The present study investigated whether short-term oral administration of glucocorticoid would modify performance and selected hormonal and metabolic parameters during submaximal exercise in healthy women. Nine recreational female athletes completed cycling trials at 70-75% VO(2) max until exhaustion after either placebo (Pla, gelatin) or oral prednisone (Cor, Cortancyl, 50 mg per day for 1 week) treatment, according to a double-blind and randomized protocol. Blood samples were collected at rest; after 10, 20, and 30 min of exercise; at exhaustion; and after 10 and 20 min of passive recovery for adrenocorticotrophic hormone (ACTH), dehydroepiandrosterone (DHEA), prolactin (PRL), growth hormone (GH), insulin (Ins), blood glucose (Glu), and lactate (Lac) determination. Cycling time was significantly increased with short-term Cor intake (Cor: 66.4 +/- 8.4 vs. Pla: 47.9 +/- 6.7 min, P < 0.01). ACTH and DHEA remained completely blunted throughout the experiment with Cor versus Pla (P < 0.01), whereas GH and PRL were significantly decreased with Cor after, respectively, 20 and 30 min of exercise (P < 0.05). No significant difference in Ins or Glu values was found between the two treatments but Lac concentrations were significantly increased with Cor versus Pla between 10 and 30 min of exercise (P < 0.05). These data indicate that short-term glucocorticoid intake improved endurance performance in women, but further investigation is needed to determine whether these results are applicable to elite female athletes and, if so, current WADA legislation needs to be changed.

This study examined the effect of pedal cadence on the heterogeneity of muscle deoxygenation during exercise of moderate intensity. Twelve healthy subjects performed 6 min of cycling at 40 and 100 r · min(-1) at 80% of the workload corresponding to the gas exchange threshold. Gas exchanges were measured breath by breath during each exercise. Muscle deoxygenation (HHb, i.e., O2 extraction) was monitored continuously by near-infrared spectroscopy at eight sites on the vastus lateralis. The heterogeneity of HHb was assessed using the relative dispersion of the signal measured at the eight sites (i.e., 100 × standard deviation/mean). HHb was not altered by the pedal cadence, whereas pulmonary V̇O2 was higher at 100 r · min(-1) than at 40 r · min(-1) (p < 0.001). The relative dispersion of HHb was significantly higher at 100 r · min(-1) than at 40 r · min(-1) (p < 0.001). These results indicate that pedal cadence has no effect on O2 extraction but that an elevated cadence would increase muscle V̇O2, suggesting an increase in muscle blood flow. Elevated cadence also induced greater heterogeneity of the muscle's V̇O2/Q̇O2 delivery ratio, suggesting a change in the adequacy between O2 demand and O2 delivery in some regions of active muscle.

These data are consistent with previous studies on blood samples and suggest that non-invasive saliva samples may offer a practical approach to assessing pituitary-adrenal function continuously during and after short-term corticosteroid therapy.

The purpose of this study was to examine salivary cortisol, dehydroepiandrosterone (DHEA), and testosterone responses to the bench press in an international powerlifting competition and to determine whether these salivary hormone concentrations could be used to predict performance. Twenty-six elite athletes (13 females and 13 males) provided saliva samples during the official weighing-in and after the last attempt at the bench press, as well as at baseline on a non-competition day. Performance index was determined with the Wilks formula, which adjusts powerlifting scores according to body mass. Salivary cortisol concentrations were significantly increased in all subjects after the bench press (p < 0.01), whereas DHEA concentrations were significantly increased in women (p < 0.01) but not in men after the bench press. No significant change in testosterone concentrations was observed during the experiment in either men or women, which resulted in a marked decrease in the testosterone/cortisol ratio. The performance index showed no significant correlation with any of the hormone responses to competition. In conclusion, despite the increase in stress adrenocortical hormone responses to an international powerlifting competition, these hormone concentrations alone are not predictors of bench press performance in elite powerlifting athletes.

No abstract