By Kyle Kennedy
In the strength and conditioning field, on top of lifting, jumping, and sprinting, there are myriad ways to influence performance outcomes. Many of these extras are technology-based, such as tracking velocity, forces, sleep, and recovery. One of these “extras” that I really like, but hear very little about, is electrical myostimulation, or EMS.
Most people know what EMS is, but I don’t see a lot of EMS use in the athletic community and, more specifically, in performance enhancement. I have seen it become more popular of late in high performance or CrossFit, but mainly from a recovery standpoint. I still don’t hear a lot of people talking about it from a performance/stimulus perspective. This is an area that I think holds a lot of potential.
I’ve been interested in EMS for a long time, after reading work from the Soviets, Paavo K. Komi, and coaches like Charlie Francis. It’s not like the research isn’t there—people have published it—but for several reasons, EMS is somewhat impractical in the field. If other coaches are like me, they find it difficult to isolate a single athlete in the training environment for the purpose of EMS. Since traditional machines have always been a bit cumbersome, and you can only use them on one athlete at a time, I think many coaches have written EMS off on an operational level, as opposed to a theoretical level. That being said, I think it can be a very smart investment for an elite athlete whose career tends to span over a decade when it’s all said and done. Although this article is focused on performance, most machines are quite robust and offer a multitude of benefits, for performance, recovery, and rehab.
If you’re one of those coaches who has been curious about EMS but never made the jump, I’ll highlight some of my own experiences and the questions I had about it. My personal interest in EMS admittedly came as a spinoff from my early interest in the Central Nervous System (CNS). When I first began training athletes, I very quickly understood the limitations of the CNS to deliver high-quality output. What I mean by this is that you have a finite amount of “optimal work” that you can get accomplished before the athlete fatigues and loses access to their high threshold motor units. This is the period when they’re most recovered and primed/activated. This leads to one of the questions that frequently crosses my mind.
If my nervous system is such a limiting factor, would training the system with an external stimulus be counterproductive or would it be beneficial?
The data suggests there are many uses for EMS that would drive performance through many mechanisms. According to Komi (in his book, “Strength and Power in Sport”), many studies seem to be contradictory as to the results and mechanisms of EMS. However, in 2012, Filipovic et al. did a systematic review of EMS to try and find a clear-cut response on the effectiveness of EMS.
- This scientific analysis revealed that EMS is effective for developing physical performance. After a stimulation period of 3-6 weeks, significant gains (p < 0.05) were shown in maximal strength (isometric Fmax +58.8%; dynamic Fmax +79.5%), speed strength (eccentric isokinetic Mmax +37.1%; concentric isokinetic Mmax + 41.3%; rate of force development + 74%; force impulse + 29%; vmax + 19%), and power (+67].
- As a result, the analysis reveals a significant relationship (p < 0.05) between a stimulation intensity of ≥50% maximum voluntary contraction (MVC; 63.2 ± 19.8%) and significant strength gains.
Those results seem to indicate that there is a significant benefit to the use of EMS for performance enhancement—most notably, increases in maximal strength, power, and rate of force development. The fact that performance was enhanced is clear, the mechanism by which it enhanced is not so clear. This drew me to consider whether the EMS caused adaptations by itself or whether it merely facilitated more efficient work. My main question is:
Would pre-activating motor units with electrical impulses make them more excitable from an internal stimulus? Or does the EMS cause all the adaptations on its own?
The truth is, I don’t necessarily have the data to answer these questions. You might be better asking Carl Valle, as he’s written on EMS previously (see “The Top 6 EMS Protocols for Sports Performance”). However, I can say that I’ve personally experimented with EMS and have seen positive results.
Now, before I give you my personal experiences, let me tell you that this was a very casual experiment and would hardly pass the scientific validity test. My original purpose was mainly for fun as I had just gotten my hands on a high-quality unit and was curious as to the potential outcomes. I also used this on myself, as a coach and not one of my athletes. The reason I’m sharing this is just to give some feedback to people who are curious about it but never tried it.
Operating the EMS Machine
The first thing I learned is that EMS, at least for me, is progressive. I only used EMS on my legs and I used it mainly on “explosive strength,” in conjunction with my training. This utilizes incredibly strong contractions compared to a massage or recovery setting. The first few times I used it, the contraction I could handle was limited. As I improved my tolerance to somewhere between “uncomfortable”’ and “painful,” I could handle much stronger contractions, progressively. Thus, the technology probably has limitations depending upon an athlete’s level of pain tolerance.
Also, due to its progressive nature, my guess is that best results accompany prolonged usage. Besides this, operations are fairly straightforward: Make sure you have functional equipment and a comfortable position, since your EMS session could be anywhere from 20-40 minutes long. Then, pick the program you’re looking for and use the provided guide to place the electrodes in the appropriate positions. Depending on your brand of EMS, this could be a booklet, picture, or app. At the end of the day, the modern EMS machines are pretty simple. You don’t need to know the optimal frequency or time, as this has been simplified with pre-designed programs. Just plug the machine in, and pick your program.
My Personal Protocol and Outcomes
I know that many people use EMS systems to improve recovery and pain management, but I figured a piece of technology of this magnitude would be best suited for performance. I did a dedicated squat protocol and supplemented with explosive strength on the EMS (mostly quads, as they’re easiest alone) on training days. I figured there were plenty of ways I could work on recovery, but I wasn’t sure of other ways to send impulses through my system that were equal to or stronger than a maximum voluntary contraction. From a performance standpoint, this intrigued me.
Since I didn’t intend to publish data, I never set any controls and didn’t track my data that thoroughly; I only decided to write about this later. However, after about eight weeks, I was able to PR my back squat. The reason I think the EMS contributed to this is because I am nowhere near PRing on any of my other compound lifts, and my Olympic lifting is mainly attributed to technique improvements. Between my age and my training environment, I would never have thought that I’d actually hit a lifetime PR.
My training and EMS protocol followed three main squat workouts per week (I’m not including my accessory or upper body work here). Each of the three days would start with some Olympic lifting or Olympic lifting derivatives, and then went into the squatting soon after. It was never a significant amount of Olympic lifting volume—it was more of a primer than anything.
- On my first squat day of the week, I worked up to five sets of five.
- On my second squat day of the week, I worked up to five sets of three.
- On my last squat day, I worked up to a few doubles, then three or four singles.
Essentially, I went from volume at the beginning of the week to high load at the end of the week, but used auto regulation to find my numbers. I was fairly aggressive with the numbers I wanted, but I also never forced any and never failed a rep in training.
At night on these days, I doubled up and hit a quad program of EMS on either strength or explosive strength, with about 80-90% adherence over the six to eight weeks. I personally prefer explosive strength. I felt that by repeating on the same day, I could get a greater volume of work in after my nervous system had failed. Not only did I actively progress and overload with my training, but I tried to push with the EMS as well. Not that I recommend it, but I got to the point where I wore a mouthguard to bite down on when contractions became intense. All in the name of science.
I’m telling you all this to explain that I last managed to hit a 400lb back squat before my daughter was born, derailing my training once again. While it’s been almost 10 years since my football career, the EMS and training combination allowed me to hit numbers I thought were no longer within my grasp, due to my limited time and focus on training. I highly encourage you, if you have the right situation, to try experimenting with it yourself.
Although the EMS didn’t help with soreness, and I battled days of aching and tightness, I rarely had trouble increasing load by the time my body was sufficiently warmed up for the day. Between the combination of my own results and positive research, I definitely plan to continue experimenting with EMS on myself and a few of my athletes.
The Reasoning Behind My Conclusions
I’m sure there are other educators and maybe even coaches who can give better explanations of the mechanisms and outcomes involved, but I have my own guesses as to why EMS may be beneficial. I personally tend to think performance is driven more from the abilities of the nervous system than the abilities of the tissues involved, but I think EMS might possibly reconcile the two. I know I’ve personally seen compensations occurring, both in myself and in my athletes, and the inability to voluntarily activate specific muscle groups in a uniform way, during certain movements.
A clear example would be an athlete who is relatively strong, but if you asked him to do unilateral movements, he may lack the ability to activate or at least feel a strong contraction on one side vs. the other, either due to injuries or when seemingly “healthy,” if there is such a thing. For instance, asking an athlete with quad tendinopathy to do a single leg hip thrust—my guess is they won’t get much action out of the hip joint. I personally had issues with this even while operating at a high level (relative to my own maximal abilities). My belief isn’t clear, but if we’re inefficient at uniformly activating motor units and muscle fibers in training, EMS can stimulate an equal number of motor units on each limb relative to the amount of impulse being subjected to the area. Where I think this applies is probably (and remember, this is my opinion) through potentiation rather than tissue adaptation.
It is possible that the impulses can stress the local system enough to form their own adaptations, but I personally am not convinced that would be the case. My assumption, and take it for what it’s worth, is that intense uniform impulses probably make it more efficient at voluntarily activating those fibers in my own movements later on in my next training session. I personally only tested EMS in conjunction with training, not as a replacement for it, so it’s hard to say whether the EMS itself caused its own training adaptations.
As much as I feel like my training is generally guided by sound research, the contradictions and confusion with EMS make me want to continue to experiment on my own, as well. I feel that the downside has so far been minimal (or none), but the upside could be significant. I’ve already tested EMS with maximal strength and will continue to test it in more explosive ways, either with a jump test or sprint test.
If you’ve had success, or otherwise, with EMS, please share your stories and get some information out there! I’d love to hear about your experiences and keep pushing the boundaries of performance.