TENS is used to relieve pain while EMS is for muscle growth and athletic training. It helps in relieving certain types of chronic and acute pain by stimulating the nervous tissue. Whereas, EMS is designed to treat the muscle area than the nerves and helps in reducing swelling and muscle inflation which can have a negative effect as strained muscles can pull joints out of place. To sum it up, EMS is used for therapeutic muscle stimulation and growth, and TENS is used to relieve pain symptoms. Read more to know the difference between TENS and EMS units.