Physical Therapy Modalities

The primary goal of physical therapists (PTs) is to promote and restore proper movement to the human body. Limitations could include weakness, deficient balance or coordination, lack of range of motion or other factors. Fixing these issues can involve several strategies and procedures. Some of them, like strengthening and stretching, are familiar, while others are not. Several of the less familiar options will be discussed here. 

One of the terms used to describe the treatments used by PTs is “modalities,” specifically defined as ways of applying heat, cold, electricity, or another physical agent like low level lasers to the body to induce a desired effect. Those effects could be increased circulation, decreased pain or both, or even an improved anti-inflammatory condition. We will start with those modalities that deal with heat and cold.


Moist hot packs are commonly used for the application of superficial heat to the body. Generally, these packs are kept in a heater containing water at about 160 degrees. Superficial heating can help increase local circulation to a depth of about 1 centimeter from the surface of the skin. An option for heating at greater depths is ultrasound. When used on the 100-percent cycle setting, the ultrafast sound waves (hence the name) applied with a specialized machine can produce heat as deep as 3 centimeters. Heating can help with muscle relaxation, increased extensibility (stretchiness) and improved localized circulation. Low level lasers are a newer treatment in the United States that may also improve localized circulation, helpful in the reduction of swelling and pain.

Ultrasound can also be applied with a pulse setting of less than 100 percent (continuously producing sound waves). The effects of this treatment reach the same depth, about 3 centimeters, but don't produce heat. Without heating, the sound waves simply vibrate the tissue cells like those of the muscles, tendons or ligaments. This vibration may improve pain and tissue extensibility.

Cold treatments (cryotherapy) can range from ice or gel packs to ice massage. The two primary goals of cryotherapy are to reduce pain and decrease circulation. Pain reduction occurs from the slowing of nerve fibers carrying the message of pain to the brain. Decreased circulation helps decrease swelling by keeping fluid from building up as the inflammatory process progresses.

For pain reduction, there are several forms of electrical stimulation. Electricity is applied, in a very controlled way, to the surface of the skin through adhesive electrodes. The electrical current stimulates certain receptors in the skin that can override the sensation of pain from the site of injury. This works in much the same way as rubbing an injured area decreases the feeling of pain after a sudden impact. Electricity can also be used for other effects, including producing muscle contractions for muscle reeducation or delivering medication through the skin. Electrical stimulation used for muscle reeducation is designed to help muscles regain strength and control after a surgery or nerve injury. 

Delivering medication through the skin, iontophoresis, is a very specific form of electrical stimulation showing significantly improved safety and convenience for patients. It uses a low level electrical current to help push a pain and anti-inflammatory medication (often dexamethasone) through the skin to an area of injury without use of a needle for injection. The treatment works only for treatment areas that are within 1 centimeter of the skin surface (elbow tendons, knee tendons, ankles, etc.).

As with any treatment, you must consider the best choice. Many of these treatments are for pain reduction and some for the specific goal of healing. It is rare that the treatments listed above are the only modalities used. Addressing the causes of the of the pain (usually related to how the body moves) is the most important aspect of rehabilitation and treatment. Again, your therapist or health practitioner should give you clear therapeutic reasons and options to get you get back to your normal life and activity.


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