Canine Hydrotherapy: Evidence-Based Practice

Within the field of Veterinary Rehabilitation we know that our body of good quality research is limited, but growing. When it comes to canine hydrotherapy, the research is even more limited, and growing far more slowly. There are few research articles we can cite to the owners of our canine patients, and most convey only the beginning phases of the research. Much needs to be done in each of the areas currently being investigated.

The evidence discussed below provides guidance on the use of the underwater treadmill (UWT) through several key findings:

• We can influence and reduce the significant ground reaction forces experienced by canine patients in the UWT.
• We can influence limb kinematics, in that both the swing phase and stride length increase with increasing water depths.
• Swimming and use of the UWT can influence the range of motion of the post-operative CCL dog, improving flexion.
• The workload of the longissimus dorsi and gluteus medius decreases as water depth increases in the UWT.
• The ideal water temperature to avoid tachycardia, hyperventilation and hyperthermia in swimming dogs seems to be 33°C.

Below are summaries of six research articles that you can reference when chatting to vets and owners about your canine patients, and when making clinical decisions.

Effects of partial immersion in water on vertical ground reaction forces and weight distribution in dogs by David Levine, PhD; Denis J. Marcellin-Little, DEDV; Darryl L. Millis, DVM, MS; Verena Tragauer, Mag Med Vet; Jason A. Osborne, PhD.

This well-known paper demonstrates changes in weight bearing and weight distribution in relation to the height of the water; weight bearing is reduced by 15% when the water is at the height of the stifle, and by 62% when the water is at the level of the hip joint.

Interestingly, the weight distribution between fore and hind limbs was that 64% of the weight was carried on the forelimbs, both when water levels were at the height of the tarsus and the height of the stifle.  Significantly, weight bearing on the forelimbs increased to 71% when the water level was at the height of the hip.

This study used a sample size of ten dogs.

The effect of water depth on limb kinematics of the domestic dog during underwater treadmill exercise by F. Barnicoat and A. P. Willsa.

Barnicoat et al. performed a kinematic analysis in the underwater treadmill at various water depths to assess the effect of water level on the stride of healthy dogs. They found a significant reduction in duty cycle with increasing water depth. The swing phase and stride length increased as water depth increased, while the stride frequency decreased as the water depth increased.

This study used a sample of eight clinically sound dogs, over two sessions.

Kinematic analysis of the hind limb during swimming and walking in healthy dogs and dogs with surgically corrected cranial cruciate ligament rupture by Gregory S. Marsolais, DVM, MS; Scott McLean, PhD; Tim Derrick, PhD; Michael G. Conzemius, DVM, PhD, DACVS

Marsolais et al. determined that for healthy dogs, swimming results in a greater range of motion in the hip joint than walking, but that for CCLR dogs, swimming showed no increase in ROM of the hip joint than walking.  In both groups of dogs, swimming produced greater flexion and therefore ROM of the stifle and the tarsal joints. The ROM of the stifle in the surgical dogs was much less than in healthy dogs, in both walking and swimming.

This study included thirteen healthy dogs and seven dogs with CCL ruptures.

Aquatic treadmill water level influence on pelvic limb kinematics in cranial cruciate ligament-deficient dogs with surgically stabilised stifles by Bertocci, C. Smalley, N. Brown, K. Bialczak and D. Carroll

Bertocci et al. determined that the water level in an underwater treadmill influenced pelvic limb kinematics and temporal gait outcomes. As the water level increases, stifle flexion increases, with the greatest amount of stifle flexion shown when the water was at the level of the stifle and the hip. Hip flexion increased when the water level was at hip height. The stance phase of the stride also decreased when the water level was at the height of the hip.

Ten dogs were included in this study.

Effect of water depth on muscle activity of dogs when walking on a water treadmill by S. Parkinson, A.P. Wills, G. Tabor and J.M. Williams

Using surface electromyography on dogs walking on the underwater treadmill, Williams et al. determined that longissimus dorsi and gluteus medius muscle activation is affected by water depth. As the water depth increased, the average workload of the gluteus medius and the longissimus dorsi decreased.

This study included seven dogs.

Physiological effects of water temperatures in swimming toy breed dogs, K. Nganvongpanit, T. Boonchai, O. Taothong and A. Sathanawongs

This study looked at the effect of water temperature on the heart and respiratory rate during swimming, and changes in rectal temperature, blood glucose and blood lactate before and after swimming in 21 small-breed dogs in water temperatures of 25°, 33° and 37°C. The heart rate and respiratory rate were monitored every five minutes during a 20-min. swim, while the other parameters were measured before and after swimming. They found the highest respiratory rate in dogs swimming in 25°C water, and the highest heart rate in dogs swimming in 37°C water. Their recommendation to avoid tachycardia, hyperventilation and hyperthermia is to swim dogs in water that is 33°C.

This study included 21 small breed dogs.

Useful but limited

‘Literature is lacking in the area of water exercising and therapy in canine literature. Within the existing literature, huge variability exists as to hydrotherapy parameters and recommendations.’ Laurie Edge Hughes.

In each one of these papers, we learn something that has clinical relevance to as as hydrotherapists. However, all of these studies also have significant limitations. And so, while we can take something from each paper, we are sorely in need of more research in the field of canine hydrotherapy to be able to fully develop beneficial protocols for rehabilitation, and most importantly to provide an evidence-based approach to the use of this modality.

We need to establish the biomechanical effects of walking and swimming in larger populations of healthy dogs, and across different breeds. We need to establish the effect of hydrotherapy on spinal motion and the muscle activation and recruitment of different muscle groups. And we need to repeat all of this in patient populations with specific conditions.

Let’s do this, guys. If you have a treadmill or pool and an enquiring mind, let’s generate the research that will develop our field!

Resources

1. Download our FREE research citation booklet to keep track of the research relevant to you.
2. Watch Adapting your hydro protocol, with Ellen Martens, for free.
3. Read The tendencies and challenges of different breeds during hydrotherapy
4. Read Achieving goals of hydrotherapy with tools
5. Read Understanding swimmers syndrome

References

1. Barnicoat, F.  & Willsa, A. P.  (2016). The effect of water depth on limb kinematics of the domestic dog during underwater treadmill exercise.
2. Bertocci, G., Smalley, C., Brown, N., Bialczak , K. & Carroll, D. (2020). Aquatic treadmill water level influence on pelvic limb kinematics in cranial cruciate ligament-deficient dogs with surgically stabilised stifles.
3. Edge-Hughes, L. (2007). Underwater treadmill therapy in dogs: Finding the evidence to create a protocol for its use. A small scale sample literature review.
4. Levine, D., Marcellin-Little, D.J., Millis, D.L., Tragauer, V. & Osborne, J.A. (2010). Effects of partial immersion in water on vertical ground reaction forces and weight distribution in dogs.
5. Marsolais, G.S., McLean, S., Derrick, T. & Conzemius, M.G. (2003). Kinematic analysis of the hind limb during swimming and walking in healthy dogs and dogs with surgically corrected cranial cruciate ligament rupture.
6. Parkinson, S., Wills, A.P.,  Tabor, G. & Williams, J.M. (2018). Effect of water depth on muscle activity of dogs when walking on a water treadmill.