muscle activity. Equine Veterinary Journal, 42: 412–416. doi: 10.1111/j.2042-3306.2010.00222.x
- Issue published online: 8 NOV 2010
- Article first published online: 8 NOV 2010
- [Paper received for publication 09.01.10; Accepted 21.06.10]
Reasons for performing study: Locomotion requires successful negotiation of different terrains, but we currently know little of how the musculoskeletal system adapts to cope with positive and negative slopes.
Objective: To compare the effects of treadmill speed and gradient on equine hindlimb muscle mean electromyographic (EMG) intensity.
Methods: Surface EMG recorded the activity of gluteus medius (GM), biceps femoris (BF), vastus lateralis (VL), gastrocnemius lateralis (GL) and extensor digitorum longus (EDL) in 6 horses at walk (1.4–1.6 m/s) and trot (2.6–3 m/s) on 3 different treadmill gradients (0, 10% and −10%). Significant differences in mean EMG intensity and kinematic data were determined using Friedman and Wilcoxon signed rank tests (P<0.05).
Results: Increasing velocity increased the mean EMG intensity of GM, BF and GL regardless of gradient. Treadmill incline increased the mean EMG intensity for all muscles at the walk and that of GM at trot. Treadmill decline reduced the mean EMG intensity of GM at both the walk and the trot and that of BF at the walk, but not the trot. The mean EMG intensity of EDL, VL and GL remained similar at both gaits when compared to the horizontal.
Conclusions: The hip retractors are the primary muscles responsible for powering equine locomotion in response to increasing workload.
Potential relevance: A better understanding of the effects of speed and gradient on the functional activity of the horses' locomotor muscles will enable the development of more effective training programmes pre- and post injury.