Twelve weeks of soccer-specific training: effects on mucosal immunity, salivary alpha-amylase and body composition in male African youths

Purpose: The primary aim of this study was to determine the levels of salivary secretory IgA (sIgA) and salivary alpha-amylase (sAA) in young, black male soccer players, before and after 12 weeks of soccer-specific training. Methods: Thirty-four children (11–13 years) who were part of a youth soccer development training academy, participated in the study. The participants underwent 12 weeks of soccer-specific training. Resting saliva samples were collected 48 h before the commencement, and 48 h after the completion, of the training program. Samples were taken between 07:30 and 08:30, 90 min after waking. Body fat percentage (BF %), lean body mass (LBM) and cardiorespiratory fitness (CRF) were also measured. Results: Significant differences were found between pre- and post-training for body mass index (BMI) (P < 0.05), waist-to-hip ratio (P < 0.05), height (P < 0.0001), BF % (P < 0.0001) and LBM (P < 0.0001). sIgA secretion rate increased significantly from pre- to post-training (P < 0.05) however, no significant differences were found in sAA concentration (P > 0.05), sAA secretion rate (P > 0.05) or sIgA concentration (P > 0.05). The magnitude of differences from pre- to post-training applying Cohen’s d effect sizes (ES) were moderate (>0.5) for estimated VO _2max , sAA, sAA secretion rate, sIgA and sIgA secretion rate. Conclusion: These findings suggest that, 12 weeks of soccer-specific training enhances mucosal immunity and body composition and may have an effect on the sympathetic nervous system in black, male youths.