Ridden water submersion training (RWST) provides moderate sub-maximal intensity exercise for elite international eventing horses whilst restricting temperature increases in the lower limbs commonly associated with tendon rupture, researchers report.
Superficial digital flexor tendon injuries are the most common musculoskeletal injury reported in jumping disciplines.
Water treadmills are used for rehabilitation purposes, but have also recently been employed for conditioning unfit competition horses returning to training.
Swimming is also used in some training programmes to mimick workload while minimising strain on the limbs by submerging a horse in a swimming pool and allowing the animal to swim at its preferred speed.
RWST is a ridden form of conditioning that involves submerging the horse to its sternum and trotting for set intervals at a pace controlled by the rider. It can be carried out at the beach or in an artificial lake.
The technique has been employed by a small number of trainers in a bid to reduce incidences of injuries in elite eventing horses.
Claire O’Brien and Josephine Pegg, writing in the journal Animals, said the conditioning technique is used by a small number of trainers to increase cardiovascular fitness whilst potentially minimising tendon temperature increases, typically reported during traditional conditioning sessions.
The study employed 15 clinically sound international-standard eventing horses from a stable in Belgium, monitored across five training sessions. Base temperatures were recorded in the horses’ stables before work began.
All horses underwent the same out-of-water warm-up routine, involving walking, trotting and cantering on both flat undulating terrain. They then entered the water and were trotted for intervals, with 1 minute walk breaks on land between each interval.
Their heart rate and speed were monitored during the conditioning work. Skin temperature of both the left and right front legs were monitored at various points using an infrared thermal imaging camera as a pseudo-temperature for tendon temperature.
The heart rate predictably increased during training, but remained within the parameters for increased aerobic stamina.
The lower limb temperatures decreased significantly after the warm-up phase — that is, once the submersion training began.
O’Brien and Pegg said they were limited to using non-invasive measures available to monitor the physiological effects of the submersion training and could not carry out evaluations of fitness levels under maximal conditions before starting data collection.
As such, they used proxy values in order to estimate fitness levels in horses, and therefore, cannot comment objectively on whether this level of work resulted in changes to fitness levels.
They said further research is required to properly establish the long-term effects of incorporating this form of exercise into a training programme, as well as various factors that can affect physiological responses.
They said the preliminary results suggest that RWST may be a useful adjunct to current conditioning methods when training horses for competition, especially with regard to disciplines that involve a high risk of lower limb injury.
The results indicate that RWST used may prevent an increase of tendon temperature commonly associated with increased cardiovascular demands during training on land.
Combining the use of infrared thermography with other methods such as ultrasound tissue characterisation may also increase the reliability of such measurements in future studies.
The mechanisms that prevent an increase in distal limb temperature during RWST require further elucidation in relation to the reduced loading placed upon the lower limb, they said.
Water treadmill studies may be able to further clarify how different combinations of water height and temperature affect lower limb temperatures after exercise.
Further investigations on the long-term effects of this particular water-based training method on range of motion, stride length, and stride frequency would also be beneficial due to alterations in stride patterns observed during training, they said.
The authors noted that horses competing at elite levels of eventing represent only a small percentage of the total performance horse population.
They concluded that further investigation of the technique is warranted to establish a more robust understanding of its effects on both elite and non-elite performance horses, and those competing in other disciplines. Such research could potentially help pinpoint at what stage of the fitness programme it could be incorporated.
O’Brien is with the Department of Biological Sciences at the University of Portsmouth in England; Pegg is with the Higher Education Department at the University Centre Sparsholt in Winchester, England.
O’Brien, C.; Pegg, J. A Preliminary Investigation into Ridden Water Submersion Training as an Adjunct to Current Condition Training Protocols in Performance Horses. Animals 2021, 11, 2629. https://doi.org/10.3390/ani11092629