An electric muscle stimulator (often referred to as an EMS machine or unit) is an electronic device used to deliver electrical impulses to the body, in order to make the muscles contract. Impulses are sent from the device to a series of electrodes (usually adhesive pads), which are placed on the skin, over the muscles being targeted.

• Recovery – increase blood flow and remove lactic acid
• Training – power, endurance, strength, size, etc.
• Rehabilitation – building and strengthening muscle
• Prevention – warmup before exercise
• Appearance – muscle toning