Comparison of high- and low-frequency muscle stimulators.
Electrical stimulation of the quadriceps muscle with a high-frequency since wave stimulator (Electro-Stim 180) and a low-frequency rectangular wave stimulator (Respond II) was compared in 15 physiotherapists. The maximal tolerable stimulation intensity was given for 30 stimulation periods, and the isometric torque produced was measured on a Cybex dynamometer. Maximal voluntary isometric contractions were recorded immediately before and after the stimulation sessions and showed a significant reduction after stimulation, with no difference between the two stimulators. There was no significant difference between the stimulators in the amount of torque produced. The torque during stimulation with Electro-Stim 180 showed a larger variability than with Respond. With both stimulators there was a decrease in the torque produced with an increase in number of contractions. There was no qualitative or quantitative difference between the two stimulators in the perceived discomfort. The low-frequency stimulator has a theoretical advantage because of its constant current principle and more constant stimulation effect.
Grimby
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G
Department of Rehabilitation Medicine, Gothenburg University, Sahlgrenska Hospital, Göteborg, Sweden.
Wigerstad-Lossing
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I
D000328:Adult; D004558:Electric Stimulation / Q000379:methods*; D005260:Female; D006801:Humans; D007537:Isometric Contraction; D008875:Middle Aged; D009132:Muscles