Zusammenfassung

Objective: Nitric oxide (NO) is a gas with vasodilator, antioxidant and metabolic regulatory effects. However, NO may be converted into an oxidant substance, under oxidative stress conditions as severe exercise, reducing the bioavailability of NO. Therefore, NO may take part in training adaptations. The main aim of this study was to investigate the effects of a volleyball match on serum NO level and oxidant/antioxidant status, as well as some physiological stress responses. Materials and Methods: Healthy female competitive volleyball players (n=12), and a control group (n=12) that gave up regular volleyball training at least three years prior to to the study, aged 16-22 years old, carried out spike-block jump and agility T-tests, and lactate elimination speed was determined following a Yoyo intermittent recovery test. Heart rate (HR), fingertip blood lactate levels, rate of perceived exertion (RPE) were measured during volleyball matches. Serum NO level was determined spectrophotometrically with the "Griess Reaction" method. Serum total oxidant status and total antioxidant status (TAS), erythrocyte glutathione peroxidase activity, and physiological stress markers such as serum creatine kinase (CK), lactate dehydrogenase (LDH), alanine- (ALT) and aspartate amino transferase (AST) activities by enzymatic-colorimetric methods, using venous blood samples taken before and following the matches. Results: The players’ HR, lactate and RPE levels during a match were significantly lower than those of the controls. Post-match serum TAS, CK, LDH and AST levels were significantly higher than baseline values for both player (p≤0.05) and control (p≤0.01) groups. However, post-match serum NO levels were higher than pre-match levels only in the player group (p≤0.05). Conclusion: Increased NO and lowered physiological stress levels following a match may result from a higher vasodilator and recovery capacity based on training adaptation in the players, as well as the low intensity of the matches. The observation that serum NO ...