SummaryThe central aim of this review is to address the highly multidisciplinary topic of redox biology as related to exercise using an integrative and comparative approach rather than focusing on blood, skeletal muscle or humans. An attempt is also made to redefine ʻoxidative stressʼ as well as to introduce the term ʻalterations in redox homeostasisʼ to describe changes in redox homeostasis indicating oxidative stress, reductive stress or both. The literature analysis shows that the effects of non-muscledamaging exercise and muscle-damaging exercise on redox homeostasis are completely different. Non-muscle-damaging exercise induces alterations in redox homeostasis that last a few hours post exercise, whereas muscle-damaging exercise causes alterations in redox homeostasis that may persist for and/or appear several days post exercise. Both exhaustive maximal exercise lasting only 30s and isometric exercise lasting 1-3min (the latter activating in addition a small muscle mass) induce systemic oxidative stress. With the necessary modifications, exercise is capable of inducing redox homeostasis alterations in all fluids, cells, tissues and organs studied so far, irrespective of strains and species. More importantly, ʻexercise-induced oxidative stressʼ is not an ʻoddityʼ associated with a particular type of exercise, tissue or species. Rather, oxidative stress constitutes a ubiquitous fundamental biological response to the alteration of redox homeostasis imposed by exercise. The hormesis concept could provide an interpretative framework to reconcile differences that emerge among studies in the field of exercise redox biology. Integrative and comparative approaches can help determine the interactions of key redox responses at multiple levels of biological organization.Key words: antioxidant, biomarker, eccentric, free radical, training. THE JOURNAL OF EXPERIMENTAL BIOLOGY 1616The ʻgoodʼ (antioxidants), the ʻbadʼ (reactive species) and the ʻuglyʼ (oxidative stress) 1 The distinction drawn in the section heading is schematically used to parody the popular manichaeistic view that antioxidants are considered 'useful' entities, reactive species are considered 'harmful' entities and oxidative stress is considered a 'negative' state. Certainly, the reality is much more complicated and antioxidants, reactive species and oxidative stress can serve both useful and detrimental roles, which are dependent on the biological context (within an organism), which in turn are greatly dependent on the environmental context (outside an organism). AntioxidantsAdmittedly, to define the term 'antioxidant' is a difficult task. In this paper, antioxidant is defined as any mechanism, structure and/or substance that delays, prevents or removes oxidative modifications to a target molecule (Halliwell and Gutteridge, 2007;Pamplona and Costantini, 2011). Antioxidants can be complex molecules such as the superoxide dismutases and peroxiredoxins, or simpler ones such as uric acid and glutathione (Gutteridge and Halliwell, 2010). They can be broa...

The aim of this study was to determine the effects of a simulated one-day Greco-Roman wrestling tournament on selected performance and inflammatory status indices. Twelve competitive wrestlers (22.1 ± 1.3 years) completed five matches according to the official Olympic wrestling tournament regulations following a ~6% weight loss. Performance measurements, muscle damage assessment, and blood sampling were performed before and following each match. Performance and inflammatory markers were not affected by weight loss. Mean wrestling heart rate reached ~85% of maximal and lactate concentration exceeded 17 mM. Fatigue rating demonstrated a progressive rise (P < 0.05) throughout the tournament, peaking in match 4. Performance demonstrated a progressive deterioration (P < 0.05) throughout the tournament, especially in the last two matches (P < 0.05), with upper-body measures exhibiting a greater decline (P < 0.05) and remaining below baseline (P < 0.05) until the end of the tournament. Muscle damage markers increased during the course of the tournament with upper limbs affected more. Creatine kinase activity, CRP levels, IL-6 concentration, and leukocyte counts increased (P < 0.05) progressively throughout the tournament, peaking in the last two matches. Cortisol, epinephrine and norepinephrine increased (P < 0.05) after each match, but testosterone declined (P < 0.05) progressively, reaching a nadir before the last match. This inflammatory response was accompanied by a marked increase (p < 0.05) in lipid peroxidation, protein oxidation, and antioxidant status markers indicating the development of oxidative stress. These results suggest that a one-day wrestling tournament may induce significant physiological demands on wrestlers that may adversely affect their performance and inflammatory status especially during the later stages of the tournament.

It is reported for the first time that only 30 min of eccentric exercise per week for 8 wk was sufficient to improve health risk factors.