PRESENCE OF WBC, DECREASED STRENGTH, AND DELAYED SORENESS IN MUSCLE AFTER ECCENTRIC EXERCISE

The purposes of this study were to assess the presence of Tc-99m-label ed white blood cells (WBC) in exercised muscle compared with nonexerci sed muscle over time and to determine the time course of delayed onset muscle soreness (DOMS) and eccentric torque in 10 female subjects. A pretest was followed by 300 eccentric repetitions of the right quadric eps. DOMS and eccentric torque were measured at 2, 4, 20, 24, 48, and 72 h postexercise. Eccentric torque was also tested at 0 h. Radionucli de images of both quadriceps were taken at 2, 4, 20, and 24 h postexer cise. The presence of Tc-99m-WBC in the exercised muscle was significa ntly greater (P < 0.001) than in the nonexercised muscle. Eccentric to rque declined at 0 and 24 h postexercise. DOMS peaked at 24 h postexer cise. The presence of Tc-99m-WBC in the exercised muscle in the first 24 h suggests that acute inflammation occurs as a result of exercise-i nduced muscle injury. The bimodal pattern of eccentric torque supports the hypothesis that more than one mechanism is involved.