Preferential activation of muscle fibers with peripheral magnetic stimulation of the limb.

Magnetic and electric activation of limb nerve and muscle were compared in normal subjects of different age, gender, and habitus. Direct stimulation of nerve and muscle showed that activation of intramuscular nerve fibers in the arm and leg occurs at a lower threshold for magnetic stimulation than for electric stimulation. Sensory nerve fibers had a lower threshold with electric stimulation. Muscle activation and stimulus artifact with magnetic stimulation precluded reliable recording of distal sensory nerve action potential in all subjects.