Water has long been used to facilitate orthopedic rehabilitation with the intent to return the client to normal functional levels as expediently as possible. In today’s world of managed care, the practitioner must remain diligent with a plan that is most effective in actualizing efficient treatment outcomes. The return of the patient to premorbid activities of daily living is dependent on the therapist recognizing musculoskeletal imbalances then prescribing effective exercise progressions. Where aquatic therapy fits in a patient’s treatment strategy is contingent on the therapist’s knowledge of the physical properties of water and the prompt use of such properties to the client’s benefit. Thus, it is imperative that practitioners seeing orthopedic clients take into account the following prior to considering water therapy as a treatment option:

1) What are the properties of water that can positively impact this diagnosis, and how will I manage them for positive patient outcomes?

2) What can this patient accomplish more effectively in the water, and when in the rehab spectrum should I use such treatment?

3) What is the specific role water will play in this patient’s rehab process?

Properties of Water and Positive Patient Outcomes

Several properties of water need to be considered when treating the orthopedic patient; while the benefits may seem obvious, specific underlying concerns may also negatively impact progress.

Buoyancy. An upward thrust equal to the weight of the fluid displaced,^1-2 buoyancy decreases joint-compression forces and weight-bearing, so movement through lower-extremity joints may be less painful. The positive implication for decreased pain with movement affords the patient an opportunity for early intervention and increased physical exertion. In addition, for those patients with weight-bearing restrictions, early reintroduction of the gait sequence will promote strength and positive neurological input. The water also affords such patient an opportunity to maintain cardiovascular fitness.³ Because buoyancy also facilitates movement in an upward direction, if used appropriately, it stimulates early range-of-motion (ROM) gains for the extremities.1,4 

Quite a few orthopedic conditions exist where the effects of buoyancy may prove detrimental to patient progress. Since there is an inverse proportion between water depth and muscle activation, as noted in a study comparing land and water vastus medialis obliqus firing,⁵ one must consider at what depths and when in the rehab process water ceases to be an effective modality. Additionally, since ligaments remodel according to compressive force, depths picked for treatment of an ACL-reconstructed patient become as critical as knowing when in this patient’s rehab the water becomes ineffective except for cardiovascular maintenance. Lastly, while studies have assigned weight-bearing ratios for specific depths,⁶ the therapist must be cognizant of the fact that with vigorous activity, these increase up to 76%.6,7 This becomes critical for the patient who is partially weight-bearing to 50% and is running in chest-deep water. While this activity might be pain-free, the weight-bearing restrictions are being violated at this depth and with this activity.

Viscosity. This is defined as friction between molecules of a liquid that cause resistance due to their adherence to one another.^1,2 Viscosity, a property well utilized in aquatic therapy, facilitates early triplanar strengthening that can mimic both functional and sport-specific movement patterns. Additionally, the thickness of water creates a setting where balance is not an issue, and patients can experiment with various motor programs at decreased speeds without the fear of falling.

A concern with the use of water for resistance training has to do with both the intensity of one’s workout and the choice of equipment. Without a clear understanding of how resistance equipment facilitates strength acquisition, therapists can use equipment that becomes difficult for the patient to manage. Moreover, without the correct equipment, a patient working with resistance may have a vastly distorted picture of his or her strength gains. Both pose a threat to prompt return to function.

Turbulence. Generally speaking, this is either the laminar or unsteady flow of water that increases impedance or drag forces.2 Used correctly, this increased resistance can facilitate strength gains through functional movement sequences. Specifically, such resistance in the form of jets can significantly improve trunk stabilization, usually without increased segmental pain.

However, one must consider when there is too much turbulence; movement sequences are so drastically altered that the benefits to functional gains is minimal at best. Therefore, the therapist must maintain activities in motor patterns that precisely resemble land-based movements.

Hydrostatic pressure. Defined as the pressure exerted by a molecule of fluid on an immersed body,1,2 it plays a role in the resolution of edema. Because it increases linearly with the depth of the water, it can substantially reduce lower-extremity swelling in patients submerged to at least chest-deep level. This decrease in edema, while usually temporary, assists with improved muscle activation during aquatic treatment.

As a therapist using water, it becomes imperative to recognize that the properties of water are the basis of treatment, and that those physical properties that can be of merit at the onset of treatment actually slow the rehab process in the later phases of orthopedic rehabilitation.

Water Versus Land Outcomes

Because treatment is based on not only effective but efficient return to functional status, one must always consider water within the context of what characteristics of rehab can be more effectively influenced in water than on land. ROM upgrades are one of the primary reasons for water usage early in the rehab process. Water can produce quantitative ROM upgrades, in part due to less pain and decreased stress on joints. The judicious utilization of buoyancy equipment can facilitate both upper- and lower-extremity improvements, oftentimes earlier than conventional land-based treatments. These ROM changes should be considered to be permanent, but must be maintained through land-based protocols.

Strength is another component of conventional orthopedic rehab that can usually be addressed earlier in water than on land. While water exercises are primarily concentric, intensities can be altered by increasing the surface area of equipment, increasing the speed of movement, changing the patient’s position in the water, or changing the depth of the water. Because of the decreased pain with exercise, it is imperative that both the patient and the therapist recognize overexertion by the rehabilitating structures. When patients complain of pain lasting longer than 8 hours after treatment, this is usually indicative of too aggressive work for the stage of healing. Once this is adjusted, strengthening can effectively be accomplished using aquatic treatments.

The true benefit of water therapy comes from the fact that triplanar movement can occur earlier due to viscosity’s unique property. If a specific stage of treatment indicates upgrades in resistance or in speed, a therapist well versed in exercises and equipment can facilitate positive strength gains necessary to transition to land-based progressions that replicate appropriate speeds for a given task.^8,9

With respect to gait reintroduction during lower-extremity rehab, it is critical to note that the biomechanics of water walking drastically differ from land’s normal gait sequence. Consider the action of the hamstrings in toe-off, for example. On land, they eccentrically decelerate the lower-extremity’s advancement; in the water, however, the swing phase is predominated by concentric contraction of the hip flexors to advance the limb forward prior to heel strike. Thus, early practice of the gait process to reset gross parameters of weight acceptance by the involved lower extremity does facilitate land’s approach to gait retraining. Additionally, since falling when in water is not a consideration, one can facilitate early weight-bearing with steps while in water.

Water Therapy’s Vital Role

The role of water in the total rehab continuum for a given patient is the decision of the therapist and, to a certain extent, the patient. While the discussion here has extolled the benefits of water, it becomes critical for the therapist to recognize at which point water is an efficient adjunct and when it is a detriment to progress.

In dealing with most extremity problems of an orthopedic nature, the focus early on is ROM acquisition. Buoyancy equipment can facilitate most straight-plane motions in a gentler fashion than does land treatment. Therapists can effect joint mobilizations for selected upper-extremity issues more easily, since one has direct access to posterior structures when the patient is supine. Lower-extremity movements can likewise be facilitated by the placement of buoyant cuffs. When working to increase ROM, it is easiest to keep the patient in chest- or shoulder-deep water.

Strength, as discussed above, can be addressed easily and can be isometric, concentric, or eccentric, depending on limb placement in relation to the surface. The use of jets or manual perturbations can also assist with specificity training for muscle firing. Strength can be addressed in either shallow or deep water, depending on several factors, including intensity of activity, patient tolerance, and the treatment goals. In addition, while there is a plethora of equipment used for strengthening, it is the pairing of one’s goals, the patient’s deficits, and the equipment intensity that is the mark of an expert water therapist. As with land treatments, equipment must remain challenging but not overpowering, and manageable but not too easy; and it must be well suited to water use for a task at hand.

Biomechanics retraining for both trunk and extremities must be addressed at the first treatment session, whether in water or on land. The therapist who remains fastidious with such cues will derive appropriate motor re-education. While the refraction of water makes this task somewhat more difficult for the therapist, without accurate input throughout treatment the patient is, in effect, only exercising … not rehabilitating. Such props as taping techniques can facilitate reprogramming appropriate biomechanics. Using the various body positions available in water can make such retraining feasible early in the rehab process.

For therapists who do use water therapy as a viable means to address orthopedic issues, the caveat remains early introduction of various treatment techniques versus the fact that water is different than land. However, by remaining diligent with one’s treatment goals, the patient has the best of both worlds—early advancement of ROM and triplanar strength, which transfers to early transition to land-based specificity of training. While water therapy is merely an adjunct or a tool in the rehab process, proper utilization usually accounts for early functional gains.

Marty Biondi, PT, CSCS, ATRIC, has been involved in aquatic therapy for 25 years and is part owner of an outpatient orthopedic practice. She has been honored to present at Aquatic Therapy and Rehab Institute’s professional conferences and is currently director of practice for the American Physical Therapy Association’s aquatic section.

References

1.Becker B, Cole A. Comprehensive Aquatic Therapy. 2nd ed. Boston, Mass: Butterworth-Heinemann; 2004:19–57,227–239.

2. Sova R, ed. Introduction to Aquatic Therapy and Rehab. Port Washington, Wis: DSL Ltd; 2004:15–37.

3. Wilder RP, Brennan DK. Physiologic responses to deep water running in athletes. Sports Med. 1993;16:374–380.

4. Norton C, Shaha S, Stewart L. Aquatic versus traditional therapy: contrasting effectiveness of acquisition rates. Salt Lake City, UT: Orthopedic Specialty Hospital.

5. Fuller RA, Awbrey BJ, Dye KK, et al. Activity level of the VMO during single leg mini squats on land and at varied water depths. J Aquatic Phys Ther. 1999;7:13–18.

6. Harrison RA, Bulstrode S. Percentage weight bearing during partial immersion in the hydrotherapy pool. Physiother Practice. 1987;3: 60–63.

7. Harrison RA, Hillma M, Bulstrode S. Loading of the lower limb when walking partially immersed: implications for clinical practice. Physiotherapy. 1992;78:164–166.

8. Ruoti R, Morris D, Cole A. Aquatic Rehabilitation. Philadelphia, Pa: Lippincott Williams & Wilkins; 1997: 59–126.

9. Robinson LE, Devor ST, Merrick MA, et al. The effects of land vs aquatic plyometrics on power, torque, velocity, and muscle soreness in women. J Strength Cond Res. 2004;18:84–91.