ABSTRACT
This chapter addresses the production of free radicals at rest as well as during and in response to exercise or training. It reflects upon the negative and positive effects free radicals can have on skeletal muscles, highlighting the signalling functions of free radicals in the process of physiological adaptation to training. For the time being, identifying the optimal balance remains elusive, making the area of free radicals, antioxidants and training, especially in athletes, a ripe one for further research. Particular interest in antioxidant supplements has arisen among athletes and people who train regularly. Indeed, antioxidants are among the most common sport supplements used by amateur and professional athletes. In any case, it is clear considering the positive and negative effects of free radicals, and that the right balance between these and antioxidants is necessary for health and optimal training effectiveness.
