Somatotype and stress hormone levels in young soccer players

The relationship between somatotype and cortisol and adrenocorticotropic (ACTH) hormone concentrations at rest or after exercise in adolescent soccer players at different time points throughout a soccer season is not understood. Therefore, the aim of this study was to examine the relationship between somatotype and cortisol and ACTH concentrations at rest and after exercise in adolescent soccer players at different time points during a soccer season.

During the first 4 months of the soccer season, 47 soccer players (between 15-17 years of age) were tested at three different time points including at baseline, after 6 weeks, and at the end of 4 months. Testing included anaerobic threshold (AnT, km/h) and maximal speed of running (Max, km/h) were measured with Conconi protocol on treadmill. Before and after a maximal exercise Test, plasma levels of cortisol (ug/dL) and ACTH (pg/ml) were assessed by chemiluminometry enzyme amplificated method. Heath-Carter anthropometric somatotype model was used to determine 13 elements of somatotype. Descriptive statistics and multiple regression were used for statistical analysis (P<0.05).

Body composition and AnT were not significantly different between each time point of testing. The mesomorph-ectomorph (N.=21), balanced mesomorph (N.=8) and balanced ectomorph (N.=7) were the most frequent somatotypes. There were significant decrements of cortisol plasma levels (at rest 33.4%; after test 27.46%), with insignificant changes of ACTH plasma levels, after 6 weeks of preparation phase and after finishing of half season, at rest and after maximal treadmill test. There were significant correlation between ACTH levels at rest (R=0.44; P<0.01) and some somatotypes (mesomorph endomorph, central and balanced endomorph) and ACTH levels after maximal exercise test (R=0.36; P<0.05) and balanced ectomorph and endomorph mesomorph. There were significant correlation between cortisol levels after maximal exercise test at the beginning of training process (R=0.59; P<0.01) and some somatotypes (mesomorph ectomorph, mesomorph endomorph, balanced endomorph and endomorph mesomorph) and after the finishing of training process (R=0.62; P<0.01) and some somatotypes (central, balanced ectomorph and mesomorph ectomorph).

The significant decreases of cortisol plasma levels during soccer training process could indicate a stagnation of training process, accordingly with insignificant changes of AnT. The significant correlations of some somatotypes with stress hormonal responses could only suggest that the somatotype characteristics of young soccer players could be of interest in process of selection and planning of soccer training process with an essential need for more studies.