Electrical muscle stimulation, also called EMS, is a type of therapy in which electrical impulses are generated by a machine and travel through electrodes on the patient's skin and then into their muscles. The electrical impulses mimic the central nervous system's impulses and cause the muscle to contract. Usually, electrical muscle stimulation is used in therapeutic applications, but some athletes use it for sports training purposes as well.
In 1783, Italian scientist Luigi Galvani was dissecting a frog on a table where he previously conducted experiments in static electricity. Galvani's assistant picked up a metal scalpel and accidentally brushed the frog's sciatic nerve. The leg kicked as if the frog were alive. This incident led Galvani to believe that muscles act on electric impulses. Research over the past two centuries has shown that electric muscle stimulation can elicit long-term change in muscles.
Methods For Electrode Placement
There are two generally accepted methods for using electrical muscle stimulation to heal injuries. The first method involves placing one electrode in direct contact with the wound and another electrode in contact with healthy, unaffected skin. The second method involves placing the two electrodes on opposite sides of the wound. Healing is aided by the negative polarity surrounding the wound, which increases the formation of tissue over the wound, thus speeding up the recovery process.
Applications for General Fitness
There are many electrical muscle stimulation machines on the market for the general public. Marketers for these machines often claim that consumers will be able to lose weight without exercising, tone their muscles, and even increase the size of muscles. Currently, there are no studies that show these claims to be true. However, many people claim that they've been able to lose weight and tone their muscles using electrical muscle stimulation devices.
NASA has used electrical muscle stimulation machines to help astronauts returning from space to rebuild their atrophied muscles. The electrical muscle stimulation machines improve blood flow to the muscles, and therefore, the astronauts can increase the efficacy of their workouts.
Patients recovering from paralysis have also benefited from electrical muscle stimulation. This doesn't always work, but sometimes the electrical impulses help the muscles to regain their functionality after a traumatic event.
If used improperly, electrical muscle stimulation can be harmful. Used at a too-high setting, muscles can be injured by overstimulation. In 1971, a federal judge stated that electrical muscle stimulation could cause miscarriages and aggravate pre-existing conditions such as ulcers, hernias, epilepsy and varicose veins.