Electrical muscle stimulation is electrical current that affects the myo-neural junction – or the area the nerve intervates or goes into the muscle. As the electrical current is increased there will be an involuntary contraction of the muscular area being treated.
Passive exercise (contraction and movement involuntarily done while the muscle is at rest) will exercise and thereby strengthen the muscle without injuring it. The area of involvement will then heal stronger and will be much more stable.
The contraction produced by the electrical current also helps to increase the circulation in the area through exercise, also promoting healing and strengthening the area of muscles involved.