Electronic Muscle Stimulation
Encyclopedia
Electrical muscle stimulation (EMS), also known as neuromuscular electrical stimulation (NMES) or electromyostimulation, is the elicitation of muscle contraction
using electric impulses. EMS has received increasing attention in the last few years, because it has the potential to serve as: a strength training tool for healthy subjects and athletes; a rehabilitation and preventive tool for partially- or totally immobilized patients
a testing tool for evaluating the neural and/or muscular function in vivo; a post-exercise recovery tool for athletes. 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 potential
coming from the central nervous system
, causing the muscles to contract. The electrodes are generally pads that adhere to the skin. EMS is cited by renown sport scientists as complementary technique for sport training, and published research is available. on the results obtained. In the United States, EMS devices are regulated by the U.S. Food and Drug Administration (FDA).
The XVIII Congress of the International Society of Electrophysiology and Kinesiology (ISEK 2010), which took place in Aalborg, Denmark on 16–19 June 2010, had a dedicated session on the subject: Electrical stimulation for testing and training in exercise and sports. As part of it, numerous research papers and reviews have been published
.
(1791) provided the first scientific evidence that current can activate muscle. During the 19th and 20th century researchers studied and documented the exact electrical properties that generate muscle movement. It was discovered that the body functions induced by electrical stimulation caused long-term changes in the muscles. In the '60s Soviet sport scientists applied EMS in the training of elite athletes, claiming 40% force gains. In the '70s these studies were shared during conferences with the Western sport establishments. However, results were conflicting, perhaps because the mechanisms in which EMS acted was poorly understood. Recent medical physiology research
pinpointed the mechanisms by which electrical stimulation causes adaptation of cells of muscles, blood vessels and nerves.
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 Physical therapy
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. However, this should not be confused with TENS (Transcutaneous Electrical Nerve Stimulator
): the use of electric current in pain therapy.
Because of the effect that strengthened and toned muscles have on appearance (a stronger muscle has larger cross-section), EMS is also used by a niche of practitioners for aesthetics goals. The FDA rejects certification of devices that claim weight reduction. EMS devices cause a calorie burning that is marginal at best: calories are burnt in significant amount only when most of the body is involved in physical exercise: several muscles, the heart and the respiratory system are all engaged at once. In general, spot reduction
of fat deposits by exercising only a few muscles underneath, voluntarily or electrically, does not work.
In EMS training few muscular groups are targeted at the same time, for specific training goals. The effectiveness of the devices for sport training has been debated. A niche of coaches regularly use professional EMS devices as integral part of the training of their athletes; some of these are high profile coaches, such as track coach Charlie Francis
, who used the technique to supplement the training of Olympic-level athletes. Non-professional devices target home-market consumers with wearable units in which EMS circuitry is contained in belt-like garments (ab toning belts) or other clothing items.
The FDA mandates that manuals prominently display contraindication, warnings, precautions and adverse reactions, including: no use for wearer of pacemaker; no use on vital parts, such as carotid sinus nerves, across the chest, or across the brain; caution in the use during pregnancy, menstruation, and other particular conditions that may be affected by muscle contractions; potential adverse effects include skin irritations and burns
Only FDA-certified devices can be lawfully sold in the US without medical prescription. These can be found at the corresponding FDA webpage for certified devices. The FTC has cracked down on consumer EMS devices that made unsubstantiated claims; many have been removed from the market, some have obtained FDA certification.
Muscle contraction
Muscle fiber generates tension through the action of actin and myosin cross-bridge cycling. While under tension, the muscle may lengthen, shorten, or remain the same...
using electric impulses. EMS has received increasing attention in the last few years, because it has the potential to serve as: a strength training tool for healthy subjects and athletes; a rehabilitation and preventive tool for partially- or totally immobilized patients
a testing tool for evaluating the neural and/or muscular function in vivo; a post-exercise recovery tool for athletes. 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 potential
Action potential
In physiology, an action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, and...
coming from the central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
, causing the muscles to contract. The electrodes are generally pads that adhere to the skin. EMS is cited by renown sport scientists as complementary technique for sport training, and published research is available. on the results obtained. In the United States, EMS devices are regulated by the U.S. Food and Drug Administration (FDA).
The XVIII Congress of the International Society of Electrophysiology and Kinesiology (ISEK 2010), which took place in Aalborg, Denmark on 16–19 June 2010, had a dedicated session on the subject: Electrical stimulation for testing and training in exercise and sports. As part of it, numerous research papers and reviews have been published
.
History
Luigi GalvaniLuigi Galvani
Luigi Aloisio Galvani was an Italian physician and physicist who lived and died in Bologna. In 1791, he discovered that the muscles of dead frogs legs twitched when struck by a spark...
(1791) provided the first scientific evidence that current can activate muscle. During the 19th and 20th century researchers studied and documented the exact electrical properties that generate muscle movement. It was discovered that the body functions induced by electrical stimulation caused long-term changes in the muscles. In the '60s Soviet sport scientists applied EMS in the training of elite athletes, claiming 40% force gains. In the '70s these studies were shared during conferences with the Western sport establishments. However, results were conflicting, perhaps because the mechanisms in which EMS acted was poorly understood. Recent medical physiology research
pinpointed the mechanisms by which electrical stimulation causes adaptation of cells of muscles, blood vessels and nerves.
Theory
EMS causes adaptation, i.e. training, of muscle fibers. Because of the characteristics of skeletal muscleSkeletal muscle
Skeletal muscle is a form of striated muscle tissue existing under control of the somatic nervous system- i.e. it is voluntarily controlled. It is one of three major muscle types, the others being cardiac and smooth 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.
Use
EMS can be used both as a training, therapeutic, and cosmetic tool.In medicine EMS is used for rehabilitation purposes, for instance in Physical therapy
Physical therapy
Physical therapy , often abbreviated PT, is a health care profession. Physical therapy is concerned with identifying and maximizing quality of life and movement potential within the spheres of promotion, prevention, diagnosis, treatment/intervention,and rehabilitation...
in the prevention of disuse muscle atrophy which can occur for example after musculoskeletal injuries
Musculoskeletal injury
Musculoskeletal injury refers to damage of muscular or skeletal systems, which is usually due to a strenuous activity. In one study, roughly 25% of approximately 6300 adults received a musculoskeletal injury of some sort within 12 months—of which 83% were activity-related...
, such as damage to bones, joints, muscles, ligaments and tendons. However, this should not be confused with TENS (Transcutaneous Electrical Nerve Stimulator
Transcutaneous Electrical Nerve Stimulator
Transcutaneous electrical nerve stimulation is the use of electric current produced by a device to stimulate the nerves for therapeutic purposes...
): the use of electric current in pain therapy.
Because of the effect that strengthened and toned muscles have on appearance (a stronger muscle has larger cross-section), EMS is also used by a niche of practitioners for aesthetics goals. The FDA rejects certification of devices that claim weight reduction. EMS devices cause a calorie burning that is marginal at best: calories are burnt in significant amount only when most of the body is involved in physical exercise: several muscles, the heart and the respiratory system are all engaged at once. In general, spot reduction
Spot reduction
Spot reduction refers to the belief, long viewed as a myth, that fat can be targeted for reduction from a specific area of the body. There is a common view, although many people believe that view is misguided, that it is possible to achieve spot reduction through exercise of specific muscles in...
of fat deposits by exercising only a few muscles underneath, voluntarily or electrically, does not work.
In EMS training few muscular groups are targeted at the same time, for specific training goals. The effectiveness of the devices for sport training has been debated. A niche of coaches regularly use professional EMS devices as integral part of the training of their athletes; some of these are high profile coaches, such as track coach Charlie Francis
Charlie Francis
Charles Merrick "Charlie" Francis was a sprint coach most noteworthy for being the trainer of sprinter Ben Johnson, the first competitor to be stripped of an Olympic gold medal for using banned drugs, and sprinters Angella Issajenko, Mark McKoy, and Desai Williams...
, who used the technique to supplement the training of Olympic-level athletes. Non-professional devices target home-market consumers with wearable units in which EMS circuitry is contained in belt-like garments (ab toning belts) or other clothing items.
FDA certification
The U.S. Food and Drug Administration (FDA) certifies and releases EMS devices into two broad categories: over-the counter devices (OTC), and prescription devices. OTC devices are marketable only for muscle toning; prescription devices can only be purchased with a medical prescription for therapy and should be used under supervision of an authorized practitioner, for the following uses:- Relaxation of muscle spasms;
- Prevention or retardation of disuse atrophy;
- Increasing local blood circulation;
- Muscle re-education;
- Immediate post-surgical stimulation of calf muscles to prevent venous thrombosisVenous thrombosisA venous thrombosis is a blood clot that forms within a vein. A venous thrombosis is a blood clot that forms within a vein. A venous thrombosis is a blood clot that forms within a vein. (Thrombosis is a medical term for blood clotting (Haemostasis) occurring in the wrong place, i.e...
; - Maintaining or increasing range of motion.
The FDA mandates that manuals prominently display contraindication, warnings, precautions and adverse reactions, including: no use for wearer of pacemaker; no use on vital parts, such as carotid sinus nerves, across the chest, or across the brain; caution in the use during pregnancy, menstruation, and other particular conditions that may be affected by muscle contractions; potential adverse effects include skin irritations and burns
Only FDA-certified devices can be lawfully sold in the US without medical prescription. These can be found at the corresponding FDA webpage for certified devices. The FTC has cracked down on consumer EMS devices that made unsubstantiated claims; many have been removed from the market, some have obtained FDA certification.
See also
- ElectrotherapyElectrotherapyElectrotherapy is the use of electrical energy as a medical treatment In medicine, the term electrotherapy can apply to a variety of treatments, including the use of electrical devices such as deep brain stimulators for neurological disease. The term has also been applied specifically to the use of...
- Electrotherapy (cosmetic)Electrotherapy (cosmetic)Cosmetic electrotherapy is a range of beauty treatments that uses low electric currents passed through the skin to produce several therapeutic effects, such as muscle toning in the body, and micro-lifting of the face...
- Skeletal muscleSkeletal muscleSkeletal muscle is a form of striated muscle tissue existing under control of the somatic nervous system- i.e. it is voluntarily controlled. It is one of three major muscle types, the others being cardiac and smooth muscle...
- Musculoskeletal injuryMusculoskeletal injuryMusculoskeletal injury refers to damage of muscular or skeletal systems, which is usually due to a strenuous activity. In one study, roughly 25% of approximately 6300 adults received a musculoskeletal injury of some sort within 12 months—of which 83% were activity-related...
- ScoliosisScoliosisScoliosis is a medical condition in which a person's spine is curved from side to side. Although it is a complex three-dimensional deformity, on an X-ray, viewed from the rear, the spine of an individual with scoliosis may look more like an "S" or a "C" than a straight line...
- Locked-in syndromeLocked-In syndromeLocked-in syndrome is a condition in which a patient is aware and awake but cannot move or communicate verbally due to complete paralysis of nearly all voluntary muscles in the body except for the eyes. Total locked-in syndrome is a version of locked-in syndrome where the eyes are paralyzed as...
External links
- Collection of Extensive Bibliography and Abstracts
- Seattle Times - opinion piece on personal electronic muscle stimulation belts
- John Porcari @ University of Wisconsin–La Crosse next plans to study ems buttocks and thigh toners
- EMS Digest - A guide to electrostimulation theory and practice inspired by a workshop by Gianpaolo Boschetti
- Casting new energy onto broken limbs