Best Electric Muscle stimulators – Top Ten 2018 These won’t break the bank and most have not only TENS capabilities but also EMS  Electric muscle stimulation (EMS) is a proven technique to strengthen muscles, rehab muscles, prevent muscle atrophy and relieve pain. EMS targets motor nerves and TENS targets sensory nerves. The Tens (transcutaneous electrical nerve stimulation) unit is a nerve stimulator that relieves pain. It is sometimes confused with EMS….