Serum creatine kinase, CK‐MB, and perceived soreness following eccentric exercise in oral contraceptive users

Abstract

Estrogen ingestion has been suggested as a protective mechanism of muscle membrane integrity against an exercise‐induced muscle inflammatory response. Serum creatine kinase (CK) concentration and the heart muscle isoenzyme CK‐MB have been used as diagnostic markers of muscle disruption following exercise. The purpose of this study was to determine the difference in serum CK, CK‐MB, and perceived soreness following exercise‐induced muscle disruption in females taking an oral contraceptive (OC) and those not. Subjects included sixteen females, eight in the experimental group and eight in the control group. Estrogen concentration, determined pre‐exercise, was 181 ± 45 pg/ml for the OC group and 124 ± 25 pg/ml for the controls, respectively. Subjects participated in an eccentric hamstring exercise which consisted of six sets of ten repetitions at 110% of concentric 1RM. Serum CK, CK‐MB concentration and perceived soreness were assessed pre‐exercise and immediately, 24,48,72 and 96 hours post‐exercise. Serum CK concentration increased significantly (p < .05) in the period post‐exercise 17‐fold in the OC group and 59‐fold in the control group. Serum CK‐MB concentration increased 3‐fold in the OC group and 80‐fold in the control group in the same period. Perceived soreness was significantly (p < .05) different between groups for hamstring soreness. The data indicate that a controlled concentration of serum estrogen supplied to the OC group may effectively reduce the degree of muscle membrane permeability or disruption as indicated by the reduced magnitude of the circulating concentration of the CK, CK‐MB enzyme difference between the estrogen and non‐estrogen groups, respectively, following exercise‐induced muscle soreness.

Notes

Corresponding author. Tel.: [phone]. Fax: [phone]. E‐mail: hayward1@ jeflin.tju.edu.

Present address: Department of Physiology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107.

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Notes on contributors

Reid Hayward

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