Periodically one sees an advertisement for an electrical device that supposedly builds muscles, strength, or helps someone to lose weight. All without a minute of exercise. Without a doubt, some types of electrical stimulation are beneficial, however; the resultant gains in fitness, the muscles and strength are miniscule. The medically approved electrical stimulation devices used in a physical therapy setting or after a surgery to control pain work well. The tens unit comes immediately to mind. But it is not a fitness device and was never meant to be either.
The repeated low intensity shocks produced by these electrical devices can force rapid contractions of the muscles. This repeated stimulation does cause a certain amount of growth in the muscle fibers, meaning more strength potential, but even the best of these devices, as used in the medical field, can do only so much. They help by partially staving off muscle atrophy during the rehabilitation. Fitness exercise is much more efficient.
In order to gain muscle size, strength, and to burn enough calories to lose weight, exercise is a critical part of the equation. Without exercise, these devices are practically useless, especially the ones seen on TV.
One popular, regularly advertised, model found that the stimulation of the major muscles of the abdomen, arms, and legs for up to 45 minutes, three times a week for a full two months produced no significant changes in the participants strength levels, body fat ratio to lean muscle mass, weight , or their overall appearance.
The recommendation from most astute observers is to regularly exercise and follow a sound nutritious diet because getting stronger, bigger, and losing weight does not come with an electrical machine. You actually have to be active and pay attention to what you eat and drink. Fitness and strength do not come easily.