Longitudinal monitoring of changes in muscle damage indices and C-reactive protein during training and competitive seasons in young professional soccer players

Introduction: soccer is the most popular sport in the world, it has attracted the attention of many experts. Therefore, the aim of this study was to monitoring muscle damage indices and C-reactive protein (CRP) during the preseason and competitive season in young professional soccer players.
Materials and Methods: The present study was a semi-experimental longitudinal study, and the subjects of this study were 25 young soccer players. Blood sampling was performed on four occasions. The assessments included creatine kinase (CK), lactate dehydrogenase (LDH), and CRP during four stages. To examine the changes and differences between the stages of blood sampling, one-way analysis of variance with repeated measures was used, and if the differences were significant, Bonferroni test was used as a post-hoc test.
Findings: findings showed that CK and CRP increased significantly from the beginning to the end of the preseason (P≤0.05), decreased significantly in the middle of the half-season, and increased significantly again at the end of the season (P≤0.05). LDH increased significantly in all three phases to the beginning of the preseason, but there was no significant difference between the three stages (P≤0.05).
Conclusion: Given the increase in CK and CRP at the end of the preseason and competitive half-season and LDH in all three phases, it seems that the end of the preseason and the end of the half-season require higher physiological demands compared to the middle of the half-season, and overtraining is likely to occur in these periods.