Association Between Collision Exposure and Post-Match Physiological Recovery Markers in Rugby Union Players: A Systematic Review

Background: Collision exposure during rugby union matches may influence post-match fatigue and recovery. However, direct evidence linking quantified match-related collision exposure to post-match recovery outcomes is limited. Objective: To systematically review associations between match-related collision exposure and post-match recovery outcomes in rugby union players and distinguish direct evidence from indirect or contextual evidence within the broader review framework. Methods: This review, registered on the Open Science Framework (OSF), followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement. PubMed and Scopus were searched (final search: 5 August 2026), with PubMed Central used for full-text retrieval. Studies of rugby union players were eligible, and the direct-evidence studies were all match-based studies in male players from professional or elite amateur settings. Among 605 records identified, 11 studies were retained within the review framework: 4 as direct evidence and 7 as indirect or contextual evidence. Owing to differences in collision exposure definitions, biomarkers, post-match assessment times, and effect measures, evidence was synthesized narratively according to the Synthesis Without Meta-analysis guideline. Results: Four match-based studies (79 enrolled players in total) provided direct evidence for the review question. Three examined biochemical markers associated with muscle damage, specifically creatine kinase, myoglobin, and interstitial creatine kinase, but they differed in collision metrics, specimen types, and post-match sampling windows, which ranged from 30–45 min to 24 and 40 h. Across these studies, higher collision exposure was generally associated with greater post-match perturbation in these muscle-damage-related biochemical responses, although the clearest reported association in Jones et al. was limited to backs and the statistical detail available from Smart et al. was comparatively limited. One small study suggested that greater collision frequency was associated with poorer post-match sleep architecture; however, this finding should be interpreted as preliminary single-study evidence for a recovery-related outcome rather than an established physiological trend. Direct evidence regarding neuromuscular fatigue was insufficient. One indirect study reported increased post-match resting metabolic rate but did not examine its association with quantified collision exposure. Conclusions: Limited direct evidence links collision exposure to post-match recovery-related outcomes. The strongest signal concerns muscle-damage-associated biochemical markers, but this evidence is based on only three heterogeneous studies with limited cross-study comparability. Evidence concerning sleep architecture remains preliminary and is currently based on a single small study. These findings are correlational. Hence, future match-based studies should separate collision exposure from other workload measures and assess recovery-related outcomes across domains at standardized post-match time points.