EMS (electrical muscle stimulation)

EMS, short for electrical muscle stimulation, sends an electrical current through pads placed on the skin over a muscle, causing the muscle fibers underneath to contract involuntarily. This is a different goal from TENS, which targets nerves to interrupt pain signals, even though the two technologies often live in the same device category and sometimes even the same unit with switchable modes.

People use EMS for a few different purposes at home, including trying to keep a muscle active during downtime from injury, adding a light contraction based warm-up before activity, or simply as part of a broader muscle recovery and maintenance routine. The sensation ranges from a mild twitch at low intensity to a strong, visible contraction at higher settings, and most units let you choose from several preset programs aimed at different goals.

As with TENS, pad placement following the manufacturer's diagram matters for getting the current to the intended muscle, and intensity should be increased gradually from session to session rather than maxed out immediately. EMS devices are not appropriate for people with a pacemaker or other implanted electrical device, are generally avoided during pregnancy, and anyone using one for a specific injury or medical purpose rather than general muscle maintenance should get guidance from a doctor or physical therapist first.