PT Tip of the Month Archive


Maybe you've heard of them or even had one of them used on you during physical therapy. But what are they, and how do they work? There are many different types of modalities: moist heat, cryotherapy (ice), ultrasound, transcutaneous electrical nerve stimulation (TENS), neuromuscular electrical stimulation (NMES), iontophoresis, and low-level laser therapy (LLLT). Below is a brief description on each of these modalities, what the evidence says regarding them, and their uses.

Moist heat – Unlike heating pads, moist heat are packs stored in a device called, a hydrocollator, which keeps these packs in hot water prior to therapeutic use. During physical therapy, the moist heat is placed for 15-20 minutes on the exposed area that needs treatment. Moist heat is often uses to control acute and chronic pain as a result of various conditions (i.e. muscle strains, spasms, arthritis) or relax "tight" muscles or tissue. It also functions to cause vasodilation of the blood vessels, which allows for more blood flow and circulation to that area.

Cryotherapy – More commonly known as ice therapy and usually administered in the form of an ice pack, cryotherapy is used to decrease inflammation, pain, and edema in the affected area. It is usually recommended for management of acute injuries or after a great deal of therapy or exercise have been performed. Ice packs are usually administered for 10-20 minutes so that the cold can transfer through the skin and fat, into the muscle or tissue below. Cryotherapy causes vasoconstriction of the blood vessels in that area, which helps to decrease inflammation, and thus pain. It also works to reduce sensory nerve conduction at a physiological level, which is sufficient to induce a hypoalgesic effect (reduced sensitivity to pain).

Ultrasound – Physical therapists use therapeutic ultrasound (US) in order to warm muscle or connective tissue in the affected area. The theory is that the sound waves from the ultrasound head pass through the ultrasound gel into the tissue and helps to relax the tissue affected by muscle "tightness" or spasms, and promote vasodilation of the blood vessels to increase circulation and decrease inflammation. Presently ultrasound is a hot topic within the Physical Therapy profession as there is limited research as to the efficacy of therapeutic ultrasound.

TENS – A TENS unit uses electrical current to decrease pain due to injury. These units are portable and for the most part are battery-operated machine Electrodes are placed around the affected area and the current travels through the machine and electrodes to the exposed area. The patient experiences a tingling or pulsing sensation, which is actually disrupting the pain signals traveling down the surrounding nerves. This disruption causes the patient to feel less pain. TENS units may be used in conjunction with heat or cold therapy to control acute or chronic pain, manage post-surgical pain, or reduce post-traumatic acute pain.

NMES – Also known simply as E-stim, NMES can be used with the same machine but with various settings on the machine depending on the goal of the treatment. Like a TENS unit, E-stim uses electrical current and electrodes around the affected area. However, this type of modality is often used to promote muscle contraction in order to strengthen the muscle. For example, the Russian setting on an NMES machine utilizes a high frequency to allow for deeper muscle penetration via stimulation of the motor nerve, and thus a stronger and more forceful muscle contraction can occur. Another setting, called biphasic, has been used to maintain ROM, for muscle re-education, preventing joint contractures or muscle atrophy, increasing local blood flow, and decreasing muscle spasm. NMES is usually administered for 10-20 minutes as per therapist's discretion.

Iontopohoresis – This modality utilizes electrodes and electrical charge to "drive" medication into affected tissue. The electrically charged medication can be administered using a low current for an extended period of time, as in a dose-oriented treatment. Some of the uses for iontophoresis in delivering medication to tissues include: treating acute and chronic inflammation, arthritis, and myofascial pain.

Low-level laser therapy – LLLT is a very new and up and coming modality being used in physical therapy to assist with treating acute and chronic neck pain, rheumatoid arthritis, osteoarthritis, tendinopathy, and low back pain. The theory behind LLLT is unclear, but researchers hypothesize that LLLT works to reduce pain related to inflammation by reducing inflammatory mediators in the affected area or by causing an increase in ATP (the energy currency molecule of the cell), which affects cellular proliferation in the area. However, much more research needs to be conducted in order to know the efficacy and long-term results of LLLT.

One last intervention to discuss that is widely used in the field of physical therapy: McConnell taping. McConnell taping was developed by a physical therapist, Jenny McConnell. This taping method is commonly used to help alleviate pain in persons with patellofemoral pain syndrome (PFPS), which is one of the most common orthopedic problems experienced by women and runners. The causes of PFPS range from direct trauma to the knee, altered lower extremity biomechanics, tight/weak muscles or structures in the hip and thigh, or simply of insidious onset. Variations of McConnell taping have been used to correct patellar alignment, patellofemoral kinematics, and offset the compressive forces at the lateral aspect of the patellofemoral joint.

A recent study published in the March 2010 issue of Physical Therapy indicates that McConnell taping was shown to be effective in shifting the position of the patella inferiorly after exercise was performed. This shift resulted in increased contact area of the patella with the femur and is hypothesized to be responsible for some of the pain relief experienced by the subjects in the study. Other subjects with altered medial-lateral patellofemoral kinematics were able to experience relief with McConnell taping also. However, there needs to be larger-scaled randomized controlled trials to confirm the positive effects of this study.


Always consult your physician or licensed physical therapist before administering or receiving any of these modalities yourself, as there are many indications and contraindications with each modality. If you would like to schedule an evaluation, call 617-232-PAIN for our Brookline office, and 617-325-PAIN for our West Roxbury office.


  1. Beckerman H, de Bie RA, Bouter LM, et al. The efficacy of laser therapy for musculoskeletal and skin disorders: a criteria-based meta-analysis of randomized clinical trials. Phys Ther. 1992;72:483-491.

  2. Cetin N, Aytar A, Atalay A, Akman MN: Comparing hot pack, short-wave diathermy, ultrasound, and TENS on isokinetic strength, pain, and functional status of women with osteoarthritic knees: a single-blind, randomized, controlled trial. Am J Phys Med Rehabil. 2008;87:443–451.

  3. Costello CT, Jeske AH. Iontophoresis: applications in transdermal medication delivery. Phys Ther. 1995;75:554-563.

  4. Derasari A, Brindle TJ, Alter KE, Sheehan FT. McConnell taping shifts the patella inferiorly in patients with patellofemoral pain: a dynamic magnetic resonance imaging study. Phys Ther. 2010;90:411-19.

  5. Paxton SL. Clinical uses of TENS: a survey of physical therapists. Phys Ther. 1980;60:39-44.

  6. Starkey, Chad. Therapeutic Modalities. 3rd ed. Philadelphia: F.A. Davis, 2004. Print.

  7. Wong, RA, Schumann B, Townsend R, Phelps CA. A survey of therapeutic ultrasound use by physical therapists who are orthopaedic certified specialists. Phys Ther. 2007;87:986-994.

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