Should You Try Electrical Muscle Stimulation?

Rest and recovery are critical components of any training program. Can EMS devices soothe achy muscles faster and send you to your next workout fresh and strong?

Heading out the door? Read this article on the new Outside+ app available now on iOS devices for members! Download the app.


Fitness enthusiasts will do downright crazy things in the name of recovery. Drawing solely from personal experience, I can tell you that swapping Gatorade for cold vegetable broth after a sweaty training run is better in theory than execution; there is such a thing as too much Tiger Balm; and ice baths, if they don’t reduce inflammation, will certainly increase your level of self-pity.

So when given the opportunity to try out the Marc Pro, an electrical muscle stimulation (EMS) device, I was more than up for it. The idea of using electrical currents to jolt myself through an abbreviated recovery period was intriguing. Even if it didn’t help, I’d have another weird experiment to add to the list.

I quickly found out that the Marc Pro isn’t about shocking you into feeling better. In fact, Marc Pro differentiates itself from other units with a proprietary “dynamic decaying waveform” that sounds much gentler than what other devices offer.

Most employ static square waveforms and relatively high voltages and frequencies to generate enough muscle recruitment. A static square waveform contracts the muscle at full power, holds it at that full power, then instantly and fully releases the muscle. It’s an unnatural signal that can be harsh, and in some cases quite uncomfortable and fatiguing.

By contrast, the Marc Pro device employs a proprietary dynamic decaying waveform. This type of signal comfortably contracts muscles and then slowly releases them over a period of time. Muscle fibers are allowed to properly relax, and fluids are moved in and out of the area without causing fatigue to the muscle.


So if the Marc Pro did what it was supposed to do, I could expect to alleviate soreness and go into my next workout feeling fresh and strong.

How I Used It

I jumped in feet first. The day’s workout had included box jumps and a series of 800-meter runs, and my heel (a case of lingering plantar fasciitis) was feeling tender. With the user manual as my guide, I placed the adhesive electrodes a little higher than the center of my calves and on the bottom of my heels.

Starting at a lower setting — around 2 — I mostly felt a subtle, buzzing pulse. It was more noticeable on my left side, the one with the bum foot. As I turned the intensity knobs a little at a time, the pulsing became stronger and more defined. Once I got to around 7.1, my calf muscles were visibly contracting. Out of curiosity, I bumped up the intensity to the maximum setting of 9. The pulsing became more sharp, like a localized “pins and needles” sensation, so I lowered the dials back to 7 and hung out there for 15 minutes.

Walking around after my treatment, I did feel a difference. My calves felt less tight, like I’d just wrapped up some serious foam rolling or a yoga class heavy on downward-facing dog. And my heel pain was reduced to almost nothing.

I dedicated the next few sessions to my chronically tight hamstrings. I experimented with the placement of the electrodes, sometimes placing them on the backs of my legs, sometimes on my quads. Here, the difference was less noticeable; I felt some relief, but the tightness was still there.


I fared a bit better with a 30-minute treatment focused on my traps and mid back. A day after some heavy overhead lifting, I’d woken up achy and stiff. After unhooking myself from the Marc Pro, I was able to move more freely and dig into the trouble spots with a lacrosse ball.

All in all, the Marc Pro’s effects were positive. On a purely anecdotal level, I felt like I could recommend the device to friends, family and gym buddies. But, to better understand the science behind the Marc Pro, I went to C. Shanté Cofield, Doctor of Physical Therapy and founder of The Movement Maestro.

How It Works

According to Cofield, the Marc Pro (and EMS, in general) does a couple different things, but it won’t fix injuries or make you stronger. “It doesn’t change the tissue,” explains Cofield. So anyone using it with the hopes of toning or building muscle is better off focusing on lifting and strengthening exercises at the gym. The only exceptions are cases of significant muscle atrophy, like those experienced by post-operative patients. In those situations, a trained professional may recommend EMS as a part of rehabilitation.

But the average gym-goer like me can use EMS to aid recovery by relieving soreness. Part of the Marc Pro’s effectiveness can be explained by the “pain gate theory.” “You’re kind of tricking your brain into focusing on a different sensation,” says Cofield. “The pain gate theory states that when you have pain that’s transmitted on these slower never fibers, if you impart a stimulus of sensation at the same time that is transmitted on the faster, thicker nerve fibers, that blocks the other sensation, or ‘closes the gate,’ so you don’t feel as much pain.” This promotes muscle relaxation and reduces spasms. That being said, it won’t fix any underlying issues that may be causing pain, so anything beyond general muscle soreness should be evaluated by a doctor.

EMS can also be used to reduce swelling. (Again, only in cases that have been evaluated by a trained professional, as swelling is often a symptom of a larger problem.) “When it comes to swelling, one of the best anti-inflammatories we have is movement,” says Cofield. “Movement helps with fluid dynamics. When you get swelling in an area, the best way to get it out of there is to use muscular contraction to pump it out.” The issue is that, in most cases, a person experiencing swelling can’t perform muscle contractions for long enough to make a difference. With a electric muscle stimulation, 24 minutes of muscle contraction is totally achievable…and it can be conveniently paired with an episode of your favorite Netflix original series.

Is it Worth the Price?

The Marc Pro’s price tag is considerable. The device that I tested runs just under $650, and the more advanced model is around $950. I asked Cofield if you could get the same results with drugstore models or units available on Amazon for less than $20. Cofield noted that while cheaper models — most of which are TENS (Transcutaneous electrical nerve stimulation) units — may help with pain management, they typically won’t create the level of contraction needed to facilitate recovery. Therefore, depending on how important maximal recovery is to you, it may be worth the investment.