The purpose of this study was to investigate the effects of acute complex training (combination of plyome-trics and multi-joint resistance exercises) on muscle damage markers. Twenty-four young, healthy men were randomly assigned to one of three groups: a) Complex training group with high-intensity resistance exercise(CH, N=8, plyometrics: 100 total foot contacts; resistance exercise: 90% 1RM, 3 sets/exercise of 3 repetitions each), b) Complex training group with low-intensity resistance exercise(CL, N=8, plyometrics: 100 total foot contacts; resistance exercise: 50% 1RM, 3 sets of 3 repetitions each), and c) a control group (C=8). Creatine kinase (CK) activity, lactate dehydrogonase (LDH) activity, cortisol, testosterone and testosterone to cortisol ratio were assessed at rest, immediately post-exercise as well as 24h, 48h, 72h, and 96h of recovery. CK activity was markedly ncreased (p<.05) by 75% and 82% 24h post-exercise in CL and CH, respectively and returned to baseline thereafter. LDH activity increased in both exercise groups (60-70%) throughout recovery. Cortisol concentration increased (p<.05) throughout recovery in both groups. Testosterone concentration increased (p<.05) for as long as 72h post in CH and between 48h and 72h of recovery in CL. In conclusion, it appears that complex training produced a marked rise of muscle damage markers which may be related to a cortisol-mediated immunosuppression.