Muscular pain mechanisms: Brief review with special consideration of delayed-onset muscle soreness

Abstract

Muscular pain is quite common, but its mechanisms remain poorly understood. A number of experimental muscular pain models are reviewed herein, with emphasis on delayed-onset muscle soreness (DOMS). DOMS was selected for more detailed review because factors other than inflammation seem to be involved in clinically common muscle pain, and DOMS after lengthening contraction (LC) seems to involve such aspects. The discussion on the methodology of measuring muscle pain with transcutaneous pressure stimulation in humans and awake animals is reviewed; and then studies that have shown the existence of mechanical hyperalgesia in DOMS model animals produced by LC and elongation of the hyperalgesic period (for 5 days) in aged animals (130 weeks old) are introduced. In addition, the response characteristics of thin-fiber receptors and their roles in cardiorespiratory control during exercise and pain are reviewed. In addition, increased sensitivity of thin-fiber receptors to mechanical stimulation in hyperalgesic muscle after LC is discussed. Finally, a future direction for research using the DOMS model is proposed.