No variation of physical performance and perceived exertion after adrenal gland stimulation by synthetic ACTH (Synacthen) in cyclists.

There is anecdotal evidence that athletes use the banned substance Synacthen because of its perceived benefit with its associated rise in cortisol. To test the performance-enhancing effects of Synacthen, eight trained cyclists completed two, 2-day exercise sessions separated by 7-10 days. On the first day of each 2-day exercise session, subjects received either Synacthen (0.25 mg, TX) or placebo (PLA) injection. Performance was assessed by a 20-km time trial (TT) after a 90-min fatigue period on day 1 and without the fatiguing protocol on day 2. Plasma androgens and ACTH concentrations were measured during the exercise bouts as well as the rate of perceived exertion (RPE). Spot urines were analyzed for androgens and glucocorticoids quantification. Basal plasma hormones did not differ significantly between PLA and TX groups before and 24 h after the IM injection (P > 0.05). After TX injection, ACTH peaked at 30 min and hormone profiles were significantly different compared to the PLA trial (P < 0.001). RPE increased significantly in both groups as the exercise sessions progressed (P < 0.001) but was not influenced by treatment. The time to completion of the TT was not affected on both days by Synacthen treatment. In the present study, a single IM injection of synthetic ACTH did not improve either acute or subsequent cycling performance and did not influence perceived exertion. The investigated urinary hormones did not vary after treatment, reinforcing the difficulty for ACTH abuse detection.

Monitoring of the training load and recovery parameters in competitive swimmers

Nombreux sont les groupes de recherche qui se sont intéressés, ces dernières années, à la manière de monitorer l'entraînement des sportifs de haut niveau afin d'optimaliser le rendement de ce dernier tout en préservant la santé des athlètes. Un des problèmes cardinaux d'un entraînement sportif mal conduit est le syndrome du surentraînement. La définition du syndrome susmentionné proposée par Kreider et al. est celle qui est actuellement acceptée par le « European College of Sport Science » ainsi que par le « American College of Sports Medicine», à savoir : « An accumulation of training and/or non-training stress resulting in long-term decrement in performance capacity with or without related physiological and psychological signs and symptoms of maladaptation in which restoration of performance capacity may take several weeks or months. » « Une accumulation de stress lié, ou non, à l'entraînement, résultant en une diminution à long terme de la capacité de performance. Cette dernière est associée ou non avec des signes et des symptômes physiologiques et psychologiques d'inadaptation de l'athlète à l'entraînement. La restauration de ladite capacité de performance peut prendre plusieurs semaines ou mois. » Les recommandations actuelles, concernant le monitoring de l'entraînement et la détection précoce du syndrome du surentrainement, préconisent, entre autre, un suivi psychologique à l'aide de questionnaires (tel que le Profile of Mood State (POMS)), un suivi de la charge d'entraînement perçue par l'athlète (p.ex. avec la session rating of perceived exertion (RPE) method selon C. Foster), un suivi des performances des athlètes et des charges d'entraînement effectuées ainsi qu'un suivi des problèmes de santé (blessures et maladies). Le suivi de paramètres sanguins et hormonaux n'est pas recommandé d'une part pour des questions de coût et de faisabilité, d'autre part car la littérature scientifique n'a, jusqu'ici, pas été en mesure de dégager des évidences à ce sujet. A ce jour, peu d'études ont suivi ces paramètres de manière rigoureuse, sur une longue période et chez un nombre d'athlète important. Ceci est précisément le but de notre étude.

Combining heat stress and moderate hypoxia reduces cycling time to exhaustion without modifying neuromuscular fatigue characteristics.

PURPOSE: This study investigated the isolated and combined effects of heat [temperate (22 °C/30 % rH) vs. hot (35 °C/40 % rH)] and hypoxia [sea level (FiO2 0.21) vs. moderate altitude (FiO2 0.15)] on exercise capacity and neuromuscular fatigue characteristics. METHODS: Eleven physically active subjects cycled to exhaustion at constant workload (66 % of the power output associated with their maximal oxygen uptake in temperate conditions) in four different environmental conditions [temperate/sea level (control), hot/sea level (hot), temperate/moderate altitude (hypoxia) and hot/moderate altitude (hot + hypoxia)]. Torque and electromyography (EMG) responses following electrical stimulation of the tibial nerve (plantar-flexion; soleus) were recorded before and 5 min after exercise. RESULTS: Time to exhaustion was reduced (P < 0.05) in hot (-35 ± 15 %) or hypoxia (-36 ± 14 %) compared to control (61 ± 28 min), while hot + hypoxia (-51 ± 20 %) further compromised exercise capacity (P < 0.05). However, the effect of temperature or altitude on end-exercise core temperature (P = 0.089 and P = 0.070, respectively) and rating of perceived exertion (P > 0.05) did not reach significance. Maximal voluntary contraction torque, voluntary activation (twitch interpolation) and peak twitch torque decreased from pre- to post-exercise (-9 ± 1, -4 ± 1 and -6 ± 1 % all trials compounded, respectively; P < 0.05), with no effect of the temperature or altitude. M-wave amplitude and root mean square activity were reduced (P < 0.05) in hot compared to temperate conditions, while normalized maximal EMG activity did not change. Altitude had no effect on any measured parameters. CONCLUSION: Moderate hypoxia in combination with heat stress reduces cycling time to exhaustion without modifying neuromuscular fatigue characteristics. Impaired oxygen delivery or increased cardiovascular strain, increasing relative exercise intensity, may have also contributed to earlier exercise cessation.

Cardiorespiratory and Cardiac Autonomic Responses to 30-15 Intermittent Fitness Test in Team Sport Players

Buchheit, M, Al Haddad, H, Millet GP, Lepretre, PM, Newton, M, and Ahmaidi, S. Cardiorespiratory and cardiac autonomic responses to 30-15 Intermittent Fitness Test in team sport players. J Strength Cond Res 23(1): xxx-xxx, 2009-The 30-15 Intermittent Fitness Test (30-15IFT) is an attractive alternative to classic continuous incremental field tests for defining a reference velocity for interval training prescription in team sport athletes. The aim of the present study was to compare cardiorespiratory and autonomic responses to 30-15IFT with those observed during a standard continuous test (CT). In 20 team sport players (20.9 +/- 2.2 years), cardiopulmonary parameters were measured during exercise and for 10 minutes after both tests. Final running velocity, peak lactate ([La]peak), and rating of perceived exertion (RPE) were also measured. Parasympathetic function was assessed during the postexercise recovery phase via heart rate (HR) recovery time constant (HRRtau) and HR variability (HRV) vagal-related indices. At exhaustion, no difference was observed in peak oxygen uptake (&OV0312;o2peak), respiratory exchange ratio, HR, or RPE between 30-15IFT and CT. In contrast, 30-15IFT led to significantly higher minute ventilation, [La]peak, and final velocity than CT (p < 0.05 for all parameters). All maximal cardiorespiratory variables observed during both tests were moderately to well correlated (e.g., r = 0.76, p = 0.001 for &OV0312;o2peak). Regarding ventilatory thresholds (VThs), all cardiorespiratory measurements were similar and well correlated between the 2 tests. Parasympathetic function was lower after 30-15IFT than after CT, as indicated by significantly longer HHRtau (81.9 +/- 18.2 vs. 60.5 +/- 19.5 for 30-15IFT and CT, respectively, p < 0.001) and lower HRV vagal-related indices (i.e., the root mean square of successive R-R intervals differences [rMSSD]: 4.1 +/- 2.4 and 7.0 +/- 4.9 milliseconds, p < 0.05). In conclusion, the 30-15IFT is accurate for assessing VThs and &OV0312;o2peak, but it alters postexercise parasympathetic function more than a continuous incremental protocol.

Skeletal Muscle Mitochondrial Function and Fatigability in Older Adults.

BACKGROUND: Fatigability increases while the capacity for mitochondrial energy production tends to decrease significantly with age. Thus, diminished mitochondrial function may contribute to higher levels of fatigability in older adults. METHODS: The relationship between fatigability and skeletal muscle mitochondrial function was examined in 30 participants aged 78.5 ± 5.0 years (47% female, 93% white), with a body mass index of 25.9 ± 2.7 kg/m(2) and usual gait-speed of 1.2 ± 0.2 m/s. Fatigability was defined using rating of perceived exertion (6-20 point Borg scale) after a 5-minute treadmill walk at 0.72 m/s. Phosphocreatine recovery in the quadriceps was measured using (31)P magnetic resonance spectroscopy and images of the quadriceps were captured to calculate quadriceps volume. ATPmax (mM ATP/s) and oxidative capacity of the quadriceps (ATPmax·Quadriceps volume) were calculated. Peak aerobic capacity (VO2peak) was measured using a modified Balke protocol. RESULTS: ATPmax·Quadriceps volume was associated with VO2peak and was 162.61mM ATP·mL/s lower (p = .03) in those with high (rating of perceived exertion ≥10) versus low (rating of perceived exertion ≤9) fatigability. Participants with high fatigability required a significantly higher proportion of VO2peak to walk at 0.72 m/s compared with those with low fatigability (58.7 ± 19.4% vs 44.9 ± 13.2%, p < .05). After adjustment for age and sex, higher ATPmax was associated with lower odds of having high fatigability (odds ratio: 0.34, 95% CI: 0.11-1.01, p = .05). CONCLUSIONS: Lower capacity for oxidative phosphorylation in the quadriceps, perhaps by contributing to lower VO2peak, is associated with higher fatigability in older adults.

Anxiety and severity of illicit substance use in adolescence: Evaluating the mediating role of perceived coping styles

The purpose of this study was to examine whether coping styles (Active coping, Internal coping and Withdrawal coping) mediated the relationships between anxiety and severity of illicit substance use among a sample of 110 Swiss adolescents ages 12-19 (M=16.3, SD=1.66). The current study tested two competing models of anxiety on severity of illicit substance use. In the first model, we tested the direct effect of trait anxiety (STAI-Y anxiety score) on severity of illicit substance use (ADAD drug use severity rating), while in the second models we examined the mediating role of coping styles in the link between trait anxiety and severity of illicit substance use. Path models indicated that the associations between trait anxiety and severity of illicit substance use are partially mediated by active and withdrawal coping styles. Limitations of the findings and implications for prevention of substance use in adolescence are discussed.

Effect of a small dose of alcohol on the endurance performance of trained cyclists.

AIM: The aim of this study was to investigate the effect of an acute small ethanol (EtOH) dose (0.5 ml EtOH/kg fat-free mass, combined with carbohydrate) in a drink on endurance performance of trained cyclists. METHODS: Thirteen well-trained male cyclists took part in this study. A 60-min cycling endurance performance test (time trial) was performed in a calorimetric chamber after drinking an EtOH (30 +/- 1.8 ml) or a non-EtOH control (C) drink. RESULTS: Overall, EtOH induced a significant decrease in the average cycling power output (PO) (EtOH: 233 +/- 23 W versus C: 243 +/- 24 W, P < 0.01). The time course of mechanical PO showed an early decrease during the EtOH trial as compared to C (P < 0.01). Due to the lower PO, oxygen consumption, carbon dioxide production and glucose oxidation were significantly lower (P < 0.05) as compared to C. Relative to PO, heart rate response and ratings of perceived exertion (RPE) were increased by EtOH as compared to C (P < 0.05). In contrast, EtOH did not influence gross work efficiency, glycaemia and blood lactate concentration. CONCLUSIONS: These results show that the acute low dose of EtOH decreased endurance performance. An increase of cardio-vascular strain and psychobiological mechanisms may explain this decrease of endurance performance.

Mood and nonmood components of perceived stress and exacerbation of Crohn's disease.

BACKGROUND: Diverse psychological factors are involved in the pathophysiology of stress. In order to devise effective intervention strategies, it is important to elucidate which factors play the most important role in the association between psychological stress and exacerbation of Crohn's disease (CD). We hypothesized that the association between perceived stress and exacerbation of CD would remain after removal of mood and anxiety components, which are largely involved in stress perception. METHODS: In all, 468 adults with CD were recruited and followed in different hospitals and private practices of Switzerland for 18 months. At inclusion, patients completed the Perceived Stress Questionnaire and anxiety and depression were assessed using the Hospital Anxiety and Depression Scale. During the follow-up, gastroenterologists assessed whether patients presented with a CD exacerbation. By means of binary logistic regression analysis, we estimated the factor by which one standard deviation of perceived stress would increase the odds of exacerbation of CD with and without controlling for anxiety and depression. RESULTS: The odds of exacerbation of CD increased by 1.85 times (95% confidence interval 1.43-2.40, P < 0.001) for 1 standard deviation of perceived stress. After removing the anxiety and depression components, the residuals of perceived stress were no longer associated with exacerbation of CD. CONCLUSIONS: The association between perceived stress and exacerbation of CD was fully attributable to the mood components, specifically anxiety and depression. Future interventional studies should evaluate the treatment of anxiety and depression as a strategy for potential prevention of CD exacerbations.

Endocrine response and perceived stress test during an experimental challenge task in adult survivors of a childhood cancer.

BACKGROUND: Although long-term implications of cancer in childhood or adolescence with regard to medical conditions are well documented, the impact on mental health and on response to stress, which may be an indicator of psychological vulnerability, is not yet well understood. In this study, psychological and physiological responses to stress were examined.¦PROCEDURE: Fifty-three participants aged 18-39 years (n = 25 survivors of childhood or adolescence cancer, n = 28 controls) underwent an experimental stress test, the Trier Social Stress Test (TSST). Participants were asked to provide repeated evaluations of perceived stress on visual-analogical scales and blood samples were collected before and after the TSST to measure plasma cortisol.¦RESULTS: The psychological perception of stress was not different between the two groups. However, the cancer survivors group showed a higher global plasma cortisol level as well as higher amplitude in the response to the TSST. The global cortisol level in cancer survivors was increased when depression symptoms were present. The subjective perception of stress and the plasma cortisol levels were only marginally correlated in both groups.¦CONCLUSIONS: It is suggested that the exposure to a life-threatening experience in childhood/adolescence increases the endocrine response to stress, and that the presence of depressive symptoms is associated with an elevation of plasma cortisol levels. A better knowledge of these mechanisms is important given that the dysregulations of the stress responses may cause psychological vulnerability. Pediatr Blood Cancer 2012; 59: 138-143. © 2011 Wiley Periodicals, Inc.

Validation of the post-delivery perceived stress inventory

This article presents the post-delivery perceived stress inventory (PDPSI) and its psychometric properties. This inventory is unique in that it links the measurement of perceived stress to events experienced during and after delivery. A total of 235 French-speaking, primiparous mothers completed the PDPSI two days after their delivery. To evaluate the predictive validity of the PDPSI on anxiety and depression, participants also completed the EPDS and the STAI two days and six weeks postpartum. The exploratory analysis revealed a 16-item structure divided into five factors: F1: relationship with the child; F2: delivery; F3: fatigue after delivery; F4: breastfeeding; and F5: relationship with the caregivers. The PDPSI demonstrated good internal consistency. Moreover, confirmatory factor analysis produced excellent indices, indicating that the complexity of the PDPSI was taken into account and its fit to the sample. The discriminant analysis showed that the PDPSI was not sensitive to specific changes in the sample making the inventory generalizable to other populations. Predictive validity showed that the scale significantly predicted depression and anxiety in the early postpartum period as well as anxiety six weeks postpartum. Overall, the PDPSI showed excellent psychometric qualities, making it a useful tool for future research-evaluating interventions related to perceived stress during the postpartum period.

The influence of attachment on perceived stress and cortisol response to acute stress in women sexually abused in childhood or adolescence.

The long-term implications of sexual abuse in childhood or adolescence (CSA) have been relatively well documented regarding attachment (disorganized attachment in childhood, unresolved trauma in adulthood), stress reactions (altered patterns of stress reactivity under experimental conditions), and psychopathology. Attachment has been shown to mediate the implications of CSA, namely on psychopathology. The implication of attachment on stress responses of abused persons has not been documented. Twenty-seven 20-46 years old women who had experienced episodes of CSA, and 17 controls have been interviewed using the Adult Attachment Interview. Sixty-three percent of abused women presented an unresolved trauma (12% for the controls). Thirty-six women (14 controls and 22 abused) came again to the laboratory for a session involving an experimental stress challenge (TSST). Subjects provided repeated appreciations of perceived stress on visual analogue scales and saliva samples were collected to assay cortisol levels. Whereas abused women with unresolved trauma showed the highest levels of perceived stress, they simultaneously presented the most suppressed cortisol reactions (there were significant post hoc differences between "unresolved abused" and controls on the increase of perceived stress and on cortisol recovery after the acute stress). It is suggested that important stressful experiences (such as CSA), especially when they have not been psychologically assimilated, may cause a disconnection, during subsequent mildly stressful circumstances, between the perception of stress and natural defensive body reactions.

Energetics and mechanics of walking in patients with chronic low back pain and healthy matched controls.

PURPOSE: Walking in patients with chronic low back pain (cLBP) is characterized by motor control adaptations as a protective strategy against further injury or pain. The purpose of this study was to compare the preferred walking speed, the biomechanical and the energetic parameters of walking at different speeds between patients with cLBP and healthy men individually matched for age, body mass and height. METHODS: Energy cost of walking was assessed with a breath-by-breath gas analyser; mechanical and spatiotemporal parameters of walking were computed using two inertial sensors equipped with a triaxial accelerometer and gyroscope and compared in 13 men with cLBP and 13 control men (CTR) during treadmill walking at standard (0.83, 1.11, 1.38, 1.67 m s(-1)) and preferred (PWS) speeds. Low back pain intensity (visual analogue scale, cLBP only) and perceived exertion (Borg scale) were assessed at each walking speed. RESULTS: PWS was slower in cLBP [1.17 (SD = 0.13) m s(-1)] than in CTR group [1.33 (SD = 0.11) m s(-1); P = 0.002]. No significant difference was observed between groups in mechanical work (P ≥ 0.44), spatiotemporal parameters (P ≥ 0.16) and energy cost of walking (P ≥ 0.36). At the end of the treadmill protocol, perceived exertion was significantly higher in cLBP [11.7 (SD = 2.4)] than in CTR group [9.9 (SD = 1.1); P = 0.01]. Pain intensity did not significantly increase over time (P = 0.21). CONCLUSIONS: These results do not support the hypothesis of a less efficient walking pattern in patients with cLBP and imply that high walking speeds are well tolerated by patients with moderately disabling cLBP.

Validation of a brief form of the Perceived Neighborhood Social Cohesion questionnaire.

The aim of this study was the validation of a brief form of the Perceived Neighborhood Social Cohesion questionnaire using data from 5065 men from the "Cohort Study on Substance-Use Risk Factors." A 9-item scale covering three factors was proposed. Excellent indices of internal consistency were measured (α = .93). The confirmatory factor analyses resulted in acceptable fit indices supporting measurement invariance across French and German forms. Significant correlations were found between the brief form of the Perceived Neighborhood Social Cohesion questionnaire, and satisfaction and self-reported health, providing evidence of the concurrent validity of the scale. Perceived neighborhood social cohesion, and depression and suicide attempts were negatively associated, sustaining the protective effect of perceived social cohesion.

Validation of French and German versions of a Perceived Neighborhood Social Cohesion questionnaire among young Swiss males, and its relationship with substance use

This study main purpose was the validation of both French and German versions of a Perceived Neighborhood Social Cohesion Questionnaire. The sample group comprised 5065 Swiss men from the "Cohort Study on Substance Use Risk Factors." Multigroup Confirmatory factor analysis showed that a three-factor model fits the data well, which substantiates the generalizability of Perceived Neighborhood Social Cohesion Questionnaire factor structure, regardless of the language. The Perceived Neighborhood Social Cohesion Questionnaire demonstrated excellent homogeneity (α = 95) and split-half reliability (r = .96). The Perceived Neighborhood Social Cohesion Questionnaire was sensitive to community size and participants' financial situation, confirming that it also measures real social conditions. Finally, weak but frequent correlations between Perceived Neighborhood Social Cohesion Questionnaire and alcohol, cigarette, and cannabis dependence were measured.