Aquatic Advantages

Athletic trainers who know how to harness the physical properties of water can accelerate their athletes’ return to sport.

By Jodie Humphrey

Jodie Humphrey, ATC, PT, CSCS, is a California-based freelance writer. She has worked as an athletic trainer at Dartmouth College, the University of Massachusetts, and Northeastern University.

Training & Conditioning, 12.5, July/August 2002,

Greek civilization was the first to recognize and appreciate the relation between state of mind and physical well-being, and in 460 BC, Hippocrates wrote of utilizing the properties of water to enhance this relationship. Today, athletic trainers carry on that therapeutic legacy by using water to augment and accelerate the rehabilitative process.

Pool-based aquatic rehab can help overcome biomechanical alterations in gait mechanics, range-of-motion deficits, swelling, muscular-strength deficits, power deficits, and limited soft-tissue mobility at the site of injury. What’s more, it’s indispensable in enabling the athlete to begin exercises sooner. This article provides a review of the science behind aquatic therapy, an explanation of some effective rehab techniques, and a sample aquatic rehab plan.

The properties of water that play the main role in pool rehabilitation are buoyancy, hydrostatic pressure, surface tension, and hydrodynamics. These are unique conditions that facilitate physiological changes to enhance recovery.

From a joint-protection perspective, the most important property of water is buoyancy. The upward thrust buoyancy exerts on an immersed body is helpful in rehab because it lessens the weight-bearing forces on the recovering muscles and joints.

Buoyancy is also “adjustable,” because an athlete’s weight-bearing proportion is decreased by increased depth in the pool. For example, when an athlete is submerged to the seventh cervical vertebrae, the forces at the spine and lower extremities equate to approximately 10 percent of land weight-bearing. Once the athlete moves shallower, to the xiphoid process depth or the superior pelvic rim, this equates to 25 percent of land weight-bearing and 50 percent of land weight-bearing, respectively.

This adjustability permits a patient to gradually advance to full-weight-bearing exercises over time. It not only protects the injury, it also gets an injured athlete jumping, hopping, and skipping much sooner than on land.

Hydrostatic pressure is the fluid pressure exerted equally on all surface areas of an immersed body at rest at a given depth. This aquatic property is most beneficial in edema management because it applies even pressure around an injured joint, even more than an elastic bandage. For example, the surrounding water pressure at the calf in neck-deep water applies 120 grams per cubic centimeter (g/cm3), where an elastic bandage applies approximately 55 g/cm3.

Natural water pressure can easily be paired with active muscle exercise to facilitate the venous drainage of the swelling without the variation in uniform compression that typically occurs with an elastic bandage wrap.

Surface tension is the force exerted between the surface molecules of a fluid. When an athlete’s limb is moved to the surface of the water, a force is necessary to overcome the fluid’s natural surface tension. This force can be applied to the athlete’s rehab and strength-training programs.

Hydrodynamics is another property of the aquatic environment that makes pool rehab especially useful. The natural drag of moving an arm or a leg through water can be used to create resistance or facilitate movements. In other words, as an athlete moves an arm or a leg increasingly faster through water, more force is necessary to overcome the viscosity of that water. That variable force, in turn, can provide a useful tool for progressively increasing resistance during rehab exercise.

Another important facet of hydrodynamics is that the greater the surface area of an object moving through water, the more force is needed to move it. Consequently, the concentric and eccentric demands on a muscle can be further challenged by increasing the athlete’s surface area using paddles or other aquatic-therapy equipment.

Pool-based rehab is also of great benefit because the athlete’s upper body can be put through advanced exercises in the early stages of the rehab process while the injured limb is protected by compression, by limited weight-bearing, and by enhanced sensorimotor input in the pool. For the rehab of lower-limb strength and power, the athlete’s ease with squatting, step-ups, and jumping are facilitated by the water’s properties. These tasks are gentler on the joint and muscle demand due to a combination of all the properties of water discussed above.

The pool provides a fun and dynamic environment to challenge the athlete and stimulate recovery from injury. Techniques employed in the pool are variable in their approach to rehab. Here are some typical techniques for rehabbing in the pool and their common applications.

Bad Ragaz is similar to proprioceptive neuromuscular facilitation in land-based therapy. The therapist provides the source of manual stability as well as resistance to a functional pattern of movement, typically by pushing or pulling against a movement that the athlete is making. Stability and resistance is attained with the athlete suspended at the surface supine with buoyancy belts. The athlete must perform a resisted movement such as hip abduction and adduction as the contralateral limb is challenged to stabilize the force of the body’s urge to rotate from this lower-extremity movement. Thus, bilateral hip stabilizers are being called upon to either move the limb or stabilize the opposite limb. This process enhances muscle activity to recruit the inactive muscle into the functional movement pattern.

Halliwick is similar to neurodevelopmental techniques employed on land. This philosophy and progression can be utilized to promote symmetrical balance and body awareness. It was originally inspired by a program for teaching children with cerebral palsy how to swim. Teaching those children to swim enabled them to gain an improved sense of body awareness to function on land.

Lumbar stabilization can be challenged in an aquatic environment for advanced core strengthening. The premise of the Halliwick technique is to maintain a “neutral” spine. This means that the normal spine curvature is maintained during exercise, while the athlete’s arms and legs provide the lever arm to increase core stabilization control. An example would be to have the athlete assume a vertical posture with feet dorsiflexed and unsupported in a sufficiently deep pool.

Simply maintaining this balanced isometric posture without any extraneous trunk or limb movement is the critical component to this approach.

Watsu is a passive relaxation technique that is indicated for pain and high stress and for muscle tension release. The athlete is cradled through a series of movements to facilitate relaxation. These movements are combined with accupressure to improve flexibility, range of motion, lessen pain, and improve general well-being.

Sport-specific training, in which land-based techniques are adapted to a pool setting at an earlier phase of healing, is common. Step-downs, squats, and lunges all can be made more difficult with equipment and applying the properties of water, such as hydrodynamics. Equipment utilized for pool-based sport-specific training includes buoyancy dumbbells, belts and boots, elastic bands, and balance boards. Plyometrics should be advanced with the same principles practiced in land programs, taking into consideration the partial weight-bearing forces the pool provides.

To illustrate how the properties of water and the various techniques are applied, the following is a sample pool rehab protocol for an athlete with a knee injury. It begins two weeks after the injury or surgery occurs and ends 24 weeks after the event. This pool rehab should be done in conjunction with land-based therapy. Both land-based and pool-based therapy should begin as soon as the attending physician or surgeon gives the green light. However, two weeks after injury or surgery is a typical time frame to begin pool-based therapy.

Weeks two through six:

The goals of this initial phase of pool rehab are to reduce the pain and swelling that is limiting function, to improve weight-bearing capabilities, and to increase active assisted range of motion.

• Have the athlete walk in chest-deep water with proper gait mechanics (emphasize heel strike with active quadriceps contraction for knee extension control through stance phase).

• Hamstring, hip flexor, gluteals, adductors, abductors, quadriceps, and gastroc-soleus complex active warmup and static stretches.

• Water endurance training using aqua jog, scissors, cross-country ski simulation, and neutral-spine treading water.

• Range of motion exercises for knee, hip, and ankle.

• Progress functional activities as tolerable: squatting, lateral stepping, toe/heel raises, step-ups and step-downs, lunge walking, jumping, hopping, skipping, bounding.

• Core and upper-extremity strengthening with weight-bearing at appropriate water depth.
Various exercises can include athlete in athletic stance or diagonal stance with dumbbells for shoulder flexion and extension, bilateral flys, alternate punches, bilateral shoulder adduction, abdominal crunches, and shoulder internal/external rotation by side and at 90 degrees scaption. Also, balance activities on wobble boards, kick boards, or dumbbells supported at the pool bottom provide a closed-chain activity. These activities, unsupported in deeper water, provide an open-chain activity.

• Watsu can be valuable to lessen pain and guarding from abnormal movement patterns. The stress imposed on the injured area can also be limited by many Watsu techniques.

• Bad Ragaz techniques to improve gait pattern coordination and promote functional isometric, and isotonic muscle activity.

Weeks seven through 12:

The goals of this period of pool rehab are to increase weight-bearing tolerance through joint surfaces with functional activities, such as jumping in shallow water. Also, this portion of the rehab process is designed to initiate gentle strengthening exercises for lower extremities; progress to upper extremity and core exercises with resistive bands, cuff boots, paddles, flippers, webbed gloves or ankle weights; restore full range of motion; improve high-level functional tolerance while jumping, jogging, and hopping; and to improve cardiovascular endurance.

• Be sure the athlete has progressed through the initial phase in weeks two through six. The jumping, hopping, skipping, step-downs, and other functional activities in deep water (athlete submerged to shoulders) should be progressed to shallow water (athlete submerged to waist).

• Range of motion or joint mobilization exercises should be implemented while the athlete is submerged to facilitate restoration of full range of motion.

• Initiate resisted lower-extremity exercises while taking into consideration the shear forces applied to the knee with any type of ankle-applied equipment.

• Have the athlete walk or run forward and backward with kick board for resistance while submerged to the chest level.

• Challenge the athlete’s balance by creating a turbulent flow by waving a kick board through the water in the periphery of the athlete while he or she assumes various balance re-training positions such as eyes closed and standing on one leg.

• Have the athlete use flippers for kicking for local endurance training in lower-extremity musculature.

Weeks 13 through 24:

The goals of this final phase of pool-based rehab are to transition the athlete up to a point where he or she is ready to return to sport-specific training. This phase should also be designed to initiate a circuit of combined land- and pool-based exercises that will provide some variation to the rehabilitation program.

Some exercises to consider for this phase are lap swimming for endurance, wall push-offs for distance, circuits involving entering and exiting the pool at various depths to perform land-based exercise alternated with pool-based exercise, and piggy-back or otherwise weighted jogging, squats, step-downs, and other functional activities in the pool.

Aquatic therapy is not a replacement for land-based rehab protocols. Instead, it should be applied as an adjunct to the techniques used in land-based rehabilitation. Your aquatic rehabilitation needs to have clear goals that dovetail with the land-based treatment that is specified for an athlete. But using this effective form of treatment is the fastest way to progress your athletes to those land-based exercises after injury or surgery. And with its mastery, your athletes will take to healing like a fish to water.

Sidebar: Water Hazards

As with any form of exercise, there are situations where pool-based rehabilitation is not recommended for individual athletes. If a
recovering athlete has any of the following conditions, he or she should not perform pool-based rehab:

• water-transmitted diseases such as hepatitis

• infections, particularly those with open sores

• fever

• diarrhea

• contagious skin rashes

• incontinence

There are other conditions where an athlete can do pool-based rehab, but
precautions—and the permission of the athlete’s physician—are necessary. These conditions include:

• respiratory disease such as asthma

• pregnancy

• cardiac conditions

• open wounds and non-healed incisions (occlusive dressings to minimize infection risk are available and can be worn in the pool if early entry into pool rehabilitation is needed)

• excessive fear of water