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Overground and aqua treadmills are becoming an increasingly popular means of exercising horses in both professional and amateur yards. Are there real benefits to be gained from incorporating treadmill use into your training programme, or is this just another novel and expensive gadget?

Low-speed overground treadmills offer ease of use over hand-walking or automated horse-walkers, for warm-up and warm-down regimes, conditioning and controlled rehabilitation programmes.

They take up less room than a conventional horse-walker, with the advantage that a horse can move in a straight line and on an even surface. A treadmill is the ultimate in controlled exercise, where you determine the speed, inclination and duration of the work your horse completes.

Hand-walking, so often prescribed by vets when horses are recovering from musculoskeletal injuries, can be problematic.

Horses on box rest are often difficult to control when walked in hand and there can be concern for handler safety. The only variable that can be controlled is the duration of exercise, which may be increased on a weekly basis.

Horse owners often find this walking exercise boring or fail to appreciate its importance, so sessions are often rushed or missed altogether.

Treadmill exercise offers several advantages: exercise duration and difficulty can be increased in exact increments, on equal footing, with or without a gradient or water resistance. Importantly, owners are more likely to follow a specific exercise plan when they don’t have to walk with the horse themselves.

There are potential disadvantages, however. In humans, high levels of treadmill use have been associated with a loss of agility — in that the even surface fails to mimic real-life conditions, where the body must continually adapt to ever-changing terrain. Fewer muscles are used while training on a treadmill when compared to running outdoors, and this may be the same for horses.

Human treadmill runners are at a lower risk of developing tibial stress fractures than overground runners, but are less likely to achieve tibial bone strengthening. So, although it may put less strain on your horse’s limbs, treadmill work may not adequately replace the conditioning required to strengthen his bones and is not an alternative to hacking and roadwork as a form of exercise.

In addition, long periods of time on the treadmill may be incredibly boring for your horse. An important element of training and exercising is the development of mental as well as physical soundness. Relentless treadmill work is unlikely to stimulate your horse’s inquisitive nature.

Moving up a gear

High-speed treadmills are sometimes used to supplement track exercise in the training of young thoroughbreds, allowing the horse to move at high speeds without the added weight of a rider. Research has suggested that with the addition of intermittent high-intensity treadmill exercise, an equine athlete may be able to achieve higher aerobic fitness during training without subjecting his musculoskeletal system to increased loading with rider weight.

Most horses adapt quickly to the system. Accidents can happen, however, so a horse should never be left on a treadmill unsupervised. The majority of high-speed systems are used exclusively with a harness and under the continual supervision of fully trained personnel. All units have emergency stop systems should the horse stumble or fall.

A cooling fan should be placed in front of the horse during high-intensity exercise, as he will not benefit from the cooling airflow usually created at higher speeds on land.

Aqua or water treadmills, initially developed specifically with post-injury rehabilitation in mind, are becoming increasingly popular for conditioning.

Despite the benefits, research has shown that eight weeks of conventional or underwater treadmill training resulted in only minor changes in type one muscle fibre sizes, with no effect on muscle metabolic or heart rate responses evident during standardised exercise tests. Following rehabilitation involving underwater treadmills, it is recommended that horses are trained at progressive speeds when ridden to develop the required fitness for subsequent speed work.

The workload on an aqua treadmill is a function of water level height and treadmill speed. Increasing the water height has a direct effect on resistance and postural sway (deviation from the centre of gravity). At walk, water height increases appear to have a greater impact on exercise intensity than an increase in belt speed. This can be useful in some injuries where higher speed may exacerbate the problem due to continued concussive forces on the limbs.

Research has shown that horses with carpal (knee) osteoarthritis undergoing water treadmill exercise had increased postural stability compared to those exercised on a normal overground treadmill. This means that arthritic horses could benefit from regular water treadmill use.

Walking in high water causes cranial thoracic (neck and back) extension and thoracolumbar (mid-back) flexion when compared to walking in water at hoof depth. At increasing water depths, there are significant increases in pelvic flexion and rotation of the spine. At the highest water levels (to the shoulder), there is reduced lateral bending of the spine.

Interestingly, after 10 days of this exercise, horses exhibited increased lateral bending. This postural change means that water height can be altered to target certain muscle groups when designing rehabilitation programmes for horses with back or hindlimb issues.

Making strides

Research on the effects of treadmill gradient has shown that muscle activity is triggered to a greater extent by an incline than a decline, and that greater increases are seen in hindlimb muscle activity when compared to forelimb. Despite this, different gradients do not seem to affect stride, with identical frequency and stride length seen in horses exercising uphill, downhill and on the level.

Oxygen consumption, carbon dioxide production and cardiac output are all increased with gradient increase, however, and reduced with downhill locomotion. Greater aerobic effort is therefore required when going uphill, and horses recovering from certain hindlimb injuries may benefit from not walking on an uphill gradient in the initial stages of recovery.

Despite an increase in published studies, there is relatively little scientific data recording exactly how aqua treadmills affect horse fitness. The research that does exist does not support specific exercise intensity or duration of training.

It must also be remembered that horses on treadmills are, to a point, forced to keep moving. They may be pushed closer to fatigue if programmes are not designed specifically for the individual and adapted regularly for fitness levels.

Ref Horse & Hound; 7 June 2018