Although regular muscular exercise is known to have many beneficial effects, exercise results in an increased production of radicals and other forms of reactive oxygen species (ROS).<sup>4 Borzone G., Zhao B., Merola A.J. , e al. Detection of free radicals by electron spin resonance in rat diaphragm after resistive loading J Appl Physiol 1994 ;  77 : 812

Cliccare qui per andare alla sezione Riferimenti, 8 Davies K., Quintanilha A., Brooks G. , e al. Free radicals and tissue damage produced by exercise Biochem Biophys Res Commun 1982 ;  107 : 1198  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 11 Halliwell B., Gutteridge J.M. Iron toxicity and oxygen radicals Free Radicals in Biology and Medicine New York: Oxford Univ. Press (1989).  1-276

Cliccare qui per andare alla sezione Riferimenti, 29 O'Neill C.A., Stebbins C.L., Bonigut S. , e al. Production of hydroxyl radicals in contracting skeletal muscle of cats J Appl Physiol 1996 ;  81 : 1197

Cliccare qui per andare alla sezione Riferimenti, 36 Reid M., Haack K., Franchek K. , e al. Reactive oxygen in skeletal muscle: I. Intracellular oxidant kinetics and fatigue in vitro J Appl Physiol 1992 ;  73 : 1797

Cliccare qui per andare alla sezione Riferimenti</sup> In fact, evidence exists to implicate ROS as an underlying cause in exercise-induced disturbances in muscle homeostasis (e.g., redox status), which could result in muscle fatigue or injury.<sup>16 Ji L.L., Stratman F., Lardy H. Antioxidant enzyme systems in rat liver and skeletal muscle Arch Biochem Biophys 1988 ;  263 : 150

Cliccare qui per andare alla sezione Riferimenti, 26 Nashawati E., Dimarco A., Supinski G. Effects produced by infusion of a free radical-generating solution into the diaphragm Am Rev Respir Dis 1993 ;  147 : 60  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 29 O'Neill C.A., Stebbins C.L., Bonigut S. , e al. Production of hydroxyl radicals in contracting skeletal muscle of cats J Appl Physiol 1996 ;  81 : 1197

Cliccare qui per andare alla sezione Riferimenti, 37 Reid M., Shoji T., Moody M. , e al. Reactive oxygen in skeletal muscle: II. Extracellular release of free radicals J Appl Physiol 1992 ;  73 : 1805

Cliccare qui per andare alla sezione Riferimenti, 41 Shindoh A., Dimarco A., Thomas A. , e al. Effect of N-acetylcysteine on diaphragm fatigue J Appl Physiol 1990 ;  68 : 2107

Cliccare qui per andare alla sezione Riferimenti</sup> Given the potential role of ROS in contributing to muscle fatigue or injury, it is not surprising that skeletal muscle myocytes contain defense mechanisms to reduce the risk for oxidative damage. Two major classes of endogenous protective mechanisms (i.e., enzymatic and nonenzymatic antioxidants) work as a unit to reduce the harmful effects of ROS in cells. This article provides a brief overview of cellular antioxidants and summarizes the current understanding of the effects of nutritional antioxidants on exercise performance. This article begins with a discussion of the primary units that comprise the endogenous antioxidant defense system in cells.