Are There Useful Physiological or Psychological Markers for Monitoring Overload Training in Elite Rowers?

Competition Stress Leads to a Blunting of the Cortisol Awakening Response in Elite Rowers

Background: Anticipation of forthcoming demands is often met with biological up-regulation, for example, levels of the stress hormone cortisol are typically elevated immediately prior to an anticipated event. Similarly, the cortisol awakening response (CAR), a surge in cortisol in the period following waking, is elevated on days of anticipated demand and this is viewed as an adaptive response in the preparation for challenge. This study assessed the effects of competition as an anticipated challenge in elite rowers. Methods: Elite rowers (N = 8) were assessed during two training and two competition weekends. Each assessment involved the measurement of self-reported competitive (cognitive and somatic) anxiety and salivary diurnal cortisol across 2 days representing a preparation day prior to either a training or competition day. Competitive anxiety was measured each morning and saliva samples were provided immediately upon waking and 30 min post waking (CAR) and before bed. Results: Self-reported cognitive and somatic anxiety levels were significantly greater during the competition phase compared with training. Additionally, levels of cognitive anxiety were greater on the day of competition compared with the preparation day. CAR magnitude was significantly reduced during the competition phase compared with training; however, there were no differences between preparation and event days. Conclusions: Reduced or blunted CARs are typically observed in chronically stressed populations and are characteristic of burnout and fatigue. While an increased CAR during competition may represent an adaptive response to challenge, blunted CARs and the concomitant increases in competitive anxiety observed here indicate maladaptive responding during a period where maximized functioning is critical.

Biomarkers of Physiological Responses to Periods of Intensified, Non-Resistance-Based Exercise Training in Well-Trained Male Athletes: A Systematic Review and Meta-Analysis

BACKGROUND

Intensified training is important for inducing adaptations to improve athletic performance, but detrimental performance effects can occur if prescribed inappropriately. Monitoring biomarker responses to training may inform changes in training load to optimize performance.

OBJECTIVE

This systematic review and meta-analysis aimed to identify biomarkers associated with altered exercise performance following intensified training.

METHODS

Embase, MEDLINE, CINAHL, Scopus and SPORTDiscus were searched up until September 2017. Included articles were peer reviewed and reported on biomarkers collected at rest in well-trained male athletes before and after periods of intensified training.

RESULTS

The full text of 161 articles was reviewed, with 59 included (708 participants) and 42 (550 participants) meta-analysed. In total, 118 biomarkers were evaluated, with most being cellular communication and immunity markers (n = 54). Studies most frequently measured cortisol (n = 34), creatine kinase (n = 25) and testosterone (n = 20). Many studies reported decreased immune cell counts following intensified training, irrespective of performance. Moreover, reduced performance was associated with a decrease in neutrophils (d = - 0.57; 95% confidence interval (CI) - 1.07 to - 0.07) and glutamine (d = - 0.37; 95% CI - 0.43 to - 0.31) and an increase in urea concentration (d = 0.80; 95% CI 0.30 to 1.30). In contrast, increased performance was associated with an increased testosterone:cortisol ratio (d = 0.89; 95% CI 0.54 to 1.24). All remaining biomarkers showed no consistent patterns of change with performance.

CONCLUSIONS

Many biomarkers were altered with intensified training but not in a manner related to changes in exercise performance. Neutrophils, glutamine, urea and the testosterone:cortisol ratio exhibited some evidence of directional changes that corresponded with performance changes therefore indicating potential to track performance. Additional investigations of the potential for these markers to track altered performance are warranted.

Bouts of exercise elicit discordant testosterone: cortisol ratios in runners and non-runners

OBJECTIVE

The testosterone:cortisol ratio (T:C) is suggested to be used in order to examine whether physical exercise generates either a "catabolic environment" or an "anabolic environment". The present study aims to evaluate the acute time-course profile of cortisol and testosterone due to an episode of physical exercise. A biphasic profile in the T:C ratio response was hypothesized.

MATERIALS AND METHODS

Morning sessions of treadmill running at two different intensities (Heart Rate at 65% and 80% of the maximum cardiac reserve) were performed by 6 male non-runners (NR) and 12 trained male runners (subdivided into trained runners T1 and T2). Cortisol and testosterone were measured in saliva. NR and T1 ran for 30 minutes at both intensities, and T2 ran for 46 minutes (± 4.1) at 65% and 42 minutes (± 3.5) at 80%.

RESULTS

In the 80% heart rate target, both groups of runners showed the biphasic time-profile, while the non-runners group did not. However, at the 65% level, none of the groups presented the hypothesized biphasic response.

CONCLUSIONS

A biphasic time-profile in the testosterone:cortisol ratio can be seen in short-bout, high intensity exercise (treadmill running) during the morning in men trained for this specific physical activity.

High intensity and reduced volume training attenuates stress and recovery levels in elite swimmers

This study investigated the effect of increased high-intensity interval training (HIT) at the expense of total training volume on the stress and recovery levels of elite swimmers. Forty-one elite swimmers participated in the study and were randomly assigned to either a HIT or a control group (CON). Eleven swimmers did not complete the questionnaires. For 12 weeks both groups trained ~12 h per week. The amount of HIT was ~5 h vs. 1 h, and total distance was ~17 km vs. ~35 km per week for HIT and CON, respectively. HIT was performed as 6-10 × 10-30 s maximal effort interspersed by 2-4 min of rest. The Recovery Stress Questionnaire - Sport was used to measure the swimmers' stress and recovery levels. After the 12 week intervention, the general stress level was 16.6% (2.6-30.7%; mean and 95% CI) lower and the general recovery level was 6.5% (0.7-12.4%) higher in HIT compared to the CON, after adjusting for baseline values. No significant effects could be observed in sports-specific stress or sports-specific recovery. The results indicate that increasing training intensity and reducing training volume for 12 weeks can reduce general stress and increase general recovery levels in competitive swimmers.