The Effect of One Session of Muscle Soreness-Inducing Weight Lifting Exercise on WBC Count, Serum Creatine Kinase, and Plasma Volume

The purpose of this study was to assess white blood cell (WBC) count, serum creatine kinase (CK), and plasma volume (PV) changes following a single session of soreness-inducing exercise. Sixteen untrained males, aged 18 to 38 years, were exercised at 80% of one repetition maximum until failure for three sets on seven different weight lifting resistive machines. Measurements were done prior to and up to 84 hours postexercise on: a) delayed onset muscle soreness (DOMS), utilizing a four-point pain scale on seven muscles; b) CK; c) WBC count; and d) PV change, indirectly assessed by hematocrit and hemoglobin. One session of weight lifting exercise was found to produce significant postexercise PV elevations, with the peak change occurring at 36 hours (8.9%, p < .05). Significant elevations in WBC count were found 12 hours postexercise (7900 cells/mul, p < .05) when corrections were made for PV increases. In addition, DOMS and CK were significantly increased postexercise, with the highest levels occurring at 36 hours (9/21 pain scale units, p < .05) and 84 hours (5756 IU/L, p < .001). These results suggest that one session involving high intensity weight lifting exercise may induce muscle soreness and elevate WBC count, CK, and plasma volume. The aggressive initiation of a fitness program can trigger delayed muscle discomfort, a possible inflammatory process, and dilate blood parameters that physical therapists may be monitoring. J Orthop Sports Phys Ther 1991;13(6):316-321.