When it comes to swimming horses, it seems we’re awash with anecdote and opinion rather than hard evidence. Working with the science available, however, experts agree swimming can play a part in conditioning and rehabilitation.
“The main perceived advantage is minimal musculoskeletal stress,” says Patrick Pollock FRCVS. “Objective data on this is noticeably lacking, with no evidence to support the claim that horses which are regularly swum have greater cardiovascular fitness.
“However, there is evidence that concentrations of muscle enzymes may be a little lower for horses in training that regularly swim, versus those with no access to a pool, suggesting that there is less muscle damage and inflammation than with high-intensity, land-based exercise.
“Results of studies on the equine airway during swimming suggest that horses can be put under significant stress,” explains Patrick, referring to the considerable energy required for a horse to propel himself through the water.
Dr Susanna Ballinger MRCVS believes swimming can enhance a training programme.
“Swimming helps maintain aerobic fitness, reducing the impact of stress-loading of limbs while increasing muscle strength and range of motion of joints,” she explains. “Water provides buoyancy and resistance, which can aid muscular, cardiovascular and respiratory conditioning.
“In racing and competition horses, swimming may complement regular training and, without the concussive forces present with repeated ridden exercise, may be particularly appropriate with an underlying injury such as subchondral bone pain, certain osteoarthritis presentations or a tendon injury.
“However, swimming does not improve bone density, or conditioning or strengthening of tendons, so should only form part of a varied training regime”
Total immersion
“In terms of rehabilitation of soft tissue injuries, there are major advantages of working a horse in a low-weight environment,” says Patrick.
But unlike other forms of hydrotherapy, such as static spas or water treadmills, swimming involves immersion and exertion, which rules out certain cases.
“While swimming can be valuable during rehab for all types of horse and pony, in all disciplines, it is not suitable for every injury or where there are skin sores or open wounds,” explains Susanna.
“Horses are not natural swimmers and in water adopt a posture which is different to that for ground movement; they extend the neck and back and rotate the pelvis, while using the forelimbs to maintain balance and the hindlimbs for propulsion. It’s not usually suitable for animals exhibiting neck or back pain, or upper limb and pelvic lameness.
“The respiratory effort required makes swimming inappropriate if there are respiratory function concerns, or a history of bleeding from the lungs at exercise,” she adds. “It should also be used with caution with any history of exertional rhabdomyolysis (tying up) — a horse who ties up may be reluctant to move. If this happens while he is swimming, there is a risk of drowning if he cannot be removed quickly from the water.
“However, regular, low-intensity swimming can aid weight loss in the obese horse, and will benefit those with insulin dysregulation such as equine metabolic syndrome (EMS).”
New evidence
Dr Florent David, of the Equine Medical Centre based at the Al Shaqab Equestrian Complex in Doha, Qatar, uses the extensive facilities available for rehabilitation of horses with various medical and surgical conditions. He also believes that swimming has a place in diversifying a horse’s training programme.
Florent and Dr Renaud Leguillette of the University of Calgary, Canada, are conducting ongoing research into the effects of the activity.
“We’re still looking at the data but already we have some interesting results,” he says of the as-yet unpublished findings. “We know that breathing patterns are very different. A horse going into water typically enters a phase of ‘apnoea’ — similar to the diving reflex in mammals — where he holds his breath. In our swimming corridor, which allows almost 70 metres of active swimming, horses were holding their breath for nearly 17 seconds.
“We also wanted to find out whether the exercise is aerobic [with oxygen] or anaerobic [without],” he adds. “Most horses show a short inspiration of air followed by an explosive expiration; this is probably because the nose is so close to the water and, being an obligate nasal breather, the horse has no means of breathing through his mouth and absolutely needs to prevent water from entering his nose.
“A research group in Australia had already looked at the function of the nasopharynx when horses swim, using an endoscope,” he adds. “It would be interesting to see if swimming could be used to correct the muscling of the pharynx, perhaps using horses with swallowing issues.”
Florent explains that little is known about VO2 max (maximum oxygen uptake), when a horse is in water — for example, how much the heart rate climbs and any changes in terms of cardiac electrical activity. The researchers fitted the horses with VO2 masks to measure maximum oxygen consumption during swimming.
“Surprisingly, the swimming effort was not as high intensity as thought before. For the horses used (elite endurance athletes and regular swimmers), the data showed that it was totally aerobic and low intensity.”
Swimming style
Using surface and underwater cameras, along with markers on the horses, the team assessed the kinematics (properties) of the equine swimming motion.
“We knew that horses swim with movement similar to what standardbred pacers in harness racing show, but we examined the amplitude [extent] of the movement and the use of joints and muscle groups,” says Florent.
“Some horses seem to experience back pain when they swim, so we explored whether the back is under more pressure in the pool. Some horses swim with a high head carriage, forcing the back into a full extension that can aggravate kissing spine problems, but I’m not sure we can say that swimming induces back pain. From observation, this depends on individual swimming style. There appears to be a huge variation in how horses tolerate this exercise.”
Additional findings may shed further light on swimming for rehabilitation.
“For horses with EMS and laminitis, nothing is better in terms of burning energy,” adds Florent, explaining that 10 minutes of swimming may be equivalent to two hours of walking on land. “As long as the laminitis sufferer is over the acute phase, the activity is not stressful on his feet.
“I also have a feeling that swimming has a beneficial effect on bone healing,” he says. “After fracture repair, we put most horses in water as soon as the wound has healed and the stitches are out. With most fractures repaired surgically, the fracture line disappears more quickly on the radiographs with swimming.
“I don’t yet know if this is due to an overall reduction in bone density or a true acceleration of the healing process, but something definitely happens.”
More questions than answers, maybe, but Florent sees there is great potential. To ensure swimming is safe and beneficial, work with your vet and choose a well-established pool with experienced operators.
‘He developed so much stamina’
When driving pony Penwarne Banjo Boy sustained a muscular niggle last summer that required a short period of rest, Chris Ainscough was obviously keen that his 13.1hh gelding maintained his cardiovascular fitness.
“The injury was minor, but it coincided with our individual selection for the British team at the FEI world driving championships for ponies last September,” said Chris, who sent “Joe” to swim at Higher Spen Equine in Lancashire.
Over six weeks, the spotted pony built up to four sets of 10 laps of the 25-metre pool per session, totalling 1km of swimming each day.
“Joe became incredibly fit and developed so much stamina,” said Chris. “He always had a bit of a tummy but he shed around 20kg, without losing any of the topline muscle he needs to work in the correct, rounded outline for driving.
“We were delighted with his performance at the championships and decided to keep up the swimming at Higher Spen — Joe really took to it.”
Ref Horse & Hound; 20 February 2020
