Investigation of the Relationship Between Salivary Cortisol, Training Load and Subjective Markers of Recovery in Elite Rugby Union Players

Insufficient recovery can lead to a decrease in performance and increase the risk of injury and illness. The aim of this study was to evaluate salivary cortisol as a marker of recovery in elite Rugby Union players. Over a 10-week pre-season training period, 19 male elite Rugby Union players provided saliva swabs bi-weekly (Monday and Friday morning). Subjective markers of recovery were collected every morning of each training day. Session Rating of Perceived Exertion (sRPE) was taken after every training session and training load was calculated (sRPE x session duration). Multi-level analysis found no significant association between salivary cortisol and training load or subjective markers of recovery (all, p>0.05), over the training period. Compared to baseline (week 1), Monday salivary cortisol significantly increased in weeks 4 (14.94 ± 7.73 ng.ml; p=0.04), 8 (16.39 ± 9.53 ng.ml; p=0.01) and 9 (15.41 ± 9.82 ng.ml; p=0.02) and Friday salivary cortisol significantly increased in weeks 5 (14.81 ± 8.74 ng.ml; p=0.04) and 10 (15.36 ± 11. 30 ng.ml; p=0.03). The significant increase in salivary cortisol on certain Mondays may indicate players did not physically recover from the previous week of training or match at the weekend. The increased Friday cortisol levels and subjective marker of perceived fatigue indicated increased physiological stress from the weeks training. Regular monitoring of salivary cortisol combined with appropriate planning of training load, may allow sufficient recovery, to optimise training performance.