Surface electromyography (EMG) is a technique that allows to study the electrical activity generated by skeletal muscles during a contraction. When we wish to perform a movement the brain send to the muscle a command which generate electrical impulses modulating the direction and the intensity of the muscular contraction. Placing some electrodes on the skin above the muscle/s of interest, it is possible to non invasively record and analyze the electrical signal generated during the contraction and reconstruct the strategies adopted by the brain to generate the movement and to maintain the specific motor task. Those information are somehow related to muscle fiber type, to individual endurance or power characteristics, to the age and, in some cases, to specific pathologies. From the last decade the study of this signal was rigorously standardized throughout the world and thanks to the use of innovative electrode montages (with linear and bidimensional multichannel architectures) new features related to muscle fiber conduction velocity, motor unit firing rate and synchronization are now available from such signals.