Can salivary testosterone and cortisol reactivity to a mid-week stress test discriminate a match outcome during international rugby union competition?

ObjectivesEvidence suggests that stress-induced changes in testosterone and cortisol are related to future competitive behaviours and team-sport outcomes. Therefore, we examined whether salivary testosterone and cortisol reactivity to a mid-week stress test can discriminate a match outcome in international rugby union competition.DesignSingle group, quasi-experimental design with repeated measures.MethodThirty-three male rugby players completed a standardised stress test three or four days before seven international matches. Stress testing involved seven minutes of shuttle runs (2 × 20 m), dispersed across one-minute stages with increasing speeds. Salivary testosterone and cortisol were measured in the morning, along with delta changes from morning to pre-test (Morn-PreΔ) and pre-test to post-test (Pre-PostΔ). Data were compared across wins (n = 3) and losses (n = 4).ResultsThe Morn-PreΔ in cortisol increased before winning and decreased prior to losing (p < 0.001), with a large effect size difference (d = 1.6, 90% CI 1.3-1.9). Testosterone decreased significantly across the same period, irrespective of the match outcome. The Morn-PreΔ in testosterone and cortisol, plus the Pre-PostΔ in testosterone, all predicted a match outcome (p ≤ 0.01). The final model showed good diagnostic accuracy (72%) with cortisol as the main contributor.ConclusionsThe salivary testosterone and cortisol responses to mid-week testing showed an ability to discriminate a rugby match outcome over a limited number of games. The Morn-PreΔ in cortisol was the strongest diagnostic biomarker. This model may provide a unique format to assess team readiness or recovery between competitions, especially with the emergence of rapid hormonal testing

Is salivary cortisol moderating the relationship between salivary testosterone and hand-grip strength in healthy men?

This study examined the moderating effect of cortisol (C) on the relationship between testosterone (T) and hand-grip strength (HGS) in healthy young men. Sixty-five males were monitored for salivary T, C and HGS before and 15 min after a short bout (5 × 6-s trials) of sprint cycling exercise. Sprint exercise promoted (p < .05) positive changes in T (6.1 ± 24.9%) and HGS (3.4 ± 7.5%), but a negative C response (−14.4 ± 33.1%). The T and C measures did not independently predict HGS, but a significant T × C interaction was found in relation to these outcomes. Further testing revealed that pre-test T and HGS were negatively associated (p < .05), but only in men with high C levels. The exercise changes in T and HGS were also negatively related in men with low C levels (p < .05), but no relationship was seen in men with high C levels. In summary, complex relationships between T and HGS emerged when considering C as a moderating variable. The pre-test combination of high C and low T levels favoured absolute HGS, whereas low pre-test C levels and a smaller T change were linked to larger HGS changes. These associations suggest that, in the current format, T is not necessarily anabolic to muscle strength in healthy young men. Such complexities could also explain some of the inconsistent T relationships with physical performance in lesser trained male populations

Skill execution and sleep deprivation: effects of acute caffeine or creatine supplementation - a randomized placebo-controlled trial

<p>Abstract</p> <p>Background</p> <p>We investigated the effects of sleep deprivation with or without acute supplementation of caffeine or creatine on the execution of a repeated rugby passing skill.</p> <p>Method</p> <p>Ten elite rugby players completed 10 trials on a simple rugby passing skill test (20 repeats per trial), following a period of familiarisation. The players had between 7-9 h sleep on 5 of these trials and between 3-5 h sleep (deprivation) on the other 5. At a time of 1.5 h before each trial, they undertook administration of either: placebo tablets, 50 or 100 mg/kg creatine, 1 or 5 mg/kg caffeine. Saliva was collected before each trial and assayed for salivary free cortisol and testosterone.</p> <p>Results</p> <p>Sleep deprivation with placebo application resulted in a significant fall in skill performance accuracy on both the dominant and non-dominant passing sides (p < 0.001). No fall in skill performance was seen with caffeine doses of 1 or 5 mg/kg, and the two doses were not significantly different in effect. Similarly, no deficit was seen with creatine administration at 50 or 100 mg/kg and the performance effects were not significantly different. Salivary testosterone was not affected by sleep deprivation, but trended higher with the 100 mg/kg creatine dose, compared to the placebo treatment (p = 0.067). Salivary cortisol was elevated (p = 0.001) with the 5 mg/kg dose of caffeine (vs. placebo).</p> <p>Conclusion</p> <p>Acute sleep deprivation affects performance of a simple repeat skill in elite athletes and this was ameliorated by a single dose of either caffeine or creatine. Acute creatine use may help to alleviate decrements in skill performance in situations of sleep deprivation, such as transmeridian travel, and caffeine at low doses appears as efficacious as higher doses, at alleviating sleep deprivation deficits in athletes with a history of low caffeine use. Both options are without the side effects of higher dose caffeine use.</p

New evidence for the short-term effects of testosterone and cortisol upon athletic performance and training adaptation in elite male rugby players

For elite athletes, testosterone and cortisol play an important role in the training process by controlling long-term muscle growth and performance. Studies now support the existence of short-term hormonal effects upon athletic performance and training adaptation, especially for strength-trained athletes. Elite rugby players represent one group of strength athletes for which there is little hormonal information. The major aims of the work in this thesis were to measure, confirm and utilize the short-term effects of testosterone and cortisol to improve performance and adaptation in elite male rugby players. Experiment one validated the salivary testosterone (Sal-T) and cortisol (Sal-C) concentration (v. plasma) measures during dynamic changes induced by a 30-second cycle sprint, and confirmed the ability of sprint exercise to elevate the salivary hormones. Experiment two was undertaken to confirm hormonal relationships with running speed, squat jump (SJ) and bench throw (BT) power, and box squat (BS) and bench press (BP) one repetition maximum (1RM) strength in rugby players. The salivary hormone concentrations of players correlated to various speed, power and strength measures. This study also revealed performance similarities and differences between larger rugby forwards and smaller backs. Allometric scaling was found effective in normalizing power and strength in rugby forwards and backs in Experiment three. Experiments four and five evaluated the effects of sprint exercise (as a potentiating stimulus) upon the salivary hormones and workout performance and training adaptation in rugby players. A 40-second cycle sprint improved BS 1RM (2.6 ± 1.2%) and elevated Sal-T concentrations. A 40-second grinder sprint also improved BP 1RM (2.8 ± 1.0%) with the workout differences (%) in hormone concentrations correlating to BP performance. Thus, the salivary hormonal changes that occurred offered one possible mechanism to explain these improvements. These results were not replicated in a four-week training study. The training group performing a 40-second cycle sprint showed similar improvements in SJ power (peak 8.2 ± 2.9%, mean 11.8 ± 2.6%) and BS 1RM (20.5 ± 2.6%), compared to a control group (11.9 ± 3.6%, 18.6 ± 4.8%, 23.2 ± 1.3%, respectively). Still, for all players combined, resting salivary hormone concentrations were correlated to workout power and strength, thereby potentially moderating the training improvements. This work provides new evidence for the short-term effects of testosterone and cortisol upon athletic performance and training adaptation in elite male rugby players. This is novel information with important implications for examining, interpreting and utilizing hormones in sport science research and practice