Η Επίδραση Της Έκκεντρης Προπόνησης Σε Δείκτες Μυϊκής Βλάβης Και Οξειδωτικού Στρες

Abstract

Anastasios A. Theodorou : The effect of eccentric training on muscle damage and redox status indices (Under the supervision of Athanasios Jamurtas, Assistand Professor)Antioxidant supplementation is quite often among athletes in an attempt to counteract the increased production of free radicals during exercise and especially after exerciseinduced muscle damage (eccentric). Recently an increasing number of studies reported negative effects of antioxidant supplementation on the training and cellular adaptations to chronic exercise. The aim of the present study was to investigate the effects of vitamin C and E supplementation on muscle performance, blood and muscle redox status, hemolysis and blood lipid profile in both trained and untrained individuals after acute and chronic exercise. After previous investigations of our group, a specific type of exercise was applied (eccentric) in order to produce long lasting and extensive changes in all biomarkers and examine more easily any effects of antioxidant supplementation. In a double-blinded fashion, participants received either a daily oral supplementation of vitamin C and vitamin E (n=14) or placebo (n=14) for eleven weeks. Following baseline tests, volunteers performed an eccentric exercise session two times per week for four weeks. Before and after the chronic eccentric exercise volunteers were subjected to one session of acute eccentric exercise, and physiological measurements were performed as well as blood samples and muscle biopsies (from 8 participants) were collected. The present results failed to support any effect of antioxidant supplementation; eccentric exercise similarly modified muscle damage and performance, blood redox status, hemolysis and lipid profile in both supplemented and non-supplemented groups. This is despite the fact that eccentric exercise induced marked changes in muscle damage and performance as well as redox status and lipid profile for several days after exercise. The complete lack of any effect on the physiological and biochemical outcome measures employed questions the validity of using orally antioxidant supplementation as redox modulators of muscle and redox status in healthy humans. Moreover, the lack of any effect of antioxidant supplementation on training and cellural adaptation to exercise observed in this study, opposed previous studies suggesting that antioxidant may block training adaptations.