Discussion and conclusion
- The main findings of the present study were that Brazilian jiu-jitsu fights resulted in a significant increase in glucose, lactate and cortisol concentrations, indicating a substantial activation of the glycolytic pathway. There was a significant reduction of isometric handgrip strength in the dominant hand with a tendency to reduction in the other hand.
- Thus, a great part of lactate formed probably originated from the glucose released through the degradation of muscular glycogen.
- The reliance on carbohydrate degradation and the lactate accumulation are related to the high-intensity intermittent actions conducted during the match.
- The increase in glucose concentration was probably influenced by the increase in cortisol concentration, which is a hormone that prevents hypoglycemia.
- Hypoglycemia: condition of low sugar in the blood
- Hypo- for low
- glyc- for sugar or glucose
- emia for condition of the blood
- Increases in cortisol are commonly observed in response to physical and psychological stress (Brownlee, et al., 2005), aspects also present during Brazilian jiu-jitsu competitions, because athletes perform many high-intensity actions during a typical match (Andreato, et al., 2013) and the psychological stress is a consequence of anxiety (Filaire, Sagnol, Ferrand, Maso, & Lac, 2001) and the constant decision-making process necessary to choose proper responses to opponents’ actions during combat sports (Andrea- to, et al., 2013).
- Filaire et al. (2001) noted that cor- tisol concentrations identified before regional and inter-regional competitions were superior to those observed in judokas at rest.
- In that case, it can be suggested that prior increase expresses anticipation, which can be of benefit, since it could increase the availability of energy during fights.
- Thus, the stress experienced by athletes before competition is im- portant, because performance tends to be impaired when no stress is experienced before competition (Martens, et al., 1990).
- There was also an increase of the IgA concen- trations as a consequence of the fights. Additionally, a significant correlation between IgA and cortisol was also found, despite the suggestion that the increase of glucocorticoid concentrations can sup- press activity of the immune system (Fleshner, 2000).
- Although a suppression of IgA is expected during intense physical efforts, the increase of IgA concentrations has been related to psychological stress, as revealed in a study by Zeier, Brauchli and Joller-Jemelka (1996), where the authors observed an increase of IgA concentrations along with an increase in cortisol amongst flight controllers after work shifts, because their work involved a considerably high level of tension and psychological stress.