If you’ve heard of electronic stimulation, also called EMS or e-stim, then it was probably through stories of Bruce Lee, who claimed that three minutes hooked up to an e-stim device was the equivalent of doing 200 pushups.

And while Yves Gege, a physical therapist at Made 2 Move in South Carolina, says, “EMS can’t make a muscle stronger—only progressive loading can do that,” e-stim is still popular among physical therapists to help treat pain, soothe sore muscles, and speed up the recovery of injured tissues.

There are two main types of e-stim you’ll encounter: TENS (transcutaneous electrical nerve stimulation), which is thought to lessen pain in the short term by stimulating the sensory nerves—sort of like if you bang your knee on something and you rub it to make it feel better, says Gege—and NMES (neuromuscular electrical stimulation). This type of e-stim goes deep into atrophied muscles, and assists in strengthening them by helping them fire more effectively.

E-stim is also thought to help muscles recover after hard workouts, as the contractions can flush out lactic acid, according to David Geier, M.D., an orthopedic surgeon in Charleston, SC. Additionally, it’s used to combat the soreness from heavy training as well as to overcome injuries. The electrical impulses seem to make the muscles feel better, and allow them to recover faster. Geier adds, “It’s thought to bring blood flow to the area, and doing so might help an injured structure heal.”

E-stim 101

E-stim is a modality used by physical therapists and other health professionals to reduce pain and increase muscle activation. Here’s how.

The setup

A smart phone-sized unit is attached to several wired sticky pads. The pads are placed on the skin, and an electric current is run to the pads.

Rebuild

NMES is used after surgery to re-educate a muscle, says Gege. It may also expedite healing by decreasing swelling and flushing out toxins.

Survey says…

Studies have shown that e-stim can improve subjective pain and soreness, says Gege. But these studies could always be more robust.

Recover better

E-stim can also speed up recovery after tough workouts, allowing you to accumulate more volume over time while preventing injuries related to overuse.