درخت حوزه‌های تخصصی

Purpose: Unusual or intense exercise causes minor damage (microtrauma) to muscle fibers. It is thought that this damage is accompanied by the release of certain enzymes into the blood serum. The aim of the present study was to investigate the effect of resistance training and retraining on the enzymes creatine kinase, lactate dehydrogenase, and aspartate aminotransferase in inactive young boys. Method: Twenty-four healthy inactive young boys volunteered for the present study and were randomly divided into two groups of 10. The exercise protocol consisted of five stations of biceps and shoulders with a barbell, squats, chest presses, and forearm presses. Each movement consisted of three sets of 12 repetitions. The exercise intensity was 75% of one repetition maximum. Serum levels of the enzymes creatine kinase, lactate dehydrogenase, and aspartate aminotransferase were measured before the activity and at intervals of 1 and 48 hours thereafter. For data analysis, repeated measures analysis of variance and independent t-test were used at a significance level of p≥0.05. Results: The results of the present study showed that the levels of creatine kinase, lactate dehydrogenase, and aspartate aminotransferase enzymes increased in both resistance training and resistance retraining groups compared to the pre-test at time intervals of 1, and 48. No differences were observed in serum levels of creatine kinase, lactate dehydrogenase, and aspartate aminotransferase between the two groups during and after retraining (p>0.05). Conclusion: Retraining may not be a significant variable affecting recovery after muscle injury. However, more research is needed in this area.

Purpose: Vigorous physical exercise causes notable alterations in the circulatory system, affecting stress hormones and plasma proteins. Cortisol serves as a primary glucocorticoid hormone, while albumin, globulin, and hemoglobin function as important carrier proteins. However, how cortisol levels after exercise interact with these proteins is not well understood. This research aimed to explore the association between serum cortisol and the levels of albumin, globulin, and hemoglobin following a single session of intense aerobic exercise in young male runners. Method: Twelve healthy young male runners (average age 21.38 ± 0.95 years; VO₂max 50.81 ± 2.35 ml/kg/min) completed a 15-minute Balke treadmill test. Blood samples were collected before exercise, immediately after, and three hours post-exercise (recovery) to assess serum cortisol, albumin, globulin, and hemoglobin concentrations. Hematocrit measurements were used to adjust for changes in plasma volume. Statistical analysis involved one-way repeated measures ANOVA with Tukey’s post hoc test and Pearson correlation. Results: Immediately after exercise, there were significant increases in cortisol (61.4%), albumin (7.5%), globulin (10.5%), and hemoglobin (10.5%) (p<0.05). After three hours of recovery, cortisol, albumin, and hemoglobin levels returned to baseline, whereas globulin remained significantly elevated (p<0.05). No significant correlations were detected between cortisol changes and any of the carrier proteins at any time point (p>0.05). Conclusion: A single session of intense aerobic exercise markedly raises serum cortisol and key carrier proteins in young runners. The absence of correlation between cortisol and these proteins suggests that their immediate post-exercise increases are likely driven by factors other than cortisol fluctuations, such as hemoconcentration and changes in hydrostatic pressure, rather than direct hormonal stimulation.