Spine & Injury Centers

Electrical muscle stimulation (EMS), also known as neuromuscular electrical stimulation (NMES), is the elicitation of muscle contraction using electric impulses. The impulses are generated by a device and delivered through electrodes on the skin in direct proximity to the muscles to be stimulated. The impulses mimic the action potentialcentral nervous system, causing the muscles to contract. In the United States, EMS devices are regulated by the FDA.

EMS causes adaptation, i.e. training, of muscle fibers.  Because of the characteristics of skeletal muscle fibers, different types of fibers can be activated to differing degrees by different types of EMS, and the modifications induced depend on the pattern of EMS activity.  These patterns, referred to as protocols or programs, will cause a different response from contraction of different fiber types. Some programs will improve fatigue resistance, i.e. endurance, others will increase force production.

In medicine EMS is used for rehabilitation purposes, for instance in the prevention of disuse muscle atrophy which can occur for example after musculoskeletal injuries, such as damage to bones, joints, muscles, ligaments and tendons.