Influence of puberty on high intensity exercise induced skeletal muscle damage and inflammatory response in sedentary boys

The present investigation examined the influence of age and pubertal transition on magnitude of muscle damage and inflammatory response following high intensity incremental treadmill running till volitional exhaustion in sixty-four sedentary prepubertal (n ​= ​32) and postpubertal (n ​= ​32) boys who were randomly recruited in the study. Muscle damage and inflammatory markers like creatine kinase (CK), lactate dehydrogenase (LDH), alanine aminotransferase (ALT), aspartate aminotranferase (AST), C-Reactive Protein (CRP) and Interleukin-6 (IL-6) were estimated before and after exercise. Serum CK, LDH, AST, ALT, CRP and IL-6 levels significantly increased after exercise in both the groups in comparison to respective pre-exercise values. Although CK, LDH, CRP and IL-6 responses were significantly higher in postpubertal boys, no intergroup variation was noted in post-exercise ALT activity. Age and body mass index (BMI) had significant positive correlation with post-exercise CK, LDH, AST, CRP, and IL-6 levels. Muscle injury and inflammation were significantly higher in postpubertal boys, suggesting a rise in these responses as a function of age and muscle mass during onset of puberty. Post-exercise release pattern of ALT was not influenced by age and puberty. Data also revealed that concentric endurance exercise did not induce extensive muscle damage and inflammation in both the groups. Drastic elevation in IL-6 level despite lower muscle damage implied that this marker was released from contracting muscle fibers independent of muscle damage and acute inflammation. The magnitude of this post-exercise IL-6 release increased as a function of age and BMI.