Hydrotherapy is the use of water to aid in recovery from an injury. Water has a number of
properties that aid in recovery, especially in orthopedic and neurologic conditions. The main difference between exercising in water vs. on land is benefit of water resistance, viscosity, and buoyancy.
Resistance and Viscosity
Water provides resistance to movement, making it harder to move through than air. And since water resists movement in all directions, it can build strength in the muscles of both flexion and extension. This makes the exercise more efficient for building cardiovascular endurance and muscle strength and endurance. It also makes dogs exaggerate their normal gait, increasing range of motion in a functional way.
Viscosity of water may increase input to skin receptors, improving limb awareness (proprioception). It also supports the patient, so weak dogs can exercise with less risk of falling.
Buoyancy is the upward thrust that water places on a submerged body. This allows dogs to bear less weight on their limbs as they exercise.
When the water is filled to the level of the dog’s hock, he bears approximately 91% of his own body weight. For example, a 50 lb. dog only bears 45.5 lbs of his weight when exercising in water up to his hocks. As the water rises to the level of the stifle, he is only bearing 85% of his weight, or 42.5 lbs in our example. As the water is raised to the level of the greater trochanter (hip), he only bears 38% of his weight, or only 19 lbs in our 50 lb dog.
Hydrotherapy is helpful in rehabilitating the following conditions:
- Neurologic conditions that cause the dog to be weak in one or more leg, such as with intervertebral disc disease or fibrocartilagenous embolus. The movement of
the treadmill helps establish a normal gait pattern. Buoyancy helps the dog to stand. Resistance of the water helps with strengthening the muscles.
- Orthopedic conditions, such as arthritis or recovery from surgery. The resistance of the water exaggerates the gait, helping normal range of motion to return. Bouyancy allows for low impact exercise, decreasing the risk of injury to the joints.
- Weight loss and conditioning, especially when combined with a proper diet. Exercising in water is more efficient at burning calories and strengthening muscle than the equivalent exercise on land.