EMS or "muscle stimulation" is used to stimulate your muscles and
cause a muscular contraction. This machine can make your muscles contract without
you voluntarily trying to contract them.
Physical therapists often use EMS plus strengthening exercises, to help you
strengthen your muscles after an injury. EMS is not very helpful in building
strength on its own.
EMS may also be used to re-train muscles how to work after having a nerve or
brain injury.