Testosterone and cortisol are more predictive of choice behavior than a social nudge in adult males on a simple gift give-get task.

Reproducibility of social research is ambitious, and evidence supporting this argument is increasing in psychology and social science research. This may be attributed to, in part, the high volume of qualitative research methodology used in social research along with difficulties in the reliability of measurement techniques. Therefore, use of more and better objective measures to complement existing techniques in social research are necessitated. To highlight this point we explored the success of give-get nudge in adults. Nudge being a subtle intervention to influence choice, without restricting choice. We also wanted to explore whether testosterone and cortisol, as objective psychophysiological markers, could explain nudge outcome. Participants were asked what they would like to get for Christmas, or what they would like to give. They were then presented with two chocolates, one big and one small, and instructed to take as a "reward" for their participation with the knowledge there was one other participant to take chocolate after them. It was hypothesized that those asked to give something for Christmas would take the smaller reward and vice versa. Salivary testosterone and cortisol were measured prior to, and 10 min after completing the exercise. The nature of the nudge itself did not predict behavior, but the hormone measures did. We speculate that testosterone may focus an individual on the nature of the question (nudge), while cortisol encourages self-focus. These results support the need to combine existing social research techniques with more objective markers.

Menstrual variation in the acute testosterone and cortisol response to laboratory stressors correlate with baseline testosterone fluctuations at a within- and between-person level.

Studies have compared HPA and HPG stress reactivity across the follicular and luteal phases to assess the menstrual impact of estradiol and progesterone fluctuations. Ovulatory shifts in baseline and stressor-induced testosterone among athletic women offer a new framework to explore these responses. Here we investigated menstrual variation in baseline testosterone as a predictor of the acute testosterone and cortisol response to laboratory stressors in female athletes. Using a semi-randomized crossover design, thirty athletic women completed a physical (4 × 6-s bike sprints) and psychological (5 × 2-min cognitive tests with social evaluation) stressor on day seven (D7), 14 (D14), and 21 (D21) of a menstrual cycle. Baseline fluctuations and acute changes in salivary testosterone and cortisol were measured. The D14 testosterone response to both stressors (13.7%) exceeded D7 (7.3%) and D21 (7.0%), whereas cortisol was less responsive on D14 (9.8%) than D7 (13.0%) and D21 (12.0%); all moderate to large effect size differences (p < 0.01). Baseline testosterone, which presented large individual and menstrual variation with a D14 peak, was significantly related (moderate correlations) to testosterone and cortisol stress reactivity on a between-person level. Both outcomes were related (weak correlations) to within-person fluctuations in baseline testosterone, but these effects were mediated by testing day. In conclusion, menstrual variation in baseline testosterone concentration correlated with testosterone and cortisol reactivity to a physical and psychological stressor. Thus, gradients of stressor-induced hormonal change showed some dependency to endogenous testosterone, both individual differences and fluctuations over time, among naturally cycling athletic women.Lay summaryThe female menstrual cycle is accompanied by dramatic shifts in estradiol and progesterone concentration, but less is known about testosterone variability and its role in stress regulation. In this study, menstrual fluctuations in baseline testosterone concentration correlated with acute testosterone and cortisol reactivity to laboratory stressors.

A longitudinal investigation of bidirectional and time-dependent interrelationships between testosterone and training motivation in an elite rugby environment.

In sport, testosterone has been positioned as a substrate for motivation with both directional and time dependencies. However, evidence is scarce when considering the complexities of competitive sport and no work has explicitly modeled these dependencies. To address these gaps, we investigated the bidirectional and time-dependent interrelationships between testosterone and training motivation in an elite rugby environment. Thirty-six male athletes were monitored across training weeks before and after eight international rugby matches. Pre-breakfast measures of salivary testosterone and training motivation (1-10 rating) were taken on training, competition, and recovery days (up to 40 tests). Using a continuous-time (CT) model, within-person estimates of autoregressive effects (persistence) and cross-lagged effects (relationships) were derived. A stronger, more persistent temporal association was identified for testosterone than for motivation. Cross-lagged effects verified that training motivation was positively related to testosterone at latter time points (p < 0.001). Discrete-time analyses revealed a non-linear association; increasing in strength from a zero-time lag to peak after 2.83 days (standardized effect = 0.25), before dissipation over longer lagged intervals. The testosterone relationship with ensuing training motivation was also positive, but non-significant. Match effects also appeared (p < 0.001) with a predicted decline in training motivation, but a rise in testosterone, at match onset. In summary, a positive association emerged between within-person fluctuations in self-appraised motivation to train and testosterone concentration in an elite rugby environment. The lagged, non-linear nature of this relationship and match predictions on both outcomes support, and extend, theoretical models linking testosterone and competitive behaviors.

Physiological and Performance Effects of Caffeine Gum Consumed During a Simulated Half-Time by Professional Academy Rugby Union Players.

Russell, M, Reynolds, NA, Crewther, BT, Cook, CJ, and Kilduff, L. Physiological and performance effects of caffeine gum consumed during a simulated half-time by professional academy rugby union players. J Strength Cond Res 34(1): 145-151, 2020-Despite the prevalence of caffeine (CAF) as an ergogenic aid, few studies have examined the use of caffeinated gums, especially during half-time in team sports. The physiological (blood lactate and salivary hormone concentrations) and performance (repeated sprints and cognitive function) effects of consuming CAF gum during a simulated half-time were examined. Professional academy rugby union players (n = 14) completed this double-blind, randomized, counterbalanced study. After pre-exercise measurements, players chewed a placebo (PLC) gum for 5 minutes before a standardized warm-up and completing repeated sprint testing (RSSA1). Thereafter, during a 15-minute simulated half-time period, players chewed either CAF (400 mg; 4.1 ± 0.5 mg·kg) or PLC gum for 5 minutes before completing a second repeated sprint test (RSSA2). Blood lactate, salivary testosterone and cortisol concentrations, and indices of cognitive function (i.e., reaction time and Stroop test) were measured at baseline, pre-RSSA1, post-RSSA1, pre-RSSA2, and post-RSSA2. Sprint performance was not affected by CAF (p = 0.995) despite slower sprint times after the first sprint of both RSSA tests (all p < 0.002). After half-time, salivary testosterone increased by 70% (+97 ± 58 pg·ml) in CAF vs. PLC (p < 0.001), whereas salivary cortisol remained unchanged (p = 0.307). Cognitive performance was unaffected by time and trial (all p > 0.05). Although performance effects were absent, chewing CAF gum increased the salivary testosterone concentrations of professional rugby union players over a simulated half-time. Practitioners may, therefore, choose to recommend CAF gum between successive exercise bouts because of the increases in salivary testosterone observed; a variable associated with increased motivation and high-intensity exercise performance.

Within- and between-person variation in morning testosterone is associated with economic risk-related decisions in athletic women across the menstrual cycle.

Literature suggests that women experience ovulatory shifts in risk-taking behaviours across different domains, which might be partly attributed to changes in testosterone (T). Thus, we investigated associations between menstrual variability in T concentrations and economic risk-related decisions among athletic women. Thirty-five women were monitored across three consecutive menstrual cycles. Testing occurred on day seven (D7), 14 (D14) and 21 (D21) following the onset of menses. The morning (7 to 8 am) assessment of salivary T (sal-T) and cortisol (sal-C) was followed by the economic Hawk-Dove game (11 am to 12 pm) played in pairs, where hawk decisions were used to index risk. Morning sal-T concentration increased from D7 to D14, before decreasing on D21 (p < 0.001), representing moderate effect size (ES) changes of 0.6 to 0.8. Morning sal-C did not vary over time. Hawk choices paralleled the sal-T results, being elevated on D14 (p < 0.001) with large ES changes of 1.8. Regression analyses revealed that morning sal-T concentration was positively related (p ≤ 0.01) to the number of hawks chosen between- (beta = 0.47) and within-participants (beta = 0.10) when controlling for training hours and menstrual day. In summary, the risk-related choices of athletic women during a dyadic contest covaried with morning sal-T concentrations across the menstrual cycle. Both outcomes were positively correlated on a within- and between-person level. Confirming the major sources of T variation across the menstrual cycle, whilst discerning its relationship with other risk-related behaviours, would be worthwhile avenues for research.

Neuromuscular, physiological and perceptual responses to an elite netball tournament.

To examine responses to an International netball tournament, female athletes (n= 11) played three matches over consecutive days. External (accelerometry) and internal (heart rate; HR, session; sRPE, and differential; dRPE, rating of perceived exertion) load measures quantified match intensity. On match-day mornings, and three days after match 3, well-being (brief assessment of mood; BAM+), biochemical (creatine kinase concentration; CK), neuromuscular (jump height; JH, peak power output; PPO) and endocrine function (salivary cortisol; C, testosterone; T, concentrations) were assessed. External load was similar between matches whereas dRPE and sRPE were greatest for match 3. Following match 1, CK increased, whereas BAM+, JH, C and T decreased. Following two matches, BAM+, PPO, and T decreased with CK increasing versus baseline. Following consecutive matches, CK (likely moderate; 27.9% ± 19.5%) and C (possibly moderate; 43.3% ± 46.8%) increased, whilst BAM+ (possibly moderate; -20.6% ± 24.4%) decreased. Three days post-tournament BAM+, T, PPO, and JH decreased. Mid-court elicited higher mean HR (possibly moderate; 3.7% ± 3.8%), internal and external intensities (possibly very large; 85.7% ± 49.6%) compared with goal-based positions. Consecutive matches revealed a dose-response relationship for well-being and physiological function; a response evident three days post-tournament.

The salivary testosterone response to a chance-determined contest is associated with face-gazing behaviours in athletic women.

Human gaze is an important indicator of dominant and submissive behaviours related to positioning in a social hierarchy. This study investigated face gazing after a chance-determined contest and its linkage to salivary testosterone (sal-T) reactivity in athletic women. Twenty-six women athletes completed a coin-toss game on days 7 (D7), 14 (D14) and 21 (D21) of a single menstrual cycle. The game was played against an unknown opponent of similar age with the winner congratulated and rewarded with all coins. Gazing towards an opponent's head or face was timed after each contest (over 2 min) from video footage. Salivary T (sal-T) was assessed before and 15 min after these contests. The sal-T residuals increased after winning and decreased after losing on D7, D14 and D21 (p < 0.05). Gaze times were longer after a loss (M = 7.8 s) than a win (M = 3.1 s) across all days. Regression analyses revealed that the sal-T residuals and contest outcome interacted to predict gaze time. Upon deconstruction we found that, when losing a contest, a larger sal-T response (i.e., smaller decline) predicted a longer gaze (ß = 1.71, p = 0.004), but no association was evident when winning (ß = -0.06, p = 0.821), and these slope patterns differed (p = 0.011). In conclusion, winning a contest by chance increased sal-T responsivity and decreased opponent gaze across the menstrual cycle. A positive relationship between individual sal-T reactivity and gaze duration was observed, but only when losing. These preliminary results support suggestions that women's T may help modulate post-competition behaviours (e.g., face gazing) possibly to achieve social cohesion and cooperation.

The Effects of a Single Whole-Body Cryotherapy Exposure on Physiological, Performance, and Perceptual Responses of Professional Academy Soccer Players After Repeated Sprint Exercise.

Russell, M, Birch, J, Love, T, Cook, CJ, Bracken, RM, Taylor, T, Swift, E, Cockburn, E, Finn, C, Cunningham, D, Wilson, L, and Kilduff, LP. The effects of a single whole-body cryotherapy exposure on physiological, performance, and perceptual responses of professional academy soccer players after repeated sprint exercise. J Strength Cond Res 31(2): 415-421, 2017-In professional youth soccer players, the physiological, performance, and perceptual effects of a single whole-body cryotherapy (WBC) session performed shortly after repeated sprint exercise were investigated. In a randomized, counterbalanced, and crossover design, 14 habituated English Premier League academy soccer players performed 15 × 30 m sprints (each followed by a 10 m forced deceleration) on 2 occasions. Within 20 minutes of exercise cessation, players entered a WBC chamber (Cryo: 30 seconds at -60° C, 120 seconds at -135° C) or remained seated (Con) indoors in temperate conditions (∼25° C). Blood and saliva samples, peak power output (countermovement jump), and perceptual indices of recovery and soreness were assessed pre-exercise and immediately, 2-hour and 24-hour postexercise. When compared with Con, a greater testosterone response was observed at 2-hour (+32.5 ± 32.3 pg·ml, +21%) and 24-hour (+50.4 ± 48.9 pg·ml, +28%) postexercise (both P = 0.002) in Cryo (trial × treatment interaction: P = 0.001). No between-trial differences were observed for other salivary (cortisol and testosterone/cortisol ratio), blood (lactate and creatine kinase), performance (peak power output), or perceptual (recovery or soreness) markers (all trial × treatment interactions: P > 0.05); all of which were influenced by exercise (time effects: all P ≤ 0.05). A single session of WBC performed within 20 minutes of repeated sprint exercise elevated testosterone concentrations for 24 hours but did not affect any other performance, physiological, or perceptual measurements taken. Although unclear, WBC may be efficacious for professional soccer players during congested fixture periods.

Skill acquisition and stress adaptations following laparoscopic surgery training and detraining in novice surgeons.

BACKGROUND: Surgical training and practice is stressful, but adaptive changes in the stress circuitry (e.g. perceptual, physiological, hormonal, neural) could support skill development. This work examined skill acquisition and stress adaptations in novice surgeons during laparoscopic surgery (LS) training and detraining. METHODS: Twelve medical students were assessed for skill performance after 2 h (BASE), 5 h (MID) and 8 h (POST) of LS training in weeks 1-3, and then after 4 weeks of no training (RETEST). The stress outcomes included state anxiety, perceived stress and workload, heart rate (HR), heart rate variability (HRV), and salivary testosterone and cortisol concentrations. Functional near-infrared spectroscopy was used to assess cortical oxygenation change, as a marker of prefrontal cortex (PFC) activity. RESULTS: Skill performance improved in every session from BASE (p < 0.01), with corresponding decreases in state anxiety, stress, workload, low- and high-frequency HRV in the MID, POST and/or RETEST sessions (p < 0.05). Left and right PFC were symmetrically activated within each testing session (p < 0.01). The stress and workload measures predicted skill performance and changes over time (p < 0.05), with state anxiety, mean HR and the HRV measures also showing some predictive potential (p < 0.10). CONCLUSIONS: A 3-week LS training programme promoted stress-related adaptations likely to directly, or indirectly, support the acquisition of new surgical skills, and many outcomes were retained after a 4-week period without further LS training. These results have implications for medical training and education (e.g. distributed training for skill development and maintenance, stress resource and management training) and highlighted possible areas for new research (e.g. longitudinal stress and skill profiling).

Relationship between midweek training measures of testosterone and cortisol concentrations and game outcome in professional rugby union matches.

The aim of this study was to assess the response of salivary-free testosterone and cortisol concentrations across selected midweek skill-based training sessions and their association with subsequent match outcome 3 days later. Twenty-two rugby union players were assessed for salivary-free testosterone and cortisol concentrations before and after a midweek training session over 6 consecutive weeks. The relative percentage change (response) in the testosterone and cortisol concentration and the testosterone to cortisol (T/C) ratio was also determined. Game-day analysis consisted of prematch testosterone concentrations and match outcome. Data were pooled across the winning (n = 3) and losing (n = 3) outcomes. The midweek pretraining T/C ratio was significantly lower (p < 0.01) before a win than a loss and the increase in the pre- to post-T/C ratio before a win was significant (p < 0.001). The increase in the pre- to post-testosterone concentration before a win was also shown to be significant (p < 0.01). However, the relative changes in testosterone before games that were won were not statistically different to that of games lost (p > 0.01). Significant relationships were also demonstrated between game-day pre-testosterone concentrations and the midweek cortisol response (r = -0.90, p = 0.01) and midweek T/C ratio response (r = 0.90, p = 0.01). In conclusion, a midweek measurement of the T/C ratio against a skill-based training session seems to show some potential as an early indicator of subsequent successfully executed performances in competitive rugby union. If this work is subsequently validated, further monitoring of midweek hormone concentrations in response to a mixed psychological-physical training session may assist with assessing competitive readiness leading up to competition.

The metabolic, hormonal, biochemical, and neuromuscular function responses to a backward sled drag training session.

We examined the metabolic, hormonal, biochemical, and neuromuscular function (NMF) responses to a backward sled drag training session (STS) in strength-trained men (n = 11). After baseline collection of saliva (testosterone and cortisol), whole blood (lactate and creatine kinase [CK]), and countermovement jumps (peak power output), participants completed 5 sets of 2 × 20-m (30 second-recovery between drags and 120 second-recovery between sets) maximal backward sled drags (loaded with 75% body mass). Participants were retested immediately, 15 minutes, 1, 3, and 24 hours after STS. Peak power output decreased after STS (baseline, 4,445 ± 705 vs. 0 minute, 3,464 ± 819 W; p = 0.001) and remained below baseline until recovering at both the 3- and 24-hour time points. No changes in CK levels were seen at any time point after STS. Blood lactate increased immediately after STS (baseline, 1.7 ± 0.5 vs. 0 minute, 12.4 ± 2.6 mmol·L-1; p = 0.001) and remained elevated at 60 minutes (3.8 ± 1.9 mmol·L-1; p = 0.004) before returning to baseline at 3 and 24 hours. Testosterone peaked at 15 minutes post (baseline, 158 ± 45 vs. 15 minutes, 217 ± 49 pg·ml-1; p < 0.001) before decreasing below baseline at the 3-hour time point (119 ± 34 pg·ml-1; p = 0.008), but then increased again above baseline at 24 hours (187 ± 56 pg·ml-1; p = 0.04). Cortisol tended to increase at 15 minutes (baseline, 3.4 ± 1.8 vs. 15 minutes, 5.2 ± 2.7 ng·ml-1; p = 0.07) before declining below baseline at 3 hours (1.64 ± 0.93 ng·ml-1; p = 0.012) and returning to baseline concentrations at 24 hours. In conclusion, sled dragging provides an effective metabolic stimulus, with NMF restored after ≤3 hours of recovery. Characterizing the recovery time course after sled training may aid in athlete training program design.

Neuromuscular function, hormonal, and mood responses to a professional rugby union match.

We examined the recovery time-course of neuromuscular function (NMF), the testosterone and cortisol hormonal milieu, and mood for 60 hours after a competitive match in professional rugby union players (n = 14). Thirty-six hours prematch (19:30 hours kick-off), baseline saliva samples (testosterone, cortisol, and testosterone to cortisol [T/C] ratio), countermovement jump performances (peak power output [PPO]), and mood disruption (Brief Assessment of Mood Questionnaire) were collected and was repeated at 12, 36, and 60 hours postmatch. Peak power output decreased below baseline at 12 hours (baseline 6,100 ± 565 W vs. 12 h 5,680 ± 589 W; p = 0.004) and 36 hours (5,761 ± 639 W; p < 0.001) but had recovered at 60 hours (5,950 ± 505 W; p = 0.151). Cortisol concentrations increased from baseline at 12 hours (baseline 0.40 ± 0.09 µg·dl-1 vs. 12 h 0.60 ± 0.20 µg·dl-1; p = 0.004) and 36 hours (0.60 ± 0.20 µg·dl-1; p = 0.027) but were similar at 60 hours postmatch. Testosterone concentrations decreased from baseline at 12 hours (baseline 214 ± 84 pg·ml-1 vs. 12 h 151 ± 56 pg·ml-1; p = 0.023) and 36 hours (173 ± 71 pg·ml-1; p = 0.016) but were similar at 60 hours postmatch. The T/C ratio decreased from baseline at 12 hours (baseline 551 ± 219 vs. 12 h 266 ± 123; p = 0.001) and 36 hours (310 ± 148; p = 0.027) before returning to baseline at 60 hours postmatch. Mood disturbance increased at 12 hours (p = 0.031) before returning to baseline at 36 and 60 hours postmatch. There were no relationships between changes in PPO, testosterone, cortisol, T/C ratio, and mood. In conclusion, postmatch changes in NMF, salivary hormones, and mood disturbance were identified in professional rugby union players. Players and coaches can expect reduced NMF and hormonal disruption for 36 hours before recovering at 60 hours postmatch, with mood recovered by 36 hours postmatch. Knowledge of these recovery time-courses may prove useful for player training program design and postmatch recovery strategies.

Right-left digit ratio (2D:4D) predicts free testosterone levels associated with a physical challenge.

There is evidence that the digit ratio (2D:4D) is a negative correlate of prenatal levels of testosterone, but there is no association between 2D:4D and the circulating levels of both total and free testosterone. Sports provide a physical challenge and participants often show increased levels of free testosterone immediately preceding and during competition. We tested this hypothesis of a link between 2D:4D and testosterone under challenge in 79 professional rugby players using the following procedures; (i) 25 players were physically challenged using a repeated sprint agility test, and saliva samples were assayed for testosterone immediately preceding the repeated sprint agility test (time 1) and 5 minutes (time 2) and 20 minutes after completion of the repeated sprint ability (time 3); (ii) 54 players were also tested for salivary testosterone in an unchallenged condition. We found that right-left 2D:4D was significantly and negatively related to testosterone concentrations at times 1, 2 and 3 following the repeated sprint agility test (P < 0.05) and there was no association between the 2D:4D and basal testosterone levels in the unchallenged group. We suggest that low right-left 2D:4D is a predictive marker of free testosterone responsiveness when trained men are physically challenged, and that this association is programmed by the action of prenatal testosterone.

The workout responses of salivary-free testosterone and cortisol concentrations and their association with the subsequent competition outcomes in professional rugby league.

This study assessed the responses of salivary-free testosterone (T) and cortisol (C) concentrations across selected training workouts and their association with the subsequent competition outcomes in professional rugby league. Thirteen rugby league players were assessed for salivary-free T and C concentrations across 5 training workouts performed 3-4 days before a competitive game. The game outcomes included wins and losses and game-ranked performance (1-5) based on the number of points scored, the points differential, and a coach rating. Data were pooled across the winning (n = 3) and losing (n = 2) outcomes. Pooled free T concentrations (absolute and relative changes) were significantly (p < 0.01) elevated across those workouts that preceded winning games, but not the losses, and the relative (percent) T changes were significantly (p < 0.05) higher before winning (30.9%) than before losing (3.4%). Both outcomes were associated with workout decreases in pooled free C concentrations and the relative C changes were not significantly different between wins (-22.9%) and losses (-25.6%). In conclusion, the free T responses to selected training workouts showed some association with subsequent winning (being elevated) and losing (no change) during a limited number of competitive games in professional rugby league. Speculatively, the free T responses to a midweek workout might provide an early sign of team readiness to compete or to recovery state, thereby providing a novel format for implementing training or management strategies to improve the competition outcomes.

Mental Rehearsal Improves Passing Skill and Stress Resilience in Rugby Players.

PURPOSE: Mental rehearsal is commonly employed, with positive visualization proposed to enhance complex skill performance. Additionally, video stimulus has been associated with enhanced kinesthetic sensations and rapid hormone fluctuations that may contribute to enhancing mental rehearsal and the conscious and unconscious emotional state for skill execution. Here, we assessed the impact of a 15-minute mental rehearsal intervention on rugby-specific tasks and the associated hormone profile. METHODS: Professional rugby players (N = 10) volunteered for a randomized crossover study. They completed three 15-minute preparatory phases (positive or negative video-guided mental rehearsal or self-directed mental rehearsal alone) prior to an exercise stressor and rugby-specific passing task. Salivary testosterone and cortisol were monitored to assess stress responses. RESULTS: Performance during the rugby passing task was improved following the positive video condition (91% [7.4%]) compared to the negative video (79% [6.0%]; ES: 1.22 ± 0.75) and self-visualization (86% [5.8%]; ES: 0.58 ± 0.75), with a significant correlation observed between passing performance and salivary testosterone (r = .47 ± .34, P = .0087). Positive video imagery prior to an exercise stressor also significantly enhanced physiological stress resilience (r = .39 ± .36, P = .0352). CONCLUSIONS: This pilot study demonstrates that mental rehearsal was enhanced by appropriate, context-specific video presentation. We propose that the interaction between sex steroids, the adrenal axis, and subsequent conscious and unconscious behaviors may be relevant to competitive rugby. Specifically, we suggest that relatively elevated free testosterone imparts a degree of stress resilience, which may lead to enhanced expression of competitive behaviors and provide an enhanced state for rugby skill execution.

Changes in salivary testosterone concentrations and subsequent voluntary squat performance following the presentation of short video clips.

Previous studies have shown that visual images can produce rapid changes in testosterone concentrations. We explored the acute effects of video clips on salivary testosterone and cortisol concentrations and subsequent voluntary squat performance in highly trained male athletes (n=12). Saliva samples were collected on 6 occasions immediately before and 15 min after watching a brief video clip (approximately 4 min in duration) on a computer screen. The watching of a sad, erotic, aggressive, training motivational, humorous or a neutral control clip was randomised. Subjects then performed a squat workout aimed at producing a 3 repetition maximum (3RM) lift. Significant (P<0.001) relative (%) increases in testosterone concentrations were noted with watching the erotic, humorous, aggressive and training videos (versus control and sad), with testosterone decreasing significantly (versus control) after the sad clip. The aggressive video also produced an elevated cortisol response (% change) and more so than the control and humorous videos (P<0.001). A significant (P<0.003) improvement in 3RM performance was noted after the erotic, aggressive and training clips (versus control). A strong within-individual correlation (mean r=0.85) was also noted between the relative changes in testosterone and the 3RM squats across all video sessions (P<0.001). In conclusion, different video clips were associated with different changes in salivary free hormone concentrations and the relative changes in testosterone closely mapped 3RM squat performance in a group of highly trained males. Thus, speculatively, using short video presentations in the pre-workout environment offers an opportunity for understanding the outcomes of hormonal change, athlete behaviour and subsequent voluntary performance.

Comparison of baseline free testosterone and cortisol concentrations between elite and non-elite female athletes.

OBJECTIVES: To compare the baseline free testosterone (T) and cortisol (C) concentrations of elite and non-elite female athletes. METHODS: Eighteen females from different sports (track and field, netball, cycling, swimming, bob skeleton) were monitored over a 12-week period. Baseline measures of salivary free T and C concentrations were taken weekly prior to any training. The elites (n = 9) and non-elites (n = 9) were classified as international and national level competitors, respectively, with both groups matched by sport. RESULTS: The pooled free T concentrations of the elites (87 pg/ml) were significantly higher than the non-elites (41 pg/ml) and consistently so across all weekly time points (P < 0.001). Pooled free C concentrations were also greater in the elite group (2.90 ng/ml) than the non-elites (2.32 ng/ml) (P < 0.01). CONCLUSIONS: The pooled baseline T and C measures were higher in elite female athletes than non-elites. Higher free T and C concentrations could indicate a greater capacity for physical performance at higher work rates, which is commensurate with the demands of elite sport. Speculatively, the T differences observed could influence female behavior and thereby help to regulate sporting potential.

Baseline strength can influence the ability of salivary free testosterone to predict squat and sprinting performance.

The objective of this study was to determine if salivary free testosterone can predict an athlete's performance during back squats and sprints over time and the influence baseline strength on this relationship. Ten weight-trained male athletes were divided into 2 groups based on their 1 repetition maximum (1RM) squats, good squatters (1RM > 2.0 × body weight, n = 5) and average squatters (1RM < 1.9 × body weight, n = 5). The good squatters were stronger than the average squatters (p < 0.05). Each subject was assessed for squat 1RM and 10-m sprint times on 10 separate occasions over a 40-day period. A saliva sample was collected before testing and assayed for free testosterone and cortisol. The pooled testosterone correlations were strong and significant in the good squatters (r = 0.92 for squats, r = -0.87 for sprints, p < 0.01), but not significant for the average squatters (r = 0.35 for squats, r = -0.18 for sprints). Cortisol showed no significant correlations with 1RM squat and 10-m sprint performance, and no differences were identified between the 2 squatting groups. In summary, these results suggest that free testosterone is a strong individual predictor of squat and sprinting performance in individuals with relatively high strength levels but a poor predictor in less strong individuals. This information can assist coaches, trainers, and performance scientists working with stronger weight-trained athletes, for example, the preworkout measurement of free testosterone could indicate likely training outcomes or a readiness to train at a certain intensity level, especially if real-time measurements are made. Our results also highlight the need to separate group and individual hormonal data during the repeated testing of athletes with variable strength levels.

Acute physiological and perceptual responses to a netball specific training session in professional female netball players.

The 24 h responses to professional female netball-specific training were examined. British Superleague players (n = 14) undertook a 90-min on-court training session incorporating key movement, technical, and scenario-specific match-play drills. Perceptual (mood, fatigue, soreness), neuromuscular (countermovement jump peak power output [PPO], PPO relative to mass [PPOrel], jump height [JH]), endocrine (salivary cortisol [C], testosterone [T] concentrations) and biochemical (creatine kinase concentrations [CK]) markers were assessed at baseline (immediately before; Pre), and immediately, two and 24 hours after (+0h, +2h, +24h) training. Session (sRPE) and differential (dRPE) ratings of perceived exertion were recorded at +0h. Identification of clear between time-point differences were based on the 95% confidence interval (CI) for mean differences relative to baseline values not overlapping. At +0h, C (raw unit mean difference from baseline; 95% CI: 0.16; 0.06 to 0.25 µg·dl-1), T (32; 20 to 45 pg⋅ml-1), CK (39; 28 to 50 u·L-1), PPOrel (2.4; 0.9 to 3.9 W·kg-1) and PPO (169; 52 to 286 W) increased. At +2h, fatigue (15; 7 to 24 AU), CK (49; 38 to 60 u·L-1), and soreness (14; 3 to 25 AU) increased, while T (-24; -37 to -11 pg⋅ml-1) and mood (-20; -27 to -12 AU) reduced. At +24h, CK increased (25; 13 to 36 u·L-1) whereas PPOrel (-1.6; -3.2 to -0.1 W·kg-1) and JH (-0.02; -0.03 to -0.08 m) reduced. Responses were variable specific, and recovery of all variables did not occur within 24h. The residual effects of the prior stimulus should be accounted for in the planning of training for professional female netball players.

The effects of short-cycle sprints on power, strength, and salivary hormones in elite rugby players.

This study examined the effects of short-cycle sprints on power, strength, and salivary hormones in elite rugby players. Thirty male rugby players performed an upper-body power and lower-body strength (UPLS) and/or a lower-body power and upper-body strength (LPUS) workout using a crossover design (sprint vs. control). A 40-second upper-body or lower-body cycle sprint was performed before the UPLS and LPUS workouts, respectively, with the control sessions performed without the sprints. Bench throw (BT) power and box squat (BS) 1 repetition maximum (1RM) strength were assessed in the UPLS workout, and squat jump (SJ) power and bench press (BP) 1RM strength were assessed in the LPUS workout. Saliva was collected across each workout and assayed for testosterone (Sal-T) and cortisol (Sal-C). The cycle sprints improved BS (2.6 ± 1.2%) and BP (2.8 ± 1.0%) 1RM but did not affect BT and SJ power. The lower-body cycle sprint produced a favorable environment for the BS by elevating Sal-T concentrations. The upper-body cycle sprint had no hormonal effect, but the workout differences (%) in Sal-T (r = -0.59) and Sal-C (r = 0.42) concentrations correlated to the BP, along with the Sal-T/C ratio (r = -0.49 to -0.66). In conclusion, the cycle sprints improved the BP and BS 1RM strength of elite rugby players but not power output in the current format. The improvements noted may be explained, in part, by the changes in absolute or relative hormone concentrations. These findings have practical implications for prescribing warm-up and training exercises.