Background: Some scientific data have been reported the positive effects of caffeine compounds on modulating the signs of delayed onset muscle soreness. The present study was conducted to identify the effect of different doses of caffeine on some serum markers of muscular damage in male volleyball players after a single session of exhaustive exercise.

Materials and Methods: In a randomized double-blind study, 30 male volleyball players (mean age 21.47±1.45 years, fat percent 10.47±3.11% and BMI 23.15±1.26 kg.m2) were allocated into three equal groups: the supplement (6 and 9 mg.kg-1 caffeine) and placebo (6 mg.kg-1 dextrose) groups. After the supplementation, all subjects were participated in a single session of resistant weight-training (80% until exhaustion). Changes in the muscular damage indices including total serum creatine kinase and lactate dehydrogenase were determined in three phases (baseline, immediately and 24 hours after the training).

Results: The results showed that the different doses of caffeine had no significant effect on the increased levels of serum enzymes of muscular damage immediately after exercise compared to the placebo group (P≥0.05). Moreover, different doses of caffeine had no effect on the increased levels of muscle damage markers 24 hours after the exercise (P≥0.05).

Conclusion: Although the different doses of caffeine cannot significantly prevent further muscular damage, it cannot lead to the further deterioration of indirect indices of muscle damage.