Objective: To investigate the association of a novel post-match muscle pain map, named Muscle Pain Code (MPC), with the risk of subsequent time-loss muscle injury in a cohort of professional football (soccer) players.
Methods: The MPC classifies pain in four codes: code 0, 'no pain;' code 1, 'generalized muscle pain;' code 2, 'diffused site muscle pain;' and code 3, 'specific site muscle pain.' Over four consecutive seasons, MPC was collected on the second post-match day and players were followed for occurrence of time-loss muscle injury over the next five days. Players exposed to at least 45 minutes in two consecutive matches within seven days were included as cases for analysis.
Results: Eighty players participated in the study. Of 1,656 cases analyzed, 229 resulted in time-loss muscle injuries. Only 2% of cases with codes 0 and 1 resulted in time-loss muscle injuries. Conversely, 63% and 78% of codes 2 and 3 were followed by time-loss muscle injuries, respectively. Compared with the reference scenario (i.e. code 0 on MPC), the risk of subsequent time-loss muscle injury was significantly higher when players recorded code 2 (odds ratio, 4.29; 95%CI, 3.62 to 4.96) or code 3 (odds ratio, 5.01; 95%CI, 4.05 to 5.98) on MPC, but not when they recorded code 1 (odds ratio = -0.27; 95%CI, 1.05 to 0.56).
Conclusions: Players experiencing well-outlined pain area on the second post-match day were more likely to incur a time-loss muscle injury in the subsequent days compared to those experiencing spreading pain or no pain.
Keywords: Injury prevention; injury prediction; injury risk; pain measurement; soccer.