The Relationship Between Match-Play Characteristics of Elite Rugby League and Indirect Markers of Muscle Damage

Purpose: While exercise-induced muscle damage (EIMD) after rugby league match play has been well documented, the specific match actions that contribute to EIMD are unclear. Accordingly, the purpose of this study was to investigate the positional demands of elite rugby league matches and examine their relationship with subsequent EIMD. Methods: Twenty-eight performances (from 17 participants) were captured using 10-Hz global positioning systems over 4 competitive matches. Upper- and lower-body neuromuscular fatigue, creatine kinase (CK), and perceived muscle soreness were assessed 24 h before and at 12, 36, and 60 h after matches. Results: High-intensity running was moderately higher in backs (6.6 +/- 2.6 m/min) than in forwards (5.1 +/- 1.6 m/min), whereas total collisions were moderately lower (31.1 +/- 13.1 vs 54.1 +/- 37.0). Duration (r = .90, CI:.77-.96) and total (r = .86, CI:.70-.95) and high-intensity distance covered (r = .76, CI: .51-.91) were associated (P < .05) with increased CK concentration postmatch. Total collisions and repeated high-intensity efforts were associated (P < .05) with large decrements in upper-body neuromuscular performance (r = -.48, CI: -.74 to .02; r = -.49, CI: -.77 to .05, respectively), muscle soreness (r = -.68, CI: -.87 to -.10, r = -.66, CI: -.89 to .21, respectively), and CK concentration (r = .67, CI: .42-.85; r = .73, CI: .51-.87, respectively). All EIMD markers returned to baseline within 60 h. Conclusion: Match duration, high-intensity running, and collisions were associated with variations in EIMD markers, suggesting that recovery is dependent on individual match demands.