Diurnal patterns of salivary alpha-amylase and cortisol secretion in female adolescent tennis players after 16 weeks of training

We examined the effects of 16 weeks of training on diurnal pattern of salivary alpha-amylase (sAA), cortisol, and the ratio of sAA over cortisol (AOC) in 12 national adolescent female tennis players. Stress and recovery were also evaluated using the Recovery-Stress-Questionnaire for Athletes-RESTQ-Sport. Data were collected after a 2-week rest (January, W-0), and 4 months after W-0 (W-16). Subjects collected five saliva samples throughout a day. While all participants displayed the previously shown decrease after awakening in adolescents at W-0, they showed a rise in the alpha-amylase awakening response and a higher alpha-amylase activity output (p < 0.01) at W-16 compared to W-0. For the daily rhythm of cortisol we found subjects having a low overall output of salivary cortisol (p < 0.01) and a blunted response to awakening at W-16. Furthermore, an increase in the ratio AOC at W-16, and a negative correlation between this ratio and Sport-specific recovery score. Our findings offer support for the hypothesis that increase of training load during the study period induced asymmetry activation between the two stress systems, in relation to psychological alterations and performance decrease. These results provide encouragement to continue exploring the impact of training program using a psychobiological approach among young athletes in order to prevent fatigue and preserve the health of these athletes. (C) 2012 Elsevier Ltd. All rights reserved.