Does it hurt? Your first Compex session
What you will feel
It is your first electrical stimulation session. You turn up the intensity, the thigh starts to tingle, then to tighten on its own. At some point you think: this is strange, is it normal? Yes, it is normal. And it is better to know in advance what you are going to feel: that is what will let you raise the intensity without hesitating, and so make your muscle really work.
First, tingling under the electrodes. Then, as you go up, a feeling of tightening: the muscle contracts without you deciding it. You see the thigh harden, sometimes the kneecap lift slightly. It holds for a few seconds, releases, starts again.
At an effective intensity, it is not painful in the sense of an injury. It is uncomfortable, a strong contraction, a little strange because it does not come from you. The specialists say it plainly: at the dose that strengthens the muscle, stimulation is always uncomfortable.2 The device is doing its job.
Why intensity is everything
Researchers stimulated both legs of the same people for eight weeks: one leg at the maximum bearable intensity, the other at half. Result: strength gains followed intensity almost step for step, the stronger the contraction, the more the muscle strengthened. Conversely, a comfortable session is a session that strengthens almost nothing.1
Think of it like strength training: lifting a bottle of water a hundred times will not make you stronger. The muscle has to be truly loaded. Electrical stimulation follows the same logic, except that the load is the intensity you accept.
That is why your physiotherapist talks about “maximum tolerated intensity”. It does not mean hurting yourself. It means going up to the strongest contraction you agree to hold, session after session, and you will see that this limit moves quickly.
What makes the session easier to bear
Not everything depends on your courage. Four things really change the sensation:
The skin
Wash it with soap and water before placing the electrodes, and dry it well. No alcohol: it dries the skin and increases resistance, and therefore the tingling.2
The electrodes
Well stuck, over their whole surface, on the fleshy part of the muscle. An electrode that lifts at one corner stings. Large electrodes spread the current and are more comfortable than small ones.3
The ramp-up
Do not go for yesterday’s intensity from the first contraction. Go up notch by notch during the first contractions, let the muscle “take”, then go and find the limit.
Your hand on the button
You are the one turning it up. Nobody imposes an intensity on you. That changes everything in your head, and it is what the specialists recommend: once you understand the device, you are the one in control.2
What is normal, and what is not
Normal: tingling, a strong contraction, redness under the electrodes that fades within 10 to 20 minutes after the session, a slight tiredness in the muscle.
Not normal (stop and talk about it): a localised burning sensation under an electrode, pain in the joint itself (not in the muscle), redness that persists. And never start a new session while the skin is still red from the previous one.4
And one simple rule: never place electrodes on skin numbed by cold. If you have just done a cryocompression session, wait for the skin to warm up and for sensation to return. Your sensation is your safety.
What to remember
- Discomfort is not a problem: it is the sign that the muscle is really working.
- Intensity makes the result. Go up to the strongest contraction you accept, at every session.
- Clean, dry skin, large and well-stuck electrodes, a gradual ramp-up, and the control in your hands.
The first session surprises you. By the third, you are looking for the limit yourself.
Compex at home: how Kolde rental works
Kolde rents the Compex® muscle stimulator and delivers it to your home, with the electrodes and a hands-on walkthrough of the device, so that your first session is not a guessing game. Your surgeon or physiotherapist sets the protocol, you follow it between your sessions. The intensity you accept is the one setting that changes what the session gives you1.
Sources
-
Effects of training intensity in electromyostimulation on human skeletal muscle. European Journal of Applied Physiology. 2018.
Natsume T, Ozaki H, Kakigi R, Kobayashi H, Naito H.
DOI 10.1007/s00421-018-3866-3 · PMID 29679248 -
Who's afraid of electrical stimulation? Let's revisit the application of NMES at the knee. Journal of Orthopaedic & Sports Physical Therapy. 2024.
Arhos EK, Ito N, Hunter-Giordano A, Nolan TP Jr, Snyder-Mackler L, Grävare Silbernagel K.
DOI 10.2519/jospt.2023.12028 · PMID 37904496 -
Effects of electrode size and placement on comfort and efficiency during low-intensity neuromuscular electrical stimulation of quadriceps, hamstrings and gluteal muscles. BMC Sports Science, Medicine and Rehabilitation. 2022.
Flodin J, Juthberg R, Ackermann PW.
DOI 10.1186/s13102-022-00403-7 · PMID 35034633 - Compex user manual: precautions for use and skin care. DJO Global / Enovis.
This article is for information only. It does not replace the advice of your surgeon, doctor or physiotherapist. Always follow the recommendations of your medical team and the contraindications listed in the device’s instructions for use.