Prof. J.P.N. Mishra
The quality of an EMG measurement strongly depends on a proper skin preparation and electrode positioning. The main strategy of skin preparation is stable electrode contact and low skin impedance. Most modern EMG-amplifiers are designed for skin impedance levels between 5 and 50 kOhm (between pairs of electrodes). Usually it is necessary to perform some skin preparation before the electrodes can be applied. There are no general rules for it and several possibilities to reach a good skin condition for EMG-measurements exist. Especially for beginners it will be of great value to check the quality of the chosen method by measuring the actual impedance resistance between electrodes with a regular multi-meter or specialized impedance meters. Another important consideration is the targeted test condition and exercise. If a somewhat static or slow motion movement is planned (e.g. a clinical muscle function test) and the basic analysis idea is qualitative (amplitude changes in terms of more/less), a simple alcohol cleaning may be sufficient. If very dynamic conditions with risk of movement artifacts (e.g. fast walking, running or other highly accelerated movements is planned), a very thorough preparation is imperative.
Skin preparation procedures
The following procedures may be considered as steps to prepare the electrode application:
