UNLABELLED: Tapering can be an effective way of enhancing performance after a period of intensive training, but the mechanisms for this ergogenic effect are unclear. It was hypothesized that overload training will increase oxidative stress through an accumulative effect of repeated high-intensity exercise, whereas tapering will improve the antioxidant defense system and alleviate oxidative stress. PURPOSE: To study the oxidative stress response to overload training and tapering. METHODS:A group of eight well-trained male endurance athletes (30+/-6 yr; 73+/-13 kg; 64+/-6 mL.kg.min) performed two 4-wk periods of training in a crossover design. Each period included a 2-wk build-up phase followed either by 2 wk of training at the same load (control) or by a week with a 40% increase in training load (overload) preceding a week with a 60% reduction in training load (taper). Performance was monitored through weekly 15-min cycling time trials preceded by a 45-min preload at 70% Wmax. Blood samples were taken before and after the time trials and analyzed for oxidatively modified heme (OxHm), methemoglobin (metHb), and glutathione redox status. RESULTS: Cycling time trials induced significant postexercise increases in levels of OxHm (+3.8%; P<0.001) and oxidized glutathione (GSSG: +13.9%; P<0.05) and decreases in metHb (-12.1%; P<0.001), reduced glutathione (GSH: -14.4%; P<0.001), and GSH/GSSG (-29.7%; P<0.001). Tapering was shown to significantly increase performance (+4.9%; P<0.05). Training modifications did not influence resting levels or exercise-induced changes of markers of oxidative stress. CONCLUSION: A short period of tapered training improves performance but does not seem to be associated with substantial changes in exercise-induced oxidative stress.
RCT Entities:
UNLABELLED: Tapering can be an effective way of enhancing performance after a period of intensive training, but the mechanisms for this ergogenic effect are unclear. It was hypothesized that overload training will increase oxidative stress through an accumulative effect of repeated high-intensity exercise, whereas tapering will improve the antioxidant defense system and alleviate oxidative stress. PURPOSE: To study the oxidative stress response to overload training and tapering. METHODS: A group of eight well-trained male endurance athletes (30+/-6 yr; 73+/-13 kg; 64+/-6 mL.kg.min) performed two 4-wk periods of training in a crossover design. Each period included a 2-wk build-up phase followed either by 2 wk of training at the same load (control) or by a week with a 40% increase in training load (overload) preceding a week with a 60% reduction in training load (taper). Performance was monitored through weekly 15-min cycling time trials preceded by a 45-min preload at 70% Wmax. Blood samples were taken before and after the time trials and analyzed for oxidatively modified heme (OxHm), methemoglobin (metHb), and glutathione redox status. RESULTS: Cycling time trials induced significant postexercise increases in levels of OxHm (+3.8%; P<0.001) and oxidized glutathione (GSSG: +13.9%; P<0.05) and decreases in metHb (-12.1%; P<0.001), reduced glutathione (GSH: -14.4%; P<0.001), and GSH/GSSG (-29.7%; P<0.001). Tapering was shown to significantly increase performance (+4.9%; P<0.05). Training modifications did not influence resting levels or exercise-induced changes of markers of oxidative stress. CONCLUSION: A short period of tapered training improves performance but does not seem to be associated with substantial changes in exercise-induced oxidative stress.
Authors: J Matthew Hinkley; Adam R Konopka; Miranda K Suer; Matthew P Harber Journal: Am J Physiol Regul Integr Comp Physiol Date: 2016-12-30 Impact factor: 3.619