Serum cortisol as a moderator of the relationship between serum testosterone and Olympic weightlifting performance in real and simulated competitions

Associations between the Big Five personality traits, testosterone, and cortisol in adolescent male athletes

Testosterone (T) has been conceptualized as a biomarker of individual differences, yet T associations with the Big Five personality traits are inconsistent. Athletes provide a suitable model for evaluation here, as T co-expresses traits related to male-to-male competition and fitness with cortisol (C) playing a moderating role. This study investigated associations between the Big Five traits, T, and C in adolescent male athletes. One hundred and twenty male ice hockey players (aged 14-19 years) were assessed for blood total (T, C) and free (FT, FC) hormones, body-size dimensions (i.e., body mass, height, body mass index [BMI]), the Big Five personality traits (i.e., extraversion, neuroticism, agreeableness, conscientiousness, openness), and trait anxiety. Correlational and regression (with age and BMI as covariates) analyses identified a positive effect of FT on extraversion, but a negative FT effect on neuroticism and anxiety (p < 0.05). Significant FT × FC interactions emerged for extraversion and agreeableness. Slope testing revealed that FT had a positive effect on extraversion at the FC mean and +1 SD, and a negative effect on agreeableness with FC at +1 SD. In conclusion, adolescent male athletes with a higher serum FT concentration tended to express higher extraversion, but lower neuroticism and anxiety. The FT association with extraversion was moderated by FC concentration, as was agreeableness. Therefore, high-FT athletes presented a behavioural disposition that favours dominance and resiliency, with some dependencies on FC availability. Since all association effect sizes were weak, replicate studies on larger adolescent samples are needed.

Criteria for assessing the adaptive changes in mixed martial arts (MMA) athletes of strike fighting style in different training load regimes

Background

To study the peculiarities of changes in functional indicators and body composition parameters of mixed martial arts (MMA) athletes of strike fighting style and a number of biochemical blood indicators during two months of using different intensity training load regimes, and to determine the most informative criteria for assessing adaptive body changes in these training conditions.

Methods

We examined 40 MMA athletes (men) aged 20-22, who used mainly strike fighting style in their competitive activity, and divided them into 2 research groups (A and B), 20 athletes in each group. Group A athletes used medium intensity (R _a  = 0.64), and group B-high intensity (R _a  = 0.72) training load regime. To assess the adaptive body changes we applied methods of control testing of maximum muscle strength growth (1 RM), special training (the number of accurate kicks on the mannequin for 30 s), and bioimpedansometry. By monitoring biochemical parameters (testosterone, cortisol, creatinine, phosphorus, calcium, cholesterol, LDH) in the blood serum of athletes, we determined the peculiarities of adaptive-compensatory body reactions in response to training loads.

Results

The obtained results of special training increased during the study period by an average of 10.5% in group B athletes, but group A participants' results had no significant changes compared to basal data. The largest increase in the development of maximum muscle strength growth by an average of 44.4% was recorded after 2 months of research in group B. Group B athletes also had positive changes in body fat and fat-free mass indicators during the study which were two times higher than the results of group A. The laboratory studies and correlation analysis showed informative biochemical markers (cortisol, testosterone and creatinine) for assessing the condition of athletes in both groups before using high and medium training load regimes. The biochemical markers for assessing the adaptive-compensatory reactions of athletes in response to high-intensity physical stimuli at the beginning of the study were indicators of LDH and cholesterol, and in conditions of medium intensity it was LDH, testosterone and cortisol. After 2 months of study the set of biochemical markers assessing the adaptation processes before the load completely changed only in group B athletes and consisted of LDH, phosphorus, cholesterol, and calcium. At the same time, the set of biochemical criteria for assessing adaptive-compensatory reactions after training in group B athletes was completely changed compared with the data recorded at the beginning of the study.

Conclusion

Defining the optimal set of criteria for assessing the adaptive-compensatory changes in MMA athletes of strike fighting style will allow in the shortest possible time to correct the parameters of the training load regime for accelerating the body functionality in the process of special power training.

The gonadal response to social stress and its relationship to cortisol

The cortisol response to social evaluative stress has been well characterized. However, data regarding changes in gonadal hormones after stress are still scarce and inconsistent. The majority of studies have focused on testosterone reactivity to stress in men, while estradiol responses or gonadal stress responses in women have hardly been investigated. Furthermore, it has not been evaluated whether sex hormone reactivity to stress differs between men and women and the relationship between cortisol and gonadal reactivity to stress is still unclear. To address these questions, we re-analyzed saliva samples collected from 37 men and 30 women in their luteal cycle phase before and repeatedly after social-evaluative stress. Both, testosterone and estradiol levels were assessed. In both men and women, testosterone was significantly reduced after stress. Testosterone levels were at their lowest after 20 minutes, but did not return to baseline until 35 minutes after stress. Across the whole sample, estradiol was significantly increased after stress with two separate peaks after 15 and 30 minutes. Follow-up analyses revealed that 41 participants actually responded with a decrease in estradiol levels to stress, with lowest levels after 20 min, while the remaining participants responded with an increase in estradiol levels. These gonadal stress responses appear to be largely independent of the cortisol response to stress. These results demonstrate that the endocrinological stress response is not restricted to the HPA axis and stress responsivity of gonadal hormones is not simply driven by cortisol. Accordingly, the stress responsivity of gonadal hormones and their association to psychological variables is an additional avenue to explore in both men and women.

The neuromuscular, physiological, endocrine and perceptual responses to different training session orders in international female netball players

AbstractThe 20 h responses of International female netball players to training days requiring two sessions (netball and strength, separated by two hours) ordered alternatively were examined. Eleven players completed strength followed by netball training two hours later (STR-NET), with the order reversed (NET-STR) on a separate day. Well-being, neuromuscular performance (jump height [JH], peak power output [PPO], peak velocity [PV]) and endocrine function (testosterone, cortisol concentrations) were measured before sessions one (PreS1) and two (PreS2), immediately after sessions one (IPS1) and two (IPS2), and 20 h post session one (20P). Session and differential ratings of perceived exertion (upper-body, cognitive/technical [RPE-T], lower-body, breathlessness) were collected, and accelerometry and heart rate measured netball load. Identification of clear between-order differences was based on the nonoverlap of the 95% confidence interval (95%CI) for mean differences relative to baseline. Compared to PreS1, greater increases in JH (percentage difference between trials; 95%CI: 9%; 4-14%), PPO (5%; 2-8%), PV (3%; 1-5%) and cortisol concentration (45%; 1-88%), and a greater decrease for testosterone/cortisol ratio (-35%; -72 to -2%) occurred at PreS2 in NET-STR. At 20P, greater decreases in JH (10%; 5-15%), PPO (4%; 1-8%) and PV (4%; 2-6%) were observed following STR-NET. No differences existed for well-being, whilst RPE-T was greater (15 AU; 3-26 AU) for strength training during NET-STR. Session order influenced neuromuscular and endocrine responses in International female netball players, highlighting session ordering as a key consideration when planning training.

Vitamin D and Cortisol as Moderators of the Relationship Between Testosterone and Exercise Performance in Adolescent Male Athletes

PURPOSE

Reported associations between vitamin 25(OH)D and exercise performance are equivocal, perhaps due to complex interplay with cortisol and testosterone. In this study, the authors investigated serum 25(OH)D and cortisol as moderators of the testosterone relationship with exercise performance in adolescent male athletes.

METHODS

A total of 88 ice hockey players were assessed for serum 25(OH)D, cortisol, testosterone, body composition, and exercise performance, based on countermovement jump power and muscle torque. The authors tested independent relationships, before examining complex interactions via moderated regression analyses.

RESULTS

Most athletes (62.5%) exhibited a suboptimal (20-30 ng·mL-1) serum 25(OH)D concentration, whereas 9.1% of athletes were deficient (<20 ng·mL-1). Serum 25(OH)D was not related to performance when controlling for testing year, age, and fat mass. Further modeling revealed a significant hormonal interaction. Specifically, in low-25(OH)D subjects, testosterone predicted countermovement jump power at a high (β = 7.10, effect size = .43, P < .01), but not low (β = -3.32, effect size = -.20, P = .09), cortisol concentration.

CONCLUSIONS

Serum 25(OH)D was a poor predictor of exercise performance, but it did moderate (with cortisol) the testosterone link to muscle power. Notably, this relationship emerged among individuals with a 25(OH)D concentration (∼22 ng·mL-1) approaching the deficiency cutoff. Viewing 25(OH)D as a moderating, rather than dose responsive, variable could help explain equivocal cross-sectional associations.

Beyond the challenge hypothesis: The emergence of the dual-hormone hypothesis and recommendations for future research

The challenge hypothesis makes specific predictions about the association between testosterone and status-seeking behaviors, but the findings linking testosterone to these behaviors are often inconsistent. The dual-hormone hypothesis was developed to help explain these inconsistencies. Specifically, according to this hypothesis, testosterone's association with status-seeking behavior depends on levels of cortisol. Here, we (1) describe the dual-hormone hypothesis in relation to the challenge hypothesis; (2) review recent studies that tested the dual-hormone hypothesis as well as meta-scientific evidence of heterogeneous dual-hormone findings across studies; (3) discuss potential explanations for this heterogeneity, including methodological considerations, contextual factors, and individual differences; and (4) provide recommendations for new work aimed at testing and extending the dual-hormone hypothesis.

Does stress affect nonverbal engagement in teams? A case study in professional team sport

Purpose

Team effectiveness is often predicated by a group’s ability to communicate. However, the effect of stress response on communication success, particularly nonverbal engagement, and how this might affect team performance, is not clear; a “phenomenon” this study sought to explore.

Design/methodology/approach

This was an observational study in a cohort of professional rugby players. Participants gave presentations to their peers on two separate occasions during a “live-in” camp designed to have psychologically stressful elements. Presentations were video recorded and audience engagement was measured. Testosterone and cortisol were used as biomarkers of stress response, with a high testosterone–cortisol ratio considered positive. A team training session followed the presentations and participants were rated for training quality.

Findings

A small decline in testosterone was observed each day after waking. Conversely, cortisol rose after waking, with the rise being the highest on the first day. A decline in testosterone–cortisol ratio was also seen each day after waking; the decline was greatest on the first day. Presentation duration and audience engagement was greatest for the second presentation; when the testosterone-cortisol ratio decline and the cortisol increase after waking was smaller. Training quality was also better that day. Pooled data revealed a moderate inverse relationship and weak positive relationships for audience engagement with post-meeting cortisol and post-meeting testosterone–cortisol ratio, respectively. Training quality was related to testosterone and testosterone–cortisol ratio, but inversely related to cortisol.

Originality/value

This study suggests that in stressful conditions, as suggested by an awakening hormone response, communication and team performance could become compromised with reduced ability to engage with others.

Individual variation in the cortisol response to a simulated Olympic weightlifting competition is related to changes in future competitive performance

The cortisol (C) and testosterone (T) responses to experimental stress have been linked to sport and health outcomes several days to years later. Here we examined the utility of these biomarkers, taken across a simulated Olympic weightlifting (OWL) competition, as predictors of future competitive performance in young athletes. Seventy junior athletes (46 males, 24 females) participated in a talent identification and development programme that replicated an OWL competition. Performance was indexed by the total load lifted, relative to body mass, with serum changes in C (∆C) and (∆T) concentrations profiled. We identified each athlete’s best performance in real competitions over two subsequent years via online resources. Hierarchical regression was used to predict changes in competitive performance at <12 (∆Total12) and 12-24 months (∆Total24). The simulated OWL event promoted a small positive ∆C (effect size [ES]=0.3) and ∆T (ES=0.5), but with large variation in ∆C (-58% to 200%) and ∆T (-21% to 71%). Performance improved after 12 (ES=1.5) and 24 months (ES=0.9). The ∆C was negatively related to the ∆Total12 and ∆Total24 when controlling for competitions entered (R²=13-24%). Sensitivity analyses confirmed the ∆C link to both outcomes (R²=9%). The serum C and T responses to a simulated OWL competition varied considerably between participants. Their competitive performance improved over the next two years and individual performance trajectories were related to the ∆C. Therefore, individual variation in the C responses to a competitive stressor may help forecast the training and/or competitive gain process in young developing athletes.