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.