Effect of Modulated TENS on Muscle Activation, Oxygenation, and Pain: Searching for a Physiological Mechanism

• Published in: Journal of musculoskeletal pain 2005-01, Vol.13 (2), p.19-30
• Main Authors: Kavcic, Natasa S., Lehman, Greg H., McGill, Stuart M.
• Format: Article
• Language: English
• Subjects: hypoxia; muscle oxygenation; Musculoskeletal system; myoelectric activity; Nervous system; Pain management; Rehabilitation; Therapy; transcutaneous electrical nerve stimulation
• ISSN: 1058-2452; 2470-8593; 1540-7012; 2470-8607
• DOI: 10.1300/J094v13n02_04

Objectives: To understand the possible physiological mechanisms of a modulated transcutaneous electrical nerve stimulation [TENS] device on the reported reductions in pain using quantitative electromyography to measure muscle activation and near-infrared spectroscopy to estimate muscular oxygenation levels. Methods: All subjects self-selected the intensity of the TENS stimulation current. Electromyography, near-infrared spectroscopy and a color analog scale of pain intensity to measure reported pain levels were collected both pre- and post-treatment. For Studies 1 and 2, measures of muscle activity and self-perceived pain were taken from 51 male and female subjects. For study 3, measures of muscle oxygenation and pain scores were taken from 12 different subjects. Results: Myoelectric activation level and pain scores of painful muscles were reduced after treatment [P < 0.001] with no change in activation or pain in the control muscles. The follow-up study revealed that muscle oxygenation was significantly increased in the treatment trials when compared to the control trials [P = 0.013], while the color analog scale of pain intensity pain scores decreased [P