Exploring the contextual relationships between match day load and recovery biomarkers in professional soccer players

Abstract

Background: This study examined the relationship between match-day (MD) load and contextual factors on recovery biomarkers in professional soccer players across the 2024/2025 competitive season. Materials and Methods: Twenty-six male professional soccer players provided blood samples following 38 competitive matches. High-sensitivity C-Reactive Protein (hs-CRP), Free-Oxygen Radicals Test (FORT), Free-Oxygen Radicals Defence Test (FORD) and Oxidative Stress Index (OSI) were analyzed. Physical MD load was measured via a Global Positioning System (GPS). Results: Differences in High-Load vs Low-Load matches did not significantly influence post-match levels of hs-CRP, FORD, FORT or OSI. Increased high-intensity running and elevated inflammation, with non-significant moderate-to-large effects (g = 0.53–0.61) were observed. The timing of post-match biomarker testing (i.e., MD+1, MD+2, and MD+3) had a significant effect on hs-CRP (p < 0.001) and FORD (p = 0.002), although no effects were observed for FORT or OSI. There was no significant difference in any biomarker across early-, mid-, or late-season. Finally, there were no significant biomarker differences between a one-match week and a two-match week. Conclusions: The current findings challenge the use of isolated biomarker monitoring in a professional soccer setting to detect recovery responses to MD load and highlight the importance of standardizing post-match measurement timing.