لیلا فصیحی

The phenomena of fatigue of voluntary muscular effort is intricate and multidimensional in the field of sports sciences. The causes and effects of exercise-induced fatigue have been extensively studied, but the central nervous system's (CNS) involvement in this process is still unclear. In order to understand CNS fatigue after physical activity, the current review will examine changes in neurotransmitter function during exercise. Using primary sources such scientific journals and websites, a consensus and critical evaluation were carried out in order to accomplish this goal. For a number of neurotransmitters, including dopamine and serotonin (5-HT; 5-hydroxytryptamine), hypotheses have been established. The most well-known one is a rise in serotonin levels throughout the brain. Nutritional interventions intended to reduce brain serotonin synthesis during extended exercise enhance endurance performance, and there is strong evidence that increases and decreases in brain serotonin activity during prolonged exercise, respectively, accelerate and delay fatigue. There are several physiologically connected causes of fatigue. It is important to better understand how CNS effects affect fatigue in order to achieve maximum muscle performance in both daily life and athletics.

Purpose: The activity of plasma liver enzymes is intensified under the influence of sports activities, which is affected by the duration, intensity, type and method of training. The purpose of this study was to investigate the effect of a special endurance training session on the activity of serum alkaline phosphatase and aspartate aminotransferase liver enzymes in inactive young men. Methods: In this semi-experimental study, 16 young inactive men were purposefully selected and examined in two groups (experimental and control). The experimental group performed Bruce's protocol after preliminary warm-up. Blood samples were collected before the test, immediately after the test, 24 hours and 48 hours after the test from both groups at the same time, and the amount of serum ALP (Alkaline Phosphatase) and AST (Aspartate Transaminase) enzymes were measured using an Auto analyzer. Statistical analysis of the data, independent T-test was used to compare the results of two groups and Bonferroni's post hoc test was used to determine the difference between different stages of sampling with a minimum significance level (P≥0.05). Results: The results of the independent T-test in the comparison between the groups showed that there is a significant difference between the two groups in the amount of ALP enzyme in the time intervals immediately after the activity (P≥0.020), but in the time intervals of 24 (P≥0.177) and 48 hours (P≥0.136), there is no significant difference between the two groups after the activity. The results of the independent T test did not show any significant changes in the amount of AST enzyme in any of the time intervals in the comparison between groups. Conclusion: Fatigue-inducing sports activity leads to an increase in the amount of enzymes, ALP, this increase can be a sign of damage to liver cells or heart muscle. Considering the role of recovery in liver damage, it seems that by considering enough rest time, it is possible to help improve the adaptation process while preventing the occurrence of muscle and liver damage