Although Transcutaneous Electrical Nerve Stimulation (TENS) has become a popular modality in pain management over the past 20 yr, there is still debate over its mechanisms of action and the precise relevance of stimulation parameters to its hypoalgesic effects. Thus, confusion still surrounds the selection of optimal stimulation parameters. Two separate studies (total n = 88) were carried out to investigate the effect of four combinations of TENS pulse durations (50 microseconds & 200 microseconds) and frequencies (4 Hz and 110 Hz) on nerve conduction in the human superficial radial nerve and on Mechanical Pain Threshold (MPT) within the associated sensory distribution of the nerve over the dorsum of the hand. Results showed that application of one combination of TENS parameters (110 Hz, 200 microseconds) directly over the course of the nerve produced a significant increase in both peripheral nerve conduction latency (P