Determining the Relationship Between Internal Load Markers and Noncontact Injuries in Young Elite Soccer Players

Purpose: To examine the association and predictive ability of internal load markers with regard to noncontact injuries in young elite soccer players.

Methods: Twenty-two soccer players (18.6 [0.6] y) who competed in the Spanish U19 League participated in the study. During a full season, noncontact injuries were recorded and, using session rating of perceived exertion, internal weekly load (sum of load of all training sessions and matches for each week) and acute:chronic workload ratio (typically, acute = current week and chronic = rolling 4-wk average) were calculated. A generalized estimating equation analysis was used to examine the association of weekly and acute:chronic load-ratio markers with a noncontact injury in the subsequent week. Load variables were also analyzed for predictive ability with receiver operating characteristic curve and area under the curve.

Results: No association was found for weekly load (odds ratio = 1.00; 90% confidence interval, 0.99-1.00) and acute:chronic load ratio (odds ratio = 0.16; 90% confidence interval, 0.01-1.84) with respect to injury occurrence. In addition, the analyzed load markers showed poor ability to predict injury occurrence (area under the curve < .50).

Conclusions: The results of this study suggest that internal load markers are not associated with noncontact injuries in young soccer players and present poor predictive capacity with regard to the latter.