Pad placement is very important for effective EMS training. Understanding a couple of principles will help with pad positioning for any muscle. The main points to keep in mind are:
- Position relative to the muscle anatomy
- Direction between pads
- Size of pads
- Polarity in my opinion, and that of several respected researchers, is not important.
One pad goes on the belly of the muscle. This is also called the active pad, and the belly of the muscle coincides with the motor point, i.e. the point where the innervation arrives into the muscle. For example, on the vastus lateralis, i.e. the outside part of the quadriceps, the belly is the bulging in your muscle, several inches away from your knee.
The other pad, called the inactive pad, goes on the proximal end of the muscle. This is the side of the muscle closer to its innervations, i.e. closer to your head. You want the pad to remain on the fleshy part of the muscle; you don’t want this pad on the tendon, it’s better to err on the side of the muscle. For the outside quad, this is a couple of inches below the groin line, on the outside part of your thigh. To understand these positions flex your muscle and use an anatomy chart .
It’s up to you whether to use standard one-input pads, or double-input pads. There are pros and cons on the use of both: double-input pads are faster to apply, and may save you money; single input pads can be positioned more precisely on the muscle you want to stimulate.
The imaginary line connecting the center of one pad to the center of the other pad has to follow more or less the direction of the muscle fibers. This is, generally speaking, the direction along which a muscle does its pulling. If the current closes its circuit along many innervations and fibers, the current will encounter less resistance in its path, and you will obtain a stronger contraction.
One school of thought advocates pads as large as they can fit in a particular body area: this helps distribute current into the muscle and help obtain a higher comfort level. The other school of thought recommends a smaller pad on the belly of the muscle, to help concentrate the current and go deeper into the muscle. However, the depth improvement may be marginal and it’s best to see what works for you.
Most pad placement pictures were created for the physiotherapist community, which sometimes uses protocols that give a stronger jolt in one direction. However, the current generated by modern EMS devices like the Globus Premium Sport and Fitness is alternate and symmetrical: by definition pads become alternatively positive and negative. To convince yourself, pause your EMS session in the middle of it, switch the leads, and then resume: no difference in contraction.
The ideas expressed in this article reflect the opinions of the author, and should not be construed as prescription of medical or therapeutic nature by Globus Sport & Health Technologies. (C) 2008 Globus Sport and Health Technologies LLC.