(Photo above: The Cross Country is an excellent general strength/conditioning exercise. The reciprocal motion and extended limbs creates resistance at high speeds and promotes gentle stretching at low speeds.)

By Katalin Wight, MPT, and Melisenda Edwards, MS

Many physical therapists know about shallow-water exercises, but deep water training may be a bit of a mystery, raising questions such as, “How does the patient stay afloat?” and “What kind of exercises would I do?” As it turns out, deep water therapy has unique applications as well as some that are consistent with shallow-water exercise. The book Deep End of the Pool Workouts, which I co-authored with Melisenda Edwards, sheds light on the rationale for water training, basic cardiovascular and respiratory components and benefits, and includes detailed descriptions of a number of full-body movements or strokes that can also be adapted to isolate muscle groups or body regions. Sections for each movement describe precautions and contraindications from a physical therapy perspective. There is a strong emphasis on general strength and endurance benefits as well as a chapter on how to instruct others from the deck. This article presents numerous points of interest and explores the effects of this type of training as a way to help inform the decision about whether to add this to a treatment repertoire.

[sidebar float=”right” width=”250]Product Resources

The following companies provide products for aquatic therapy:

Aquatic Access Inc

Endless Pools

Hudson Aquatic Systems LLC


Nespa Tiled Spas

NZ Manufacturing

Sprint Aquatics

Sure Hands Lift and Care Systems

SPRI Products


Deep Water Benefits

Deep water training is a versatile treatment option and adjunct to land-based therapy for a number of reasons, including the fact that it is appropriate for a wide range of ages, capabilities, and skill levels. A patient would, of course, need to be comfortable and feel secure in this environment regardless of the floatation mode used. For those who have a fear of water, the emotional discomfort would very likely detract from any of the therapeutic benefits. For others, the water may be a highly enjoyable and effective adjunct to land-based therapy that promotes a sense of calmness and relaxation. Warm water temperatures also have the effect of decreasing sympathetic nervous system activity, which is considered more subjective yet just as beneficial, especially for patients who are dealing with the stress of physical impairment, pain, and/or loss of function.

The non-impact environment is created by the use of a floatation belt, which fully suspends the body above the pool floor and essentially eliminates the effects of gravity. There is no fall risk in this situation, although water safety is paramount. The upright position that is maintained with the belt, ensuring that no appreciable energy expenditure is required to keep the head above the water, allows for a wide range of intensity levels. This suspended position naturally calls for contraction of core muscles to stabilize any limb movement, provided the patient is cued to maintain a particular trunk position or orientation. Because there is no closed kinetic chain in place, the stability of the core becomes the force against which the limbs move. These stabilizing muscles are then naturally recruited, providing the easy opportunity for spinal musculature engagement and strengthening—a primary player in many rehabilitation programs.

Posterior chain activation and strengthening is extremely effective and relatively easily accomplished. Goal setting can target a number of areas such as muscle strengthening, ROM, core stability, speed/cadence, power, and endurance/stamina, even for those whose initial levels are low on the continuum. Exercise parameters can be adjusted easily, for example, by using upper or lower limbs only, decreasing/increasing effort levels, gradually/rapidly progressing intensities, or varying exercise complexity. For more active patients, deep water not only provides options for targeting of sport-specific motions or movement patterns, but also can incorporate high-level cardiovascular training.

Exercise and Activity

Exercises in water can be of a gentle nature that promotes ROM or can be vigorous, based on a number of factors related to the characteristics of water. Density of water and the related drag experienced as limbs move through water in any direction, is one of the hallmarks of exercise in this environment. On land, the resistance to movement of air is essentially non-existent, and resistance for strengthening is created through body position changes to utilize gravity or resistance applied through equipment such as weights or pulleys. In some cases, strengthening with the desired angle or joint motion can be challenging to achieve. In the upright position in deep water, resistance is present in any direction.

[RELATED: Learn about compact, underwater treadmill units designed for individual use in Using Aquatic Therapy to Address Musculoskeletal Dysfunction.]

PROM exercises can utilize the buoyancy of the water to support and promote joint motion as the limbs essentially float away from the midline of the body. Gentle AROM can be engaged by moving slowly against drag or against the resistance of buoyancy as limbs are brought downward and toward a neutral position, such as in hip adduction from an abducted position or shoulder extension from a flexed position. Active assistive ROM can be introduced with patients moving limbs with assistance of buoyancy. In the water there also is no limitation or impediment to ROM, so joints can be mobilized in nearly any direction with small excursions or large excursions. The only limb movement that would not be fully supported in the water in the upright position would be shoulder flexion/abduction greater than approximately 90 degrees as the arm lifts above the water line. Were this movement highly desired for treatment, a patient could be floated in a supine position to allow for supported shoulder abduction beyond 90 degrees.

For active exercises in particular, the intensity of the movement is predicated on the speed of the movement, the surface area of the limb, and the degree of extension or length of the lever arm. In deep water it is possible to combine all three of these elements with all four limbs in motion to exponentially increase the exertion level. If this is the desired intention, core stability must be well-developed and proper form adhered to diligently. This is an effective application to elite athletes who participate at very high performance levels. Engagement at the high end of the spectrum is possible through exercise choice, and through intensity levels manipulated by parameters discussed above. In sports rehab, this platform can be used in cross-training for conditioning, strengthening, core stability, speed, and power without the strain of ground impact. Because of the variety of movements, water training can be adapted to target most isolated and combined movements that would be encountered in land-based sports. Furthermore, the speed and power components can be introduced and increased as the patient progresses in their program.

Effects on the Body

Hydrostatic pressure (HP) of water has a few beneficial as well as precautionary effects on the body’s physiology in relation to the cardiorespiratory, circulatory, and neurological/sensory systems. This pressure is greater as the water depth increases. When the body is in deep water, up to the neck, the lower body is subject to more HP than in shallow water. Some of the effects of this property are increased cardiac filling, increased cardiac output, decreased heart rate with average pool temps, threefold increase in O2 consumption at an equivalent speed of running as compared to land, increased work for inspiration—hence, respiratory muscle strengthening—and decreased edema. Precaution is advised when working with patients with chronic or serious heart conditions, and clearance from the physician for deep water exercise is highly recommended. HP also causes displacement of blood upward toward the core through the lymphatic and vascular systems, decreases sympathetic vasoconstriction, and lowers blood pressure.

Other beneficial effects on the body provided by the deep water environment related to the neurological system are decreased pain/pain modulation, and integration of proprioception and kinesthetic senses for improved balance, coordination, and postural control. This, of course, is especially advantageous for reducing fall risk in the elderly. With respect specifically to pain, this environment provides an opportunity for increased limb and body movement for those with physical impairments that limit land/gravity affected activity, or who may be non-ambulatory. The freedom of movement with gravity eliminated could allow a patient to engage in reciprocal full-body movements that simulate walking or even running for those patients who are perhaps non-ambulatory for any number of reasons, such as high fall risk or non-weight bearing on one or more lower limbs. I have effectively applied this type of exercise to an individual with healing pelvic fractures who was not yet full weight-bearing and had not been able to move her lower body reciprocally through a functional range for 2 months.

The breast stroke effectively engages the posterior chain. Reverse breast stroke targets shoulder external rotation and scapular retraction for postural and  shoulder stability.

The breast stroke effectively engages the posterior chain. Reverse breast stroke targets shoulder external rotation and scapular retraction for postural and shoulder stability.

Pools and Equipment

Required equipment, other than the pool itself, includes the floatation belt and potentially a pool lift. Floatation belts come in a variety of sizes and shapes. For those patients who have higher percentages of lean muscle mass, more floatation will be required. Some individuals may need two belts, one with the floatation pad anterior and the other posterior. Some who have higher percentages of body fat may need little or no floatation. A small belt may be needed, however, to assist in balancing floatation to assist with the upright positioning.

Several manufacturers provide pools to the physical therapy market that may be useful in creating a deep water environment. One manufacturer, Hudson Aquatic Systems LLC, Angola, Ind, offers in-ground pools with multiple depths available for exercise and therapy. These commercial-grade pools include the ability to monitor gait and range of motion through viewing windows, and are available in custom sizes and depths. Hudson Aquatic’s commercial pools also offer options such as spa jets and resistant swim currents. Another source for therapy and fitness pools is Middletown, Pa-headquartered HydroWorx, which offers the HydroWorx 200 Series, a variable-depth hydrotherapy pool with a moveable floor, underwater treadmill, and camera system.

For some aquatic settings an ADA-approved pool lift may be helpful for safe entry and exit from the water. ADA-compliant lifts meet the requirements for a fixed based fixed, seat size, arm and foot rest specifications, lift operation, and lift capacity (lbs). Among the versatile technologies available to the PT market to meet these standards are in-ground and above-ground lifts from Aquatic Access, Louisville, Ky. The company’s in-ground Model IGAT-180 is powered by water pressure, designed to lift up to 400 pounds, has a flip-up foot rest and seat belt, and does not require batteries to operate. The AG-48 WP is an above-ground lift built to lift over walls 31 inches tall, has a manual 360-degree seat turn, and can be mounted facing right, left, or straight out.

The Ranger Pool Lift by Aqua Creek Products, Missoula, Mont, is appropriate for smaller pools, which is likely the dimensions of a rehab clinic-located pool. The design is compact with stowed dimensions of 32 x 23.5 inches, and product weight is 130 lbs. It requires a 14- to 16-inch set back. The lift is detachable from the anchor, and a transport cart is available for convenient removal or storing. Another option, the aXs Pool Lift by S.R. Smith, Canby, Ore, has a low-profile design appropriate for simple pool designs. It is battery powered, and hand controls are water resistant. Setback range is 16 to 24 inches based on deck to water level. The lift itself locks into an above-ground anchor and allows for convenient 360-degree rotation.

Deep Thinking

Aquatic therapy in shallow water has demonstrated time-tested benefits for many types of physical therapy clients. One of the defining characteristics of aquatic therapy, however, is how it allows PTs to explore and engage their own creativity in constructing therapeutic activities for their patients. By moving into deep water, the opportunity to think critically and creatively about how to adapt activities for the best patient outcomes is renewed, and clinics and therapists who use deep water have a fresh opportunity to distinguish their brand. PTP

Katalin Wight, MPT, is a physical therapist in private practice. She received her Master’s Degree in Physical Therapy from the University of California at San Francisco, and has specialized in acute care rehab for 24 years. She has been active in organized sports in high school and at the university level.

Melisenda “Melis” Edwards, MS, holds a Master’s Degree in Health Promotion, a Bachelor’s Degree in Health Education, and several teaching and training certifications. She uses the pool environment to train a range of individuals from triathletes to professional hockey players, and has more than 30 years of experience as a running and triathlon coach. Edwards has participated in Ironman distance triathlons and the Western States 100-mile endurance run, and is founder of www.hitmethodfitness.com. For more information, contact [email protected].

More about this topic

Learn how to use aquatic therapy to treat spinal cord injury in this clinical feature by Jennifer L. Silvestri, MS, OTR/L, ScDs, CKPT, and Kimberly Perone, MBA, MSHA, OTR/L: Aquatic Therapy in Spinal Cord Injury.