Time Course of Lipid Peroxidation, Antioxidant Markers and C-Reactive Protein Following Simulated Soccer Match-Play: A 72-h Study in Semi-Professional Players

Background/Objectives: Soccer match-play triggers muscle damage and a marked increase in reactive oxygen species production, but early and late lipid peroxidation products have rarely been tracked together with non-enzymatic antioxidants and C-reactive protein in the same players over a full 72-h window. This study characterized the recovery kinetics of oxidative damage markers (conjugated dienes, malondialdehyde) and antioxidant/defense markers (uric acid, bilirubin, reduced glutathione, gamma-glutamyl transferase), together with C-reactive protein, and explored the relationships between these markers’ recovery responses. Methods: Twelve semi-professional male soccer players completed the Loughborough Intermittent Shuttle Test (LIST). Venous blood samples were collected at Baseline, 0 h, 24 h, 48 h, and 72 h post-LIST. Repeated-measures ANOVA or the Friedman test was applied depending on normality, with Holm-adjusted pairwise comparisons against Baseline and exploratory Spearman correlations. Results: Uric acid and reduced glutathione peaked at 0 h and no longer differed significantly from baseline from 24 h and 48 h onward, respectively. CRP increased significantly at 24 h, whereas bilirubin showed only a non-significant 24-h peak. Conjugated dienes remained significantly elevated at every time point up to 72 h, whereas malondialdehyde differed significantly from baseline only at 0 h. In exploratory analyses not corrected for multiple testing, uric acid correlated with bilirubin and, on an area-under-the-curve basis, with C-reactive protein, and conjugated dienes correlated with malondialdehyde. Conclusions: The uric acid and reduced glutathione responses and the C-reactive protein response resolved within 24 to 48 h, whereas conjugated dienes remained elevated up to 72 h. These findings indicate prolonged alterations in selected circulating biomarkers rather than direct evidence of persistent muscle oxidative damage or incomplete functional recovery, and their relevance to congested fixture scheduling warrants investigation alongside performance outcomes.