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Pal, S, Chaki, B, Chattopadhyay, S, and Bandyopadhyay, A. High-intensity exercise induced oxidative stress and skeletal muscle damage in post-pubertal boys and girls: a comparative study. J Strength Cond Res 32(4): 1045-1052, 2018-The purpose of this study was to examine the sex variation in high-intensity exercise induced oxidative stress and muscle damage among 44 sedentary postpubertal boys and girls through estimation of postexercise release pattern of muscle damage markers like creatine kinase, lactate dehydrogenase (LDH), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and oxidative stress markers like extent of lipid peroxidation (thiobarbituric acid-reactive substances) and catalase activity. Muscle damage markers like creatine kinase, LDH, ALT, and AST were measured before, immediately after, and 24 and 48 hours after high-intensity incremental treadmill running. Oxidative stress markers like thiobarbituric acid-reactive substances and catalase activity were estimated before and immediately after the exercise. Lipid peroxidation and serum catalase activity increased significantly in both groups after exercise (p < 0.001) with postexercise values and percentage increase significantly higher in postpubertal boys as compared to girls (p < 0.001). Creatine kinase and LDH activity also increased significantly above pre-exercise level at 24 and 48 hours after exercise in both the sexes, (p < 0.001) with values significantly higher for boys than the girls (p < 0.001). Although ALT and AST increased significantly in both the groups after exercise, the pattern of postexercise release of these markers were found to be similar in both the groups. Accordingly, it has been concluded from the present investigation that high-intensity exercise induces significant oxidative stress and increases indices of skeletal muscle damage in both postpubertal girls and boys. However, postpubertal girls are relatively better protected from oxidative stress and muscle damage as compared to the boys of similar age and physical activity level. It is further evident that sex difference may not be apparent for all the biomarkers of muscle damage in this age group.

Background & objectives:High-intensity exercise results in oxidative stress in adult population. Impact of pubertal attainment on high-intensity exercise-induced oxidative stress in sedentary paediatric population has not been investigated in detail. The present study was conducted to investigate the extent of high-intensity exercise-induced oxidative stress in sedentary pre- and post-pubertal boys through estimation of serum thiobarbituric acid reactive substances (TBARS), total thiol content and activities of superoxide dismutase (SOD) and catalase (CAT).Methods:Sixty four sedentary pre-pubertal (n=32, age = 10.21±0.67 yr) and post-pubertal (n=32, age = 15.58±0.47 yr) boys performed incremental treadmill running exercise at 80 per cent of the age predicted maximum heart rate till volitional exhaustion. Blood sample (5 ml) was drawn from each individual before and after the exercise for estimation of oxidative stress markers.Results:Pre-exercise SOD activity and total thiol level showed significant positive relationship with age and were significantly higher in post-pubertal boys. Serum TBARS level, SOD and CAT activities increased while total thiol content decreased in both the groups following exercise. Post-exercise percentage change in TBARS, SOD activity and total thiol level was significantly higher in post-pubertal boys, and these variables had significant positive relationship with age. No significant intergroup variations were noted in CAT activity before or after exercise.Interpretation & conclusions:Extent of post-exercise oxidative stress increased significantly with attainment of puberty. However, baseline and post-exercise antioxidation status also increased significantly as a function of age with pubertal maturation allowing the post-pubertal boys to counter relatively higher oxidative stress more efficiently than their pre-pubertal counterparts. Post-exercise upregulation in CAT activity might not be influenced by age or pubertal maturation in this age group.

Objectives: High-intensity exercise induces intensity dependent leukocytosis due to increased trafficking of white blood cells in circulation and also causes red blood cell (RBC) damage and hemolysis due to osmotic and mechanical stress. The present study was aimed to investigate the high-intensity exercise-induced perturbations of hematological profile in sedentary post-pubertal boys and girls. Materials and Methods: Blood samples were collected from sedentary post-pubertal boys (n = 22, age = 16.10 ± 0.74 years) and girls (n = 22, age = 16.04 ± 0.63 years) before and immediately after exercise to assess hematological parameters such as RBC Count, hematocrit, hemoglobin concentration (Hb), total leukocyte counts, and differential count. Results: Pre- and post-exercise RBC count, Hb and hematocrit had no significant inter-group variation. Pre- and post-exercise hematocrit and Hb were significantly (P < 0.001) higher in post-pubertal boys. Leukocyte count had insignificant intergroup variation before the exercise but it increased significantly (P < 0.001) following exercise in both the groups. Monocytosis and neutrophilia were significantly (P < 0.01) higher in post-pubertal boys. Percentage change in monocyte, eosinophil and basophil did not depict significant inter-group variation while percentage increase in neutrophil was significantly (P < 0.01) higher in boys as compared to girls. Post-exercise absolute lymphocyte count as well as percentage increase in this variable was significantly (P < 0.001) higher in girls as compared to boys. Absolute eosinophil count increased significantly in both the groups but its relative count declined substantially probably due to higher rate of mobilization of lymphocyte and neutrophil. Basophil count was also perturbed following exercise. Conclusion: Gender appeared to have insignificant impact on exercise-induced perturbation in hematological profile at post-pubertal stage except for neutrophil and lymphocyte.