Effect of short term caffeine supplementation and intermittent exercise on muscle damage markers

Aim: To evaluate the effect of oral caffeine supplementation and strenuous intermittent exercise on muscle damage markers in soccer players. Materials and Methods: 15 male professional soccer players completed a placebo controlled double blind test protocol. At 45 min before exercise, participants ingested 5.5 mg; kg-1 body mass of caffeine (CAF, n=8) or cellulose (CEL, n=7). The exercise was 2 trials of 6 sets of 10 sprints (20 m each) with 10 s recovery time between sprints, 2 min between sets and 15 min between trials. Blood samples were collected before (PRE), 24, 48 and 72 h after exercise. Serum activity of creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransaminase (AST), and alanine aminotrasaminase (ALT) were quantified. Results: Serum enzyme activity was enhanced by exercise in both groups, without a synergistic effect of caffeine. Conclusion: Our results suggest muscle damage markers increases after physical activities, but caffeine supplementation (5.5 mg; kg-1 body mass) has no influence upon serum enzymes reflective of muscle integrity and damage.