4: Hydrotherapy



Hydrotherapy allows the animal to exercise in water. The properties of water can provide an ideal environment to assist weak animals to regain motor function, or in the more able animal water can be used to provide resistance and have a muscle-strengthening effect.

The aims of hydrotherapy

Maintain or improve joint ROM

When an animal is exercising in a water treadmill and lifts his limb to propel himself forwards the buoyancy effect of the water will further increase flexion of the limbs joints.

Improve muscle strengthening

The density and gravity of the animal in water and the resistance from the viscosity of the water molecules will provide the animal with an ideal environment in which to exercise and improve muscle strength. To progress the patient use less water so reducing the buoyancy effect of the water and focusing on strengthening as the animal navigates against the resistance provided by the water. Further resistance can be added by using water jets for the animal to work against.

Gait re-education

The water will provide support for animals with neurological conditions and balance deficits. If these animals are recovering from spinal surgery they may need to re-learn motor movement patterns. A water treadmill is an ideal environment as the level of the water can be controlled to maximise the buoyancy effect from the water; also, the speed of the treadmill belt can be controlled to allow the animal extra time for voluntary motor function in the affected limbs. Moreover, the therapist will be in the water with the patient so she or he will be able to passively assist the patient to move his affected limbs in a functional pattern, when the patient is supported with a buoyancy jacket, sling and an over-treadmill hoist.

Reduce pain

The warmth of the water can reduce muscle tension and associated pain from trigger points allowing the patient to exercise in a comfortable environment. The hydrostatic pressure from the water can reduce pain in arthritic patients with swollen joints, and the buoyancy effect of the water ensures less bodyweight is passing through these joints and therefore reduces the concussive forces passing through the joints, so that the animal is able to exercise in a comfortable environment and therefore build muscle to support and stabilise the painful joints.

Improve stamina

The viscosity or resistance properties of water can be used to improve cardiovascular fitness and stamina. The duration of time exercising in the water treadmill can gradually be increased, with the rest intervals being gradually decreased. As the patient progresses the speed of the belt can also be increased. Finally, adding in resistance with water jets will improve stamina and strength.

Pool chemistry

A pool tester kit should be used to check the pH and bromine levels in the water storage tank at least once a day, or more frequently if the water is becoming contaminated between patients. The pH should be adjusted first, followed by the bromine.

Personnel must take care when handling these chemicals by wearing protective gloves to prevent skin irritation, protective googles to protect the eyes from splashes, and a face mask to prevent the chemicals from being inhaled.


The pH of the water is an indication of the acidity or alkalinity of water. The pH should be maintained between 7.2 and 7.6; when the water becomes contaminated with bacteria the pH will fall and the water will become more acidic. Aqua Sparkle Spa pH Plus (PoolMarket.co.uk, Bristol, UK) can be added when the level falls below 7.2, Aqua Sparkle Spa pH Minus (PoolMarket.co.uk, Bristol, UK) should be added to the storage tank if the level rises above 7.6. Ensure that any added pH powder is well mixed with the water in the storage tank.


Bromine is a chemical similar to chlorine used in swimming pools to prevent the water from becoming contaminated with bacteria. When the water becomes contaminated with bacteria the level of bromine will fall; the level of bromine should be maintained between 2 and 6 ppm (parts per million). Small quantities of bromine powder can be added to boost the level should the level drop below 2 ppm. Bromine tablets are also available, which slowly dissolve over a period of weeks in the tank to maintain a baseline bromine level within the storage tank.


The water should be maintained at a comfortable temperature for the animal to exercise in. A temperature of 30°C is recommended to reduce muscle tension or spasm and to provide the patient with optimum conditions to exercise in.

Properties of water


The density of an object is the ratio of the weight of the object relative to an equal volume of water (Haralson, 1988). Densities of various substances are defined by their specific gravity; the specific gravity of water is 1.0. The density and specific gravity of an object will determine how well it will float. If the ratio of the object’s specific gravity to that of water is greater than 1, the object will tend to sink, and if less than 1 the object will tend to float (Edlich et al., 1987).

A lean animal will have a higher specific gravity than water, and will be less buoyant in water than an obese animal, which will have a specific gravity lower than the water; hence the obese animal will tend to be more buoyant in water and float.


A body immersed in water will experience two opposing forces: gravity is the downward force, while buoyancy is the upward thrust of water acting on a body that creates an apparent decrease in the weight of the body while immersed (Hecox et al., 1994).

Weak animals can benefit from buoyancy as the weight passing through the limbs will be less, so the weak animal may find it easier to move and exercise in water. The same principles would apply to animals with painful joints: the buoyancy effect would result in less bodyweight and lower concussive forces passing through the joints, so the animal would be more comfortable exercising in water.


The viscosity of water, or its resistance, is significantly greater than that of air. The resistance from water can be used to strengthen muscles in animals and therefore support the joints, and also to improve cardiovascular fitness and stamina. The viscosity of the water can be used to increase support in neurological patients who may have significant balance deficits on dry land.

Hydrostatic pressure

The deeper the body is immersed in water the greater the hydrostatic pressure exerted on it. This pressure can be advantageous to animals with peripheral tissue oedema or swollen joints, such as arthritic patients, because the water pressure will exert a force on these tissues to gently reduce the tissue oedema and swelling around painful joints.

Water surface tension

Water molecules have a greater tendency to adhere together on the surface. Resistance to movement is slightly greater on the surface of water because there is more cohesion on the surface of the water (Hecox et al., 1994). Keep this in mind when setting the level of water for the patient to exercise in, and ensure the level and therefore surface tension of water corresponds to the muscle groups to be strengthened.

Hydrotherapy for specific conditions

Hydrotherapy can be a very useful modality in the rehabilitation of neurological patients, who will benefit from the buoyancy effect provided by the water. The buoyancy of the patient can be further enhanced by using flotation equipment such as buoyancy jackets. Very weak patients should also be fitted with a neck support float as they may find it difficult to maintain head control in the early rehabilitation stages.

It is vital that a trained member of staff goes into the water with paraparetic or tetraparetic patients to reassure them should they panic, and to assist them with movement of the affected limbs and support the patient as necessary. Paraparetic patients should be supported with a Helping Hand or The Soft Quick Lift™ sling attached to a hoist; this allows the person in the water with the patient to use their hands to facilitate movement of the patient’s affected weak limbs. A second person should be poolside at all times to assist as necessary.

Tetraparetic patients should be supported with a body sling attached to a hoist with two people available to assist the patient at all times; at least one person needs to be in the water with the patient to ensure patient safety and to assist the patient as necessary.

Remember that neurological patients will tire very quickly: even being supported in stance with a body sling whist the water chamber of an underwater treadmill (UWT) fills or empties can be enough to tire these patients in the early rehabilitation stages. Keep the sessions short, provide plenty of rest breaks, give the patient maximum support and utilise buoyancy aids and flotation devices.

After the hydrotherapy session remember to shampoo the patient to wash bromine from his coat, and dry him well so he does not become cold. If he is returning to the ward make sure he is correctly positioned, so that weak limbs are supported, and that he is kept covered with blankets and comfortably warm.

If spinal patients begin hydrotherapy before skin sutures or staples have been removed use a waterproof dressing to protect this area. When to start hydrotherapy in these patients will be at the discretion of the veterinary surgeon, and also depend on the confidence of the staff that carry out the hydrotherapy for this group of patients.

Jul 18, 2021 | Posted by in NURSING & ANIMAL CARE | Comments Off on 4: Hydrotherapy

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