Aquatic Therapy


Aquatic therapy encompasses any exercise or manual therapy completed in an aquatic environment. The benefits of aquatic therapy include the ability to offer prescriptive exercise that is functional without being painful. Balance exercises can be completed safely in an aquatic environment well before they can be attempted on land. Elevated metabolism resulting from the resistance provided by water helps to speed weight loss while increasing muscle strength. Underwater treadmill (UWTM) work adds the benefits of weight bearing while giving the therapist the option to quickly change water depth and tread speed as needed. The inherent properties of water, including buoyancy, hydrostatic pressure, viscosity, fluid dynamics, and resistance make aquatic training efficient for achieving rehabilitation and maintaining total fitness. Therapeutic swimming programs are designed using the same system of short-, middle-, and long-term goals described in Chapter 8. Swim sets are interspersed with rest sets during which manual therapies can be applied. Program goals include improving flexibility, strength, balance, coordination, postural awareness, speed, and endurance. Weekly reassessment visits determine the rate of progression of each program. Equipment used in therapeutic exercise includes life vests, harnesses, slings, balance equipment, leg weights, resistance mitts, and pool noodles. There are some breed-related swimming and UWTM characteristics about which the therapist must be aware before initiating a training session. UWTM variables include water temperature, tread speed, water depth, resistance, and duration. Assistive and resistive devices and techniques are employed, including balloons, flippers, and elastic hair bands, gait patterning, tail work, and facilitation.

Aquatic Therapy Introduction


Today, therapists, sports coaches, and trainers understand the many benefits of aquatic therapy. Scientific research regarding the physiology of human immersion in water and applying the knowledge of water properties to aquatic treatment has revolutionized sports medicine (Thein & McNamara, 1992; Ruoti & Al, 1997g).

Pain is a central and consistent symptom for many canine patients and contributes to the cycle of disuse atrophy and progressive disability. Water-based therapies help to make movement more comfortable, offering prescriptive exercise that is functional, mechanically correct, and muscularly challenging without being painful. A warm water environment (86–94 degrees) offers muscle relaxation that is soothing for many conditions. This is enhanced by hydrostatic pressure causing a swaddling effect on immersed body parts (Thein & McNamara, 1992; Ruoti & Al, 1997d; Jadelis et al., 2001).

Aquatic therapy challenges balance and coordination. Balance exercises can be attempted earlier and more safely in water than on land, providing early opportunities for limb, trunk, and postural training, resulting in improved strength, balance, and coordination (Ruoti & Al, 1997d; Jadelis et al., 2001; Stager & Tanner, 2004).

Aquatic therapy raises metabolism and can help with weight loss, decreasing fat, strengthening muscles, and reducing the deconditioning effects of immobility (Lavoie & Montpetit, 1986; Ruoti & Al, 1997d). Slow, steady swimming burns a higher percentage of fat than fast swimming in humans. Fast swimming uses carbohydrates and burns 500–700 cal/h. Swimming, whether slow or fast, can benefit patients seeking weight loss or muscle gain (see Webliography at the end of the chapter) (Stager & Tanner, 2004).

Swimming uses the body’s muscles more completely than other activities such as running. Heredity influences the distribution of muscle fiber types, making some breeds great sprinters and others slow steady swimmers (Stager & Tanner, 2004). The therapist must design a combined aquatic therapy program that focuses on the patient’s specific needs and targets the appropri­­ate muscle fibers. Human studies demonstrate improvement in lean body mass (especially lean leg mass), decreased body fat, and reduced waist to hip ratio when using an underwater treadmill (UWTM) rather than a land treadmill (Greene et al., 2009).

Passive range of motion (PROM) in man is improved in water compared to on land (Ruoti & Al, 1997a). Marsolais et al. reported that active range of motion (AROM), especially in the pelvic limbs, is greater with swimming and with water walking than with land walking (Marsolais et al., 2003).


Sutures and staples are generally removed prior to initiating aquatic therapy. Occasionally, with the surgeon’s approval, the advantages of early therapy outweigh the risks of aquatic therapy prior to suture removal. A precautionary treatment plan should be devised for patients with respiratory problems such as laryngeal paralysis or exertional dyspnea and those with behavioral issues such as mild aggression or dislike of water. Swimming during pregnancy can be offered if discussed with the primary veterinarian and exertion is minimal. Toy breed puppies and seniors must be kept warm throughout the session.

Physical Properties of Water Relevant to Canine Sports Medicine

The inherent properties of water make aquatic training efficient for achieving rehabilitation and maintaining total fitness (Bishop et al., 1989; Thein & McNamara, 1992).


Archimedes’ principle states that when a body is wholly or partially immersed in a fluid, it experiences an upward thrust equal to the weight of the displaced fluid. As water depth increases, weight bearing decreases, thus reducing the compressive forces on joints (Bates & Hanson, 1992d).

Due to buoyancy, PROM is greater in water than on land (Figure 9.1) (Thein & McNamara, 1992).

Figure 9.1 PROM in pool increases stretching by using the properties of water.


Hydrostatic Pressure

Pascal’s law states that fluid pressure is exerted equally on all surfaces of an immersed body at rest at a given depth; this pressure increases with the density of the fluid and depth of submersion. Hydrostatic pressure reduces limb edema and pooling of fluid and blood in superficial and deep tissues thereby encouraging healing and reducing complication rates. Hydrostatic pressure causes a decrease in nociceptor sensitivity resulting in pain reduction (Bates & Hanson, 1992e; Ruoti & Al, 1997e).

The hydrostatic effects on the cardiopulmonary system result in a central shift of the peripheral blood volume (Arborelius et al., 1972). This results in increased diuresis so patients may urinate large quantities shortly after swimming. Due to hydrostatic pressure, dogs with chest expansion problems related to congestive heart failure or pulmonary disease need careful monitoring.


Viscosity is the frictional resistance created by cohesiveness of fluid molecules. Water is 15 times more viscous than air, thus requiring more effort to move through it. Water walking for humans, with the water at shoulder height, requires 65% more effort than walking on land (Greene et al., 2009). Working against viscosity increases muscle strength, tone, and cardiac fitness (Ruoti & Al, 1997f). Viscosity helps weak canine patients to stand and walk before they can do so on land.

Fluid Dynamics

Hydrodynamic forces impact any object in water. These forces include laminal flow, frontal resistance, and drag. Laminal and turbulent flow affect effort. Laminal flow is the straight flow of water particles moving at one speed and in one direction. Resistance to movement increases with the velocity of flow. Turbulent flow is the interrupted flow of water particles in all directions, creating more dramatic pressure differentials. Here, resistance increases exponentially with velocity. These fluid dynamic principles have clinical application when designing swimming or UWTM programs (Ruoti & Al, 1997f). In swimming, friction and turbu­­lence are the dominant resistive factors (Hall et al., 1990; Ruoti & Al, 1997f). Faster swimming or water walking creates greater turbulence, resistance, and friction, and therefore increases exertion (Figure 9.2). This is advantageous for patients needing an intense workout but disadvantageous for patients that are anxious, thrashing, or deconditioned. Swimming or UWTM sessions will vary based on patient aptitude, comfort level, condition, and fitness.

Figure 9.2 Turbulence using resistance jets increases strength training and cardiopulmonary workout.


When applying these fluid dynamic principles to dogs as they swim, the hydrodynamic forces create a pressure differential between the front (high pressure) and pelvic (low pressure) limbs. Resulting eddies create tail suction, skin friction, and drag on the pelvic limbs. The pelvic limbs must respond with powerful kicking or they will sink.

Pressure differentials and turbulence challenge the postural muscles and balance mechanisms. This is advantageous for patients with balance and coordination impairments or those needing paraspinal muscle strengthening.


Resistance is controlled by speed, but surface area and equipment can also contribute (Abidin et al., 1988; Bates & Hanson, 1992f; Ruoti & Al, 1997b, 1997f). The speed of water flow is controlled with resistance jets (pool) or tread speed (UWTM). Surface area is controlled by water depth and equipment such as life vests, resistance mitts, and leg weights. Increased speed maximizes the plane effect when swimming, decreasing surface area in the water, and therefore decreasing resistance.

Therapeutic Swimming

Muscles are used differently when swimming than when weight bearing on land (Bates & Hanson, 1992c, 1992e). The authors have observed greater AROM of canine shoulders and elbows in swimming when compared to land walking. Aquatic therapy increases the comprehensive challenge to coordination, balance, and kinesthetic movement mechanisms (Bates & Hanson, 1992e). Stimulating neuroreceptors with swimming enhances early land walking in human patients (Bates & Hanson, 1992c; Grosee, 2009). The authors believe that these kinesthetic movement mechanisms also apply to dogs. Tetraparetic dogs can stand in water with minimal assistance or can swim using multiple limbs before they are able to stand or walk on land.

Designing a Conditioning Program for the Canine Athlete

Canine athletes use swimming for effective rehabilitation treatment after injury or surgery and for cross training (Zink, 1997; Millis et al., 2004). Service dogs, search and rescue dogs, and K-9 corps members benefit from the physical and psychological advantages of swimming. Conformation dogs benefit with improved muscle tone and better endurance.

The following is a list of advantages of cross training for canine athletes (Zink, 1997):

  • Utilizes commonly used performance muscle in a different way
  • Increases use of muscles that are used minimally on land
  • Increases joint flexibility due to greater PROM/AROM
  • Eliminates concussive forces to reduce joint compression/stress
  • Maximizes cardiac output and pulmonary conditioning
  • Provides a mental/psychological break from land training
  • Maintains high training levels off season
  • Allows return to performance sport with minimal training time
  • Reduces injury risk at early season competitions
  • Allows for intense exercise during warm, humid weather with no risk of overheating.

Getting Started

The canine rehabilitation professional should first obtain a subjective history that includes the patient’s comfort in water. Medical, surgical, and sports injury history, including comorbidities, medications, and supplements are obtained from the referring veterinarian. The objective findings are formulated during physical evaluation. All subjective and objective information is integrated to formulate a clinical assessment and aquatic therapy plan. Measurable outcome goals are es­­tablished with the owner. Overall condition and body condition score (BCS) are noted. The duration of disability and degree of muscle atrophy are considered. The owner’s ability to transport the dog to sessions is also considered. Each therapeutic program must be individualized and cannot be standardized or preformulated.

Program Progression

Preoperative Planning

Preoperative swimming allows the patient to become familiar with the pool and aquatic environment, reducing the incidence of postoperative mishaps at pool entry or exit, thrashing while swimming, and inability to rest quietly between sessions. The preoperative visit allows for client education and the opportunity for the owner to observe the progress of other patients with similar conditions.

Factors to Consider

Aquatic therapy is started conservatively, and increased according to the patient’s comfort and ability. Most patients initially need body contact with the therapist in the pool. The amount of physical contact and bonding depends on the patient’s comfort level and can be gradually reduced. Owners can be poolside to offer encouragement. Teaching pool commands such as “Rest” enhances responsiveness.

Swimming 1 minute in a therapeutic pool, with current (resistance and turbulence) and a warm water environment (88–90 degrees) is strenuous. A cool water pool with no resistance jets will allow for longer swim sets, while a warm water therapeutic pool with varying current requires shorter swim sets due to greater effort and likely fatigue (Bates & Hanson, 1992b). Vital signs are monitored by checking pulse, tongue color size and shape, ear temperature, and facial expression as well as alterations in swimming speed and emotional state (Table 9.1).

Table 9.1 Assessment of anxiety and fatigue when swimming

Anxiety Fatigue
Anxious facial expression (lips pulled back) Tired body posture
Rapid breathing/pulse Deep or irregular breathing
Thrashing forelimbs Slowed swim pace
Inability to rest Reluctance to Swim
Attempting to exit the pool Change in tongue color/shape

During a 30-minute treatment, swim sets include multiple swim/rest cycles. As confidence and stamina increase, the swimming duration is lengthened and intensified, and rest periods are shortened. During rest cycles, the therapist provides treatments such as massage, standing exercises, joint mobilizations, bodywork, and PROM (Hall et al., 1990; Bates & Hanson, 1992b; Ruoti & Al, 1997a, 1997c).

Program Goals, Principles, and Exercises

Aquatic therapy programs use the same rehabilitation principles and goals as land-based pro­­grams. The pool becomes the gym, so a myriad of exercises are offered. The primary goals for aquatic exercises are flexibility, strength, balance, coordination, postural awareness, movement, speed, and endurance (Bates & Hanson, 1992c; Grosee, 2009).


Flexibility is improved with PROM and joint mobilization provided during rest periods. Traction is also effectively applied. Hanging traction, which can be uncomfortable or impossible for large breed dogs on land, is tolerated very well in water (Figure 9.3). Hanging traction, in which the dog is suspended vertically with the head and shoulders held above the water, maximizes hip and spine stretch and can aid paraspinal relaxation.

Figure 9.3 Hanging traction safely stretches spine and hips.


Massage to release paraspinal trigger points and tail-pulls in water improve spinal mobility.

Active exercises that improve flexibility include using food lures for lateral cervical and thoracolumbar stretching while standing or luring the dog to swim in tight circles, zigzags, or serpentine patterns.


Strength is improved with exercises that initially consist of slow swimming sets with low or no current. Circle swimming increases the workout for the legs on the inside of the circle. Resistance can be applied by holding the harness or life vest while the dog swims. Standing exercises such as rhythmic stabilization and cross-leg or three-leg standing can be effectively done in water. Dancing is performed with the patient standing on the pelvic limbs while the front limbs rest on the pool edge or stair. This can be done safely in water before attempting the same exercise on land.

As strength improves, games are added, including multiple rapid ball chasing sprints. Quick repetition of swimming into high current is excellent for progressing strength training. Throwing a ball off a backdrop encourages treading water, and is an intense strengthening workout. These games are good strength-training exercises for the rehabilitating canine athlete, when vigorous land exercise or training is otherwise restricted. They also assist in preparing for returning to sports that require quick responsiveness, rapid acceleration, and speed while running and jumping. Leg weights and swim mitts (see Equipment Used with Therapeutic Swimming) can be added to increase resistance.


Balance is improved, especially for the neurologically impaired patient, with water-standing exercises. Swimming, especially in current (turbulence), requires body stabilization, which improves bal­ance. Patients under 40 lb can stand on a floating kick board (see pool equipment) to improve balance.


Coordination is improved with stationary and swimming exercises. Early limb movement from swimming helps to speed and improve gait sequencing on land (Lavoie & Montpetit, 1986, Bishop et al., 1989). Backward walking or lateral stepping is performed on the bench or stair to enhance coordi­nation (Figure 9.4). Shaking water from the coat after swimming helps to improve balance and coordination during early neurologic recovery.

Figure 9.4 Using wide stairs in the pool allows a safe entry and exit.


Postural Awareness

Postural awareness is improved during early neurologic recovery with exercises such as pendulum swings, turning or circling on the bench, or sit-to-stand exercises performed while on the step or bench. Many of the proprioceptive neuromuscular facilitation (PNF) exercises that are performed on land can be safely completed during aquatic therapy sessions. During swimming, especially with turbulent current, the trunk and core muscles work to stabilize posture. Swimming in tight circles, figure-8s, and zigzags further increase postural challenges.


As conditioning improves, the swimming speed increases with enthusiastic coaxing and the addition of lures and games. Water speed, managed with resistance jets, is also slowly increased to add the challenges of turbulence and resistance.


Endurance improves via increased duration of swimming sets. Initially, swimming sets may be as short as 1 minute. Each set is followed by a rest period, and the cycle is repeated four to six times, depending on tolerance. The therapist monitors weekly progress and steadily increases the duration of swimming time, reducing rest periods. Physical and emotional factors are considered including pulse, respiration, and evidence of anxiety. Progressively lengthened sets are especially beneficial for dogs returning to endurance sports that involve long distance running or sustained activities.

Assessment of Progress

Weekly review with the owner/handler identifies progress throughout the phases of aquatic therapy with the treatment plan and goals adjusted accordingly. Written progress notes, including functional status, muscle circumference, PROM, gait status, BCS, treatment summary, adjusted goals and plan, are sent to the referring veterinarian monthly.

An aquatic therapy maintenance program can be started once aquatic rehabilitation is completed or can be used for cross-training exercise. Maintenance programs are generally provided by a therapist, but some facilities offer self-swim programs for patients. Owners of performance dogs often desire self-swim programs.

Equipment Used with Therapeutic Swimming

Specific aquatic equipment is used to improve swimming and facilitate accomplishment of rehabilitation goals (Abidin et al., 1988; Bates & Hanson, 1992f; Ruoti & Al, 1997b).

Life Vests

A life vest provides control, improves leveling, and builds patient confidence. The life vest must be nonrestrictive to allow for complete motion of the shoulders and hips, and it must be easy to put on and take off.


Harnesses are used on canine athletes that have prior pool experience and dogs that no longer need a life vest. Harnesses must exhibit the same qualities as the life vest.


Slings are used for safe transitions into and out of the pool. The sling reduces potential injury from slipping or struggling at the pool stairs. Once the patient is comfortable with transitions into and out of the pool, sling use can be discontinued.

Head Wraps

Head wraps or snoods reduce the amount of head shaking by preventing water from entering the ears (Figure 9.5). Lamb’s wool (not cotton) contains lanolin and repels water. The wool can be applied to the ear canal and secured with the head wrap.

Jul 9, 2017 | Posted by in EQUINE MEDICINE | Comments Off on Aquatic Therapy
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