To the best of our knowledge, this is the first study that analyzed monthly hormonal responses in relation to playing position and PT in elite basketball players along 4 consecutive seasons. The 3 main findings of this study suggest the following summaries. The first conclusion is that a players' hormonal status is playing position specific, with SFs and PFs presenting the most catabolic state. Second, players who played more than 25 minutes or less than 13 minutes need specific training interventions to improve recovery or to compensate for the lack of exercise stimulus, respectively. Finally, the last third of the regular season showed the most catabolic and/or stressed state with all players.
Hormonal responses according to playing position reveal significant differences of SFs and PFs compared with all other positions (point guards, shooting guards, and centers). Both positions shared lower TT and higher cortisol values (increased catabolic or stressed profile), especially compared with centers, who had the most anabolic profile (Figures 2 and 5). Our results extend previous findings on hormone-specific adaptations by types of sport and playing positions (5,13). This information can be used to develop position-specific training adjustments, taking into account not only between general player sizes but also among all traditional 5 playing positions. Our findings suggest that if TT/C is considered as a valid marker to determine metabolic status, the lowest values showed by SFs and PFs could indicate a high physical demand placed on these players. According to this hypothesis, PFs are the playing position that has changed the most recently, to become more fast and athletic than before. Conversely, the high TT/C values found in centers could reflect the emphasis on strength development for this playing position and where muscle hypertrophy is a training consequence.
In this study, analyses were undertaken according to PT, which is more precise than previous investigations that only differentiated between “starters” and “non-starters.” When divided into 5-minute intervals, with a total of 6 ranges, our results showed that players who played less than 5 minutes had the lowest TT and TT/C values and the highest ones of cortisol. In contrast, players who played between 11–15 minutes and 16–20 minutes showed the highest TT and TT/C values. When PT was grouped into 12-minute intervals, with a total of 3 ranges, results were similar. Players who played between 13 and 25 minutes showed the highest values of TT and TT/C, significantly higher than those who played less than 13 minutes (Figure 3). Although we are not aware of any comparable data in basketball literature, a possible explanation for these results could be that since TT increases in response to intense exercise sessions (23), players who played less than 13 minutes would not experience enough stimuli during official games, considered as the most intense sessions. For these players, the high cortisol concentrations could be explained by the emotional stress induced by their smaller perceived personal contribution to the team achievements (13,30). Conversely, players who played more than 25 minutes showed the largest decreases in TT concentration and in TT/C, which may reflect the cumulated fatigue (22). The results of this study suggest that players who play less than 13 minutes in official games should compensate for this lack of stimuli to adjust their hormonal profile to those who play between 13 and 25 minutes. In contrast, players with over 25 minutes of PT should require specific interventions to recover from the game overload.
Focusing on possible differences in hormonal values per month, our results showed significant differences between September, October, and March-April, coinciding with specific periods of the season: (a) the preseason, September and October, (b) the first two-thirds of regular season, November to February, and (c) the last third March and April (Figures 4–6). We would like to highlight mainly the preseason responses and the players' state at the end of the regular season. The preseason effects, typically characterized by high TL (25), are reflected in the September and October results. In September, cortisol showed significantly lower values than January-February and March-April. The increase in cortisol concentrations from September is possibly related to the physiological stress associated with the physical nature of the competitive basketball season and the psychological stress associated with official competition, which nonexistent in the preseason (17). These results agree with previous studies conducted in cyclists and football players (17), despite differences in the demand for these sports. In September, we also obtained significantly higher TT/C values compared with that of in March-April. The increase, as a metabolic status marker (3,20,31), could reflect the anabolic processes predominance in the organism (20,31,34), probably induced because of the maximal strength and high-intensity endurance training prioritized in this phase (25), as well as the appropriate player recovery process.
In the last third of the regular season (March-April), the players showed an increased catabolic and/or stressed profile hormonally. During the last phase of the season, the higher cortisol values were significantly different from the beginning of the season (September-October). The increment in cortisol values after a training and competition period has been reported by several authors (33). In Basketball, previous studies attribute this increased cortisol to the accumulated training and to the competition effect (15,16). However, there are studies that do not report a clear pattern of cortisol, such as Martínez et al. (21), who obtained an irregular pattern of cortisol throughout the season. The conflicting results and discrepancies of study conducted by Martínez et al. (21) could be explained by differences in periodization. Martínez’s participants played an international competition during the week and the play-offs in June, experienced a tapering phase (27), thus explaining the differences in cortisol. The subjects of this study, however, ended their season in mid-May and usually played 1 game per week only, a probable influence in the cortisol pattern. Another explanation for the lack of similar results with the aforementioned study can be related to the study design, as they performed the first blood sample in October, when the season had already begun. Furthermore, if we consider that cortisol has immunosuppressive effects in response to exercise (15), the large increase observed at the end of the season could lead increase risk to an athlete's injury or illness. Regarding TT/C, the behavior is the opposite of cortisol, obtaining the lowest values of the season in this phase. Our results do not match the pattern with those reported by Hoffman et al. (16) and Martinez et al. (21). Hoffman et al. (16) speculated that their seasonal hormonal pattern could be due to altered endocrine response by an incomplete recovery state by subjects. The discrepancies with the results of Martínez et al. with our results could be explained by the research design or teams' periodization differences. Our results and hypothesis would be supported by those presented by Argus et al. (2), who postulated that their results, obtained along rugby competition, may reflect the accumulated fatigue throughout the season or indicate lack of recovery (2,3), whose effects could lead to an alteration of the hypothalamic-pituitary-adrenal axis (34).
Finally, as future research continues to investigate endocrine changes in basketball, the studied biomarkers should be analyzed and compared with the external load from practices and games (e.g., accelerometers, GPS, or time motion). Additional relationships such as the psychological state (e.g., POMS, RESTQ-Sport, STAI), nutritional parameters and sleep quality, can provide a deeper understanding of seasonal fatigue.
A good understanding of the internal effects of a competitive season on each player may provide opportunity for enhanced programming strategies individually. Monitoring hormonal state (through plasma TT and cortisol) is recommended to prevent excessive stress caused by professional basketball season requirements. Hormonal status is professional basketball playing position-dependent, being SFs and PFs who present the most catabolic/stressed hormonal profile. Basketball players who play more than 25 minutes or less than 13 minutes need specific-training interventions to improve the recovery processes or to compensate the lack of stimuli, respectively. These individual interventions will be crucial at the last third of the season.
The authors of this article would like to thank Dr. Ramón Serra, team's Chief of Medical Services and Mútua Intercomarcal and Laboratorios Nogueras for their cooperation and timeliness in collecting samples. We would also like to thank Bàsquet Manresa organization, technical staff and players for their collaboration and Dr. Anne Delextrat and Mr. Carl Valle for help with preparation of this article.
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