Blood is composed of mostly water. Muscle tissue is 75% water; hence EMS will greatly effect this tissue. Muscle tendons, bone, fat, and nerve have very little water.

PHYSIOLOGIC RESPONSES OF EMS

• Relaxation of muscle spasms.
• Simulation of active exercise.
• Muscle reeducation.
• Increased production of endorphins (decreases pain). This physiologic benefit occurs at the opiate pain control center. Electrical stimulation of sensory nerves stimulates the release of enkephalins from local sites throughout the central nervous system and the release of endorphins from the pituitary gland into the cerebrospinal fluid. Once the release of endorphins occurs, a reduction of, or elimination of pain perception, is the desired end result.
• Circulatory stimulation by the pumping action of the muscle. (Reduces inflammation and swelling)
• Increase in removal of cellular waste to promote healing and reduce swelling.
• Increase in range of motion. EMS stimulates a muscle to pull the joint through limited ranges. The continued contraction of this muscle group, over time, causes the contracted joint and muscle tissue to modify and lengthen.
• Pain reduction from stimulation of sensory nerves.

Clinically, efforts are made to stimulate the sensory nerves to change the patient's perception of a painful stimulus coming from the affected area of the patient. EMS does this by:

• Gate control to Change the perception of pain in the sensory fibers.
• Central biasing Stimulation of the C pain fibers which produce pain at the peripheral sites (areas of damage), can lessen the transmission of pain information by closing the pain gate at the spinal cord level.

WORKS CONSULTED
Kahn, Joseph. Principles and practice of Electrotherapy. Churchill Livingston Inc. ,1991. McDonland , D.C. C.C.R.D. Heather A. Thieme, M.A. , A.T.C. Guide to Therapeutic Modalities. 1991 Gersh, Merly. Electrotherapy in Rehabilitation. F.A. Davis Company. Philadelphia 1992.