Research Repott Effect of Variation in the Burst and Carrier Frequency Modes of Neuromuscular Electrical Stimulation on Pain Perception of Healthy Subjects

The purpose of this study was to aplore the effkct of various combinations of burst and canier frequencies of neuromuscular electrical stimulation (NMES) on subjects ' perception of pain intensity associated with induction of high intensity muscle contractions. Twenty-seven healthy volunteers completed the study. After the initial test session, all subjects were treated in three additional sessions with nine combinations of burst frequencies (50, 70, and 90 bursts per second [bps]) and canier frequencies (2,500, 5,000, and 10,000 Hz) at an NMES amplitude that produced torque equivalent to 50 % of maximal voluntary contraction of their quadriceps femoris muscle. Subjects rated each frequency combination for perceived pain intensity with a visual analog scale. The combinations of burst frequencies (50, 70, and YO bps) and carrier frequencies (2,500 and 5,000 Hz) do not dijer from each other in perceived pain intensity but do dzffer signiJcantly in perceived pain from the combinations of burst frequencies at the cam'erfre-quency of 10,000 Hz. Thw; the clinician may have to try dtfferent stimulus com-binations on patients at d~fferent cuwent training levels to obtain the least indi-vidually perceived pain. [Rooney JG, Currier DP, Nitz AJ. Effect of variation in the burst and canierfiequency modes of neuromuscular electrical stimulation on pain perception of healthy subjects Phys Thm 1992; 72:800409.