The special characteristics of water provide for potent therapeutic effects.





Whether provided in pools to facilitate movement and resistive exercise, or in tanks or baths to facilitate the warming or cooling of distal body parts, or even in handheld trigger pulsed streams, physical therapist assistant may use water to accomplish therapeutic goals.



Aquatic therapy entails body immersion in pools or large tanks. When immersed in water the body or body part is exposed to the unique properties and forces of water. These properties and forces may be exploited for therapeutic purposes.




Buoyancy


The force of buoyancy can be assistive or resistive. In the presence of muscle weakness, aquatic exercise moving from deep to shallow will be assisted by buoyancy. Clinicians may assist in placing patients in appropriate positions to achieve buoyancy assist postures.


Similarly, exercise moving from shallow to deep are buoyancy resistive activities and therefore can be used to increase strength and endurance.





Viscosity


As you likely recall one of water’s special physical characteristics is cohesion. Cohesion is the tendency for water molecules to “stick” to each other.

Cohesion is possible due to the uneven sharing of electrons within a water molecule creating a polar molecule with the hydrogen end more positive and the oxygen end more negative.

The oxygen end of one molecule arranges itself toward the hydrogen ends forming electrical attractions called hydrogen bonds.

Viscosity is the frictional resistance that results from cohesion and is a source of resistive exercise in aquatic therapy.


Drag


Drag is a corollary to viscosity. It is an opposite force exerted on motion parallel to the surface. Drag increases with velocity and surface area and serves as another resistive exercise variable.




Hydrostatic Pressure


Hydrostatic pressure is the pressure exerted on the surface of the body by water. The greater the depth, the greater the pressure. Therefore more pressure is exerted on the feet than the chest.

However, this hydrostatic pressure can restrict chest expansion and contribute to respiratory compromise during aquatic exercise.

Clinicians must constantly assess patient for signs of respiratory compromise.



Temperature


You already understand the physiological effects of heat and cold. Manipulating the temperature of water is critical to goal attainment.




Whirlpool


Whirlpool therapy uses varied size stainless steel tanks with turbines attached to agitate and direct streams of water to treatment sites.

In medical settings whirlpool was used to manage and promote the healing of open wounds.

However, issues related to proper cleaning of the tanks, and the risks of cross infection have remained a concern.

Whirlpool therapy is still used in athletic training rooms and sports therapy facilities primarily to deliver cryotherapy to joints and unbroken skin.

In medical facilities whirlpool has been largely replaced with pulsed lavage with suction.




Pulsed Lavage with Suction

(PLWS)


PLWS is replacing whirlpool management of open wounds caused by pressure,peripheral vascular disease, surgical complications, and other causes. It has been shown to be effective, cost effective, more patient friendly, and safer than previous whirlpool management.