Over 30 equine, veterinary, and footing specialists from three continents gathered at a special two-day equine surfaces forum held at FEI headquarters in Lausanne, Switzerland, in July. Experts from Belgium, Canada, Germany, Italy, Malaysia, Netherlands, Switzerland, the UK, and the US discussed standards for arena surfaces in jumping and its effects on the orthopaedic health of sport horses. Six years of FEI-funded research was presented at the forum, which concluded that the next stage towards the provision of consistently good surfaces at major events is the creation of a surfaces standard for the industry. This will be “a major step forward,” said Dr Lars Roepstorff, co-author of the Equine Surfaces White Paper, which was published by the FEI in 2014 and is the result of a four-year collaboration between eight equine experts from six universities, three equine and racing-specific research centres, and two horse charities.
A consensus emerged at the forum that procedures regarding three components – the correct materials and design, proper installation, and appropriate maintenance – will evolve into standards that can support manufacturers, educate show organizers, and protect horses and riders.
WHY FOOTING MATTERS
While a horse’s soundness and performance is intrinsically connected to a number of factors including age, genetics, training, condition, nutrition, shoeing and even rider position, the surfaces on which they ride is one area that can be controlled. A surface that is consistent, offers sufficient support to prevent injury, and makes optimal performance possible is essential. Research has documented that some surfaces are a risk factor for injury, but rider decisions can also influence the outcome. Case in point: the 2004 Olympic Games in Athens, where three jumpers sustained injuries attributed to the interaction between the surface and the caulks they were wearing.
MATERIAL AND DESIGN
Research has found that the performance of arena surfaces is characterized by the impact firmness, cushioning, responsiveness, grip, uniformity, and consistency over time. These qualities were explained in “rider terms”:
Impact firmness: The shock experienced by the horse and rider when the hoof contacts the surface.
Cushioning: How much a surface is supportive compared to how much it gives when riding on it.
Responsiveness: How active or springy the surface feels to the rider.
Grip: How much the horses’ foot slides during landing, turning, and pushing off.
Uniformity: How regular the surface feels when the horse moves across it.
Consistency over time: How much the surface changes with time and use.
The paper noted that in recent years there has been an increasing trend towards the use of artificial and synthetic surfaces rather than grass in competition arenas. Climate, year-round use, ease of maintenance, and more readily-available surfaces composed of silica sand and other materials due to an increase in the number of suppliers are all factors in this shift.
Dressage riders in the UK, for instance, favour sand-and-rubber, sand, woodchip, and sand-and-polyvinylchloride (PVC), with additives including strips of rubber, cloth, or felt. A polymer or wax coating is applied as a binder between the particles. Rubber and woodchip-based surfaces are usually cheaper to buy than premium sand-based surfaces. The rubber source material is usually either new rubber or ‘alternative’ rubber such as shredded carpet backing, processed tires, or belting. Rubber surfaces are effective in reducing the compaction of a sand or woodchip surface, although injury risk due to a lack of consistency and slippage may increase on woodchip-and-rubber surfaces if routine maintenance is ignored. The rate of degradation should also be monitored and materials refreshed as needed.
Very fine silica sand with up to 15% clay or silt content can provide a firm surface. Wax-coated sub-rounded sand with high quartz content is used to ensure durability and maintain vertical drainage. The addition of polymer or natural fibres and rubber particles adds elasticity during impact and reduces compaction. The use of fibres in sand-based surfaces appears to have many advantages, such as increased stability and drainage; however, high-quality fibres that are dust-free are expensive.
Wax-coated sand and fibre surfaces allow for long-term performance under a variety of conditions, but this comes at a premium. Compared to sand and woodchip surfaces, the incidence of lameness and injuries is reduced, supported by data from a racetrack which showed a significant reduction in impact shock-related variables on a waxed surface during trotting compared to a crushed sand track.
Many top venues such as Spruce Meadows, Aachen, and Hickstead opt for grass surfaces, which provide the horse with a more ‘natural’ footing. The functional properties are highly dependent on the quality of the root structure and the moisture content, and judicious maintenance is necessary to avoid compaction, which increases density and hardness. Poor-quality or overly-wet turf can lack ‘shear resistance’ (resistance of the surface to penetration by the hoof) and necessitate the use of shoe studs.
A uniform, level base and adequate drainage are essential to arena construction. Perforated pipes dug deep into the ground are often used, with screened limestone (preferred), crushed concrete, or porous asphalt traditionally applied above. In areas with low rainfall a clay base can be used. Woodchip or rubber beneath the top surface can also provide additional shock absorption.
Adequate drainage must be installed to ensure the surface recovers quickly from rainfall, but a surface that is too permeable will not be able to retain moisture during dry spells. Specialised drainage systems such as Equaflow™ and Ebb and Flow allow drained water to be reapplied to the surface via a storage tank and automatic pump; the Equaflow™ system was used under the arena footing at the 2012 Olympic Games in London.
Surface maintenance involves watering, harrowing, levelling, rolling and/or grading, which will reduce compaction and improve or maintain consistency around the arena. Uneven surfaces, varying moisture contents, and compaction are associated with a higher risk of injury to horses.
Emerging evidence suggests that horses change their gait patterns based on even minor changes in surface preparation; therefore, regularly altering surface preparation can stimulate different gait patterns which can be beneficial to training and conditioning. Older horses or those with chronic conditions may benefit from only exercising on surfaces prepared to limit the development of further degenerative changes.
The paper concluded that more research is needed and should focus on standardizing mechanical measurement techniques, in harmony with bio-mechanical feedback from the horse, to capture the data needed to identify injury risks and incorporate further improvements.