Relationship between body size and skeletal age with muscle damage in young soccer players.

This study verified the relationship between body size and skeletal age (SA) with the behavior of blood markers of muscle damage and delayed onset muscle soreness (DOMS) after a soccer match in the U-13 and U-15 categories. The sample consisted of 28 soccer players in the U-13 and 16 in the U-15 categories. Creatine kinase (CK), lactate dehydrogenase (LDH), and DOMS were evaluated up to 72h after the match. Muscle damage was elevated at 0h in U-13, and from 0h to 24h in U-15. DOMS increased from 0h to 72h in U-13 and from 0h to 48h in U-15. Significant associations of SA and fat-free mass (FFM) with muscle damage markers and DOMS were observed only in U-13, specifically at time 0h, when SA explained 56% of CK and 48% of DOMS and FFM explained 48% of DOMS. Concluded that in the U-13 category, higher SA is significantly associated with muscle damage markers, and increase in FFM is associated with muscle damage markers and DOMS. Furthermore, U-13 players need 24h to recover pre-match muscle damage markers and more than 72h to recover DOMS. In contrast, the U-15 category needs 48h to recover muscle damage markers and 72h to recover DOMS.