Does Electrical Muscle Stimulation Hurt?

does ems hurt

No…..but it can. Not very helpful, right?

The short answer is no it doesn’t, at higher levels it can get uncomfortable but not painful. It is very rare that someone would call it painful, but the possibility exists if the intensity of the EMS is turned way up.

Most people report that being in a FITtec Whole Body Electrical Muscle Stimulation (WB-EMS) suit feels great! We have a huge percentage of people that, once they try it, are repeat, regular clients. They love the FITtec experience.

fit tech exercise

I remember my first experience going to FITtec. It was over two years ago when I put the WB-EMS suit on the first time. As I started feeling my muscles contract, while just standing there, I immediately saw how this concept can help the aging athlete (me) stay conditioned while sparing trauma to my joints. Now, I don’t want to compete in track or soccer anymore; I do want to continue to be able to hike up at tree-line. But I also just want to feel safe on the stairs of my house or run after my grandkids without blowing a knee or hurting my hip. Using WB-EMS over the past two years, I am so comfortable with the sensation that I purposefully turn the intensity way past where I started. I know what the feeling is and actually enjoy the sensation of my muscle contracting with absolutely no strain to my joints. I never thought that I’d feel this toned again (which is how muscle should feel all the time – a sure sign of vitality at any age).

So no, it doesn’t hurt, and most people love the feeling of having muscles contract intensely. And everyone loves the feeling after the workout – refreshed, with toned muscles and well-oiled joints – what a great feeling and only in 20 minutes!

It is even more effective for younger folks who want to train, condition, get fit, stay fit in less time than any other gym experience. Younger bodies will respond to the intense workout much faster than older folks. It really works for anyone who wants to feel strong, lose weight and inches.

The secret to success with a FITtec workout – really any workout – is intensity. With conventional workouts – running, lifting, etc. the intensity comes from muscle contractions that occur to protect the joints from impact that the miles or weight requires. With FITtec, the intensity comes from more current intensity to make a stronger muscular contraction. Some people can interpret that intensity as painful, but our trainers are knowledgeable in how to give you the max workout that you are conditioned for. Early on, electric intensity is lower but as you train and get more fit, you move up the intensity, so you are always challenged, and you will reach you target fitness goals safely and quickly.

Now, since this blog is about the science of EMS, I’d like to explain why the intensity feels like it does, so now we dive a little deeper into how the body is put together and how the EMS signal gets to the motor nerves. So, the answer gets longer and somewhat sciencey because you should know the why of the short answer. (This is what I call fun – nerd alert) If you are not into the science, you can stop reading here.

It comes down to how the body is put together. The nerves tell the muscles to contract. So, go ahead and contract a muscle, let’s say your quad, or your bicep, pick one. Contract it softly then hard, then as hard as you can.

Wow, you just did a lot of things inside muscles and nerves that took science hundreds of years to explain.


The science:

There is a recruitment order is which muscles fibers contract first, second and third. First to contract are the slow twitch muscles. They are responsible for basic tone and posture and easy low force and long endurance actions. Drive your car to Kansas and back. Your calf muscle pressed the accelerator pedal for hours and you could still walk after getting home. The slow twitch types of fibers have low force and high endurance.

The last fibers to contract are the fast twitch muscles which are used for high force, short durations because it takes quick response and huge energy to make them activate. (In the middle are muscle fibers that do a little of both slow and fast twitch behaviors.) Think of the fast twitch fibers like a turbo or a nitro boost to a race car, lots of power but at high energy cost that is quickly burned up, as it is fast response, fast actions such as sprints, lifting heavy weight, etc.

Remember how you contracted that muscle? At first softly, that was your slow twitch fibers, you could hold that soft contraction for a long time. Then harder, more of the mixed fibers and then hardest, the fast twitch on top of all the other fiber types. Even when you were contracting at maximum, you couldn’t hold it long, but no pain was expressed, maybe a little discomfort if you tried to hold that max contraction for any length of time. That is normal voluntary muscle contraction.

Normal contraction happens because of the kind of motor nerve types that supply the muscle. Slow twitch fibers are supplied with small diameter nerves. Fast twitch muscle fibers are supplied with large diameter nerves. Now pain fibers are also small diameter nerves, but they are located closer under the skin than the motor nerves. That arrangement makes sense because you have to know the sensations around you and the motor activators are protected deep into the body. The pain nerves do not fire when you normally contract muscles in the normal recruitment order.

This is the fascinating feature of muscles; they are extremely well designed to produce smooth, precise contractions regardless of the force required. For low force contractions, motor units with small numbers of muscle fibers are activated and activated at low frequency. For increased force production, motor nerves fire at higher frequencies and more motor nerves are activated. As force requirements increase, motor units with larger numbers of muscle fibers are recruited. (Henneman Principle)

Now, with EMS, the recruitment order is reversed. The electric signal to activate nerves comes from the skin and as well as the brain. The EMS signal works on large diameter (quicker, more easily excited) nerves first. The first motor nerves activated are the big diameter nerves that supply the fast twitch muscle fibers, then the nerves that supply the intermediate muscle fiber types and then the slow twitch muscle fibers. That means that you get the hard to fire large muscle types to contract first so your workout is bigger, deeper, more complete muscle action than you could get just by voluntary contraction.

But here comes the tricky part. The EMS signal passes right by the more superficial small diameter sensory nerves to connect with the deeper motor nerves. Since all nerves fire when electrically stimulated, when low current density stimulation is applied to the skin, the sensory nerves, which normally respond to touch, temperature and pressure, are the first to be stimulated. This causes a mild tapping or tingling sensation.

ems signal
As the workout progresses and as you get more fit, the EMS intensity can be turned up to work more muscle fibers, so as the current density is increased, more motor nerve fibers, located more deeply, that are rarely recruited, are stimulated producing bigger muscle contraction. But the EMS signal has to travel past the superficial sensory nerves and they also are more stimulated. So, you feel with the sensory nerves as well as you contract the muscles. The sensation comes from sensory nerves because of their closer proximity to the electrodes. Thus, you may ‘feel’ pain, but you are not ’in’ pain. There is no damage happening.

Further increases in the current produce rather large increases in the force of muscle contraction as muscle recruitment increases rapidly, quite disproportionate to the increase in stimulus intensity. More motor units are recruited in the area where the current is flowing. This results in both stronger and more widespread muscle contraction. Still further increases of current will eventually cause pain fibers to be stimulated, but it is not really pain. The sensory nerves convey the sensation of prickling, and tingling pain at the level of intensity that the muscles are contracting.

Therefore, with more intense EMS stimulation, there is more muscle contracting, so there is more exercise, which means more conditioning and more muscles getting stronger, fitter in less time. When you know what’s happening, you welcome that feeling because it is the sensation of getting stronger. And now you know the science behind the ability of EMS to do more muscle work in shorter time. And you know why, when I feel ‘tingling’ I know that my muscles are getting the Best workout ever!

References:

Electrotherapy explained, Principles and Practice 4th ed.
Robertson, Ward, Low, Reed, Elsevier, 2006.

Physical Principles Explained, Low, Reed, Butterworth, 1997
Biophysical Bases of Electrotherapy, Ward, Butterworth, 2006

Comparison of electro-myo stimulation to isokinetic training in increasing -power of the knee extensor mechanism *
Halback J, Straus D, J Orthop Sports Phys Ther 2:20–24 (1980)

Electrical stimulation of quadriceps femoris in an elite weight lifter: a single subject experiment.
Delitto A, Brown M, Strube MJ, Rose SJ, Lehman RC. Int J Sports Med 10:187–191 (1989)

Physiological and methodological considerations for the use of neuromuscular electrical stimulation.
Maffiuletti NA, Eur J Appl Physiol 110:223–234 (2010)

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