Extraterritorial motor unit action potentials

Summary form only given. Extraterritorial motor unit action potentials (EMUAP) were recorded in different human muscles: at low muscle activity by skin electrodes and penetrating electrodes and at high muscle activity by averaging the interferent EMG triggered by single motor unit impulses recorded by a selective electrode. Two types of selective `branched´ electrodes were constructed and used: superficial and subcutaneous wire electrodes. The amplitude and shape of the EMUAP were described at different radial and axial distances and in muscles differing in morphology. The extraterritorial potential field was constructed for some motor units. Considering the EMUAP in different muscles as a sum of single muscle fiber potentials at long radial distances resulted in the explanation of the dependence of the EMUAP shape on several factors. An explanation was developed for the shape of the M-potentials in different muscles, the H-reflex, and the T-reflex potentials. Some conclusions were drawn concerning the methods for recording these potentials