Single fiber electromyography (SFEMG) is a sensitive diagnostic tool for neuromuscular transmission disorders. Stimulation SFEMG is generally preferred, due to the ease of the procedure. By using this method, we investigated the extensor digitorum communis muscle in 10 healthy volunteers. Compared with the study in voluntarily activated muscle, we found a significantly lower jitter. Our results suggest that the upper normal limit for the mean jitter is 23 µsec, while it is 38 µsec for the jitter of the individual motor end plates.