Posttetanic potentiation in knee extensors after high-frequency submaximal percutaneous electrical stimulation

Context: The understanding of posttetanic potentiation (PTP) in human muscles induced by percutaneous electrical stimulation (PES) is important for effective application of electrical stimulation in rehabilitation. Objective: To examine the effect of 7-second high-frequency (100-Hz) submaximal (25% of maximal voluntary contraction force) direct PES on contractile characteristics of the knee-extensor (KE) muscles. Design: Single-group repeated measures. Setting: Kinesiology laboratory. Subjects: 13 healthy men age 18-27 years. Measurement: Peak force (PF), maximal rates of force development (RFD) and relaxation (RR) of supramaximal twitch, and PF of doublet and 10-Hz tetanic contractions before and after direct tetanic PES. Results: A significant potentiation of twitch, doublet, and 10-Hz tetanic-contraction PF has been observed at 1-5 minutes posttetanic. Twitch RFD and RR were markedly potentiated throughout the 10-minute posttetanic period. Conclusions: A brief high-frequency submaximal tetanic PES induces PTP in KE muscles associated with small increase at 1-5 minutes.