PLASMA CREATINE KINASE (PCK) RESPONSE OF 18- TO 30- YEAR-OLD AFRICAN-AMERICAN MEN TO ECCENTRIC EXERCISE 60

Abstract

Previous studies have indicated that baseline PCK activities of African-American men tend to be higher than those of other gender-race groups. Also, limited previous research has suggested that responses of PCK following exercise may be greater in African-American men. The purpose of this study was to describe the PCK response of a sample of African-American men to a bout of eccentric exercise. 15 African-American men (age = 25±1 yr[mean±S.E.], height = 179±2 cm, weight = 92.3±3.9 kg) each walked backwards on a treadmill at 3.0 km·h-1 down a 23% grade. (This exercise emphasizes eccentric contractions of the plantar flexor muscles.) Venous blood was sampled before, immediately (0 d) after, and 1, 2, 4 and 7 d after the exercise for determination of PCK activity(IU·L-1 at 30°C). Results are summarized in thetable. Consistent with earlier reports, these African-American men had relatively high baseline PCK values; 12 of 15 were above the upper limit of normal (130 IU·L-1) for the assay. Nevertheless, PCK responses to the eccentric exercise were similar to responses of other subjects in previous studies.