Some people try, and you technically can make a muscle contract by placing the pads correctly, but there’s another choice. An electrotherapy device known as an Electric Muscle Stimulation, or EMS unit, would likely give you better results. EMS machines use electrical impulses to make your muscles contract. They help reduce muscle inflammation, spasms, and edema, the most common causes of muscle pain. EMS units stimulate the muscle themselves, while a TENS unit stimulates nerves. If you’re unsure whether your pain is caused by a problem with a muscle or a joint, be sure to talk to your doctor.