Arena Maintenance's Effects on Horse Movement

Arena Maintenance's Effects on Horse Movement

Arena maintenance changes the surface's properties, which in turn alters horses' movement patterns.

Photo: David Young/The Horse

Editor's Note: This article is part of's ongoing coverage of topics presented at the British Equine Veterinary Association's 51st annual Congress, held Sept. 12-15 in Birmingham, U.K.

In recent years, the sport horse industry has seen an increase in artificial arena surfaces used for both training and for competition. While previous studies have shown that some of these surfaces' features can increase a horse's risk of injury, scientists have yet to determine the mechanism by which these injuries occur.

A team of researchers from the Animal Health Trust (AHT), in Newmarket, England; the College of West Anglia, in Cambridge, England; and the Swedish University of Agricultural Sciences recently compared the effects of arena maintenance on mechanical properties of two arena surface types. Vicki Walker, MSc, from the AHT, presented the study findings on behalf of the group (including Carolyne Tranquille, BSc, and Rachel Murray, MA, VetMB, MS, PhD, MRCVS, Dipl. ACVS, ECVS, both from the AHT) at the British Equine Veterinary Association's 51st annual Congress, held Sept. 12-15, in Birmingham.

"Epidemiological data has shown that regular (working surface) maintenance has been found to decrease the risk of injury," said Walker.

For instance, researchers have determined superficial harrowing decreases compaction and resulting hardness of dirt, sand, and woodchip surfaces, she explained. It also increases the evenness and uniformity of dirt and woodchip surfaces. And watering sand-based surfaces has been shown to increase their firmness, providing greater stability for the horse.

However, she noted that researchers completed these studies on racing and trotting tracks, so to date there is no information on maintenance's effects on the artificial surfaces used by sport horses.

"To address this, the aim of this study was to investigate the effects of superficial harrowing on a waxed sand and rubber surface and the effects of watering on a waxed sand and fiber surface in relation to mechanical surface characteristics and the kinematics (measurement of body motion) of the working trot," said Walker. "We hypothesized that arena maintenance would have a significant effect on the mechanical characteristics of the surface; that uniformity of the surface would be improved after maintenance; and that the kinematics of the horse would change between pre- and post-maintenance conditions."

Study Methods

In the study, the research team evaluated two arenas at one equestrian center. One was an outdoor arena with a waxed sand and rubber surface, which they tested pre- and post-superficial harrowing. The other was an indoor arena with a waxed sand and fiber mix surface, which they tested watered (using a sprinkler system for 20 minutes) and unwatered.

The team then collected kinematic data from eight general purpose riding horses all ridden by the same rider on both surfaces. They evaluated the working trot using high-speed motion capture at 250 frames per second, looking at two sets of four trot strides from separate locations in the arena. "We controlled the speed of the horses to 3.5 meters per second, and we put anatomical markers on the left fore and hind limbs only," said Walker.

To measure the arena surface characteristics, the team used a dual-axis synthetic-hoof drop hammer, which provided them with information about the surface's firmness, grip, and elasticity (which relates to energy return--the more elasticity a surface has, the less effort the horse needs to exert). To measure the surface's uniformity, they performed three "drops" at 10 locations across the arena and compared this data pre- and post-maintenance.


"After harrowing (the waxed sand and rubber surface) there was a significant increase in hind limb hoof slide, a significant increase in fore- and hind limb fetlock extension, and a significant increase in tarsal (hock) extension angle at the onset of the liftoff stage of stance (as the horse was about to lift the foot from ground contact)," Walker explained.

The arena itself became less firm and elastic, and it offered more grip.

"After watering the sand and fiber surface, there was significant increase in hind limb duty factor (when the foot is on the ground), and a significant decrease in mid stance tarsal flexion," she said. "There were no significant differences observed in any other kinematic variables."

This arena exhibited increased firmness, grip, and elasticity. Walker noted that watering also made the surface more uniform, with the exception of one region where water collected during the process.


Based on these results and observations, the team concluded that superficial harrowing did not improve the waxed sand and rubber surface's uniformity, whereas watering did improve the waxed sand and fiber surface's uniformity.

"In terms of kinematics, the horses showed an increase in joint extension when the elasticity of the surface decreased and a decrease in joint flexion when the elasticity of the surface increased," said Walker. "This is likely to be a combined mechanical and proprioceptive (physical awareness of limbs and their placement) response to the alteration in energy required to maintain the same trotting speed. Effectively, the horse needs to preload the limb less in the stance phase when the elasticity of the surface is higher."

The researchers recorded similar findings in relation to firmness: The horses showed an increase in joint extension when surface firmness decreased and a decrease in joint flexion when the firmness increased. "This could be a proprioceptive response inducing an anticipatory muscle contraction aiming to minimize the impact to the limb," Walker explained.

All of these kinematic changes indicate the need for uniformity across an arena surface to prevent injury. For instance, said Walker, if there's large variation across a surface, the horse is likely changing his gait frequently in response. This could cause the horse to fatigue or lose his balance--both of which can negatively affect performance and lead to injury.

"In summary, arena maintenance changes the mechanical properties of the arena surface, and this appears to alter the movement pattern of the horse," said Walker. "This highlights the need for uniformity across the arena, which was improved by watering on the sand and fiber surface, but not with superficial harrowing of the sand and rubber surface. This suggests that deeper harrowing might be beneficial for (the latter) surface."

Walker did note that the study was limited by using only two surfaces and following the equestrian center's standard maintenance procedures. In reality, the size, shape, and components of harrowing equipment horse and facility owners use vary widely.

"It would be beneficial to study the effects of different maintenance equipment, including different types and subtypes and also the effect of the vehicle towing them," she said. "And it would also be interesting to investigate how different surface types respond to these different techniques."

About the Author

Alexandra Beckstett, The Horse Managing Editor

Alexandra Beckstett, Managing Editor of The Horse and a native of Houston, Texas, is a lifelong horse owner who has shown successfully on the national hunter/jumper circuit and dabbled in hunter breeding. After graduating from Duke University, she joined Blood-Horse Publications as Assistant Editor of its book division, Eclipse Press, before joining The Horse.

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