Increasing Involuntary Torque Production by Using TENS.

The opinions and assertions contained herein are the private views of the authors, and are not to be construed as official or as reflecting the views of the Departments of the Army, Navy, or Defense. The purpose of this study was to evaluate the effects of low-amplitude electrical stimulation (ES) on maximal tolerable ES and involuntary torque production of the quadriceps femoris muscle. Seventeen healthy volunteers (11 male, 6 female) aged 19-35 years (mean, 25.1 years) completed the study. Both quadriceps femoris muscle groups received maximal tolerated ES in all subjects. One limb was treated with 10 minutes of low-amplitude ES prior to application of the maximal tolerated ES, while the opposite limb did not receive the low-amplitude ES. Analysis of the data revealed significantly (p < 0.01) greater torque generation and current tolerated when the maximal tolerated ES was delivered following the low-amplitude ES. The clinical implication is that if ES is to be used to increase muscular strength, a low-amplitude current delivered prior to maximal tolerable current delivery allows greater involuntary torque production. J Orthop Sports Phys Ther 1990;12(3):101-104.