No abstract

The hypothesis that the S allele of the 5-HTTLPR serotonin transporter promoter region is associated with increased risk of depression, but only in individuals exposed to stressful situations, has generated much interest, research, and controversy since first proposed in 2003. Multiple meta-analyses combining results from heterogeneous analyses have not settled the issue. To determine the magnitude of the interaction and the conditions under which it might be observed, we performed new analyses on 31 datasets containing 38 802 European-ancestry subjects genotyped for 5-HTTLPR and assessed for depression and childhood maltreatment or other stressful life events, and meta-analyzed the results. Analyses targeted two stressors (narrow, broad) and two depression outcomes (current, lifetime). All groups that published on this topic prior to the initiation of our study and met the assessment and sample size criteria were invited to participate. Additional groups, identified by consortium members or self-identified in response to our protocol (published prior to the start of analysis1) with qualifying unpublished data were also invited to participate. A uniform data analysis script implementing the protocol was executed by each of the consortium members. Our findings do not support the interaction hypothesis. We found no subgroups or variable definitions for which an interaction between stress and 5-HTTLPR genotype was statistically significant. In contrast, our findings for the main effects of life stressors (strong risk factor) and 5-HTTLPR genotype (no impact on risk) are strikingly consistent across our contributing studies, the original study reporting the interaction, and subsequent meta-analyses. Our conclusion is that if an interaction exists in which the S allele of 5-HTTLPR increases risk of depression only in stressed individuals, then it is not broadly generalizable, but must be of modest effect size and only observable in limited situations.

Brink, MS, Nederhof, E, Visscher, C, Schmikli, SL, and Lemmink, KAPM. Monitoring load, recovery, and performance in young elite soccer players. J Strength Cond Res 24(3): 597-603, 2010-The purpose of this study was to investigate the relation between training load, recovery, and monthly field test performance in young elite soccer players to develop training guidelines to enhance performance. In a prospective, nonexperimental cohort design, 18 young elite soccer players registered training and match duration for a full competitive season by means of daily training logs. Furthermore, session rating of perceived exertion (RPE) and total quality of recovery (TQR) scores were recorded. Weekly duration (TL d ), load (duration 3 session RPE = TL rpe ), and TQR scores were calculated for 1 and 2 weeks before a monthly submaximal interval shuttle run tests to determine interval endurance capacity. Participants spent on average 394.4 6 134.9 minutes per week on training and game play with an average session RPE of 14.4 6 1.2 (somewhat hard) and TQR of 14.7 6 1.3 (good recovery). Random intercept models showed that every extra hour training or game play resulted in enhanced field test performance (p , 0.05). Session RPE and TQR scores did not contribute to the prediction of performance. The duration of training and game play in the week before field test performance is most strongly related to interval endurance capacity. Therefore, coaches should focus on training duration to improve interval endurance capacity in elite soccer players. To evaluate the group and individual training response, field tests should be frequently executed and be incorporated in the training program.

Positive affect has been implicated in the phenomenological experience of various psychiatric disorders, vulnerability to develop psychopathology and overall socio-emotional functioning. However, developmental influences that may contribute to positive affect have been understudied. Here, we studied youths' 5-HTTLPR genotype and rearing environment (degree of positive and supportive parenting) to investigate the differential susceptibility hypothesis (DSH) that youth carrying short alleles of 5-HTTLPR would be more influenced and responsive to supportive and unsupportive parenting, and would exhibit higher and lower positive affect, respectively. Three independent studies tested this gene–environment interaction (GxE) in children and adolescents (age range 9–15 years; total N=1874). In study 1 (N=307; 54% girls), positive/supportive parenting was assessed via parent report, in study 2 (N=197; 58% girls) via coded observations of parent–child interactions in the laboratory and in study 3 (N=1370; 53% girls) via self report. Results from all the three studies showed that youth homozygous for the functional short allele of 5-HTTLPR were more responsive to parenting as environmental context in a ‘for better and worse' manner. Specifically, the genetically susceptible youth (that is, S'S' group) who experienced unsupportive, non-positive parenting exhibited low levels of positive affect, whereas higher levels of positive affect were reported by genetically susceptible youth under supportive and positive parenting conditions. These GxE findings are consistent with the DSH and may inform etiological models and interventions in developmental psychopathology focused on positive emotion, parenting and genetic susceptibility.

Objective protocol can be used to make an objective, immediately available distinction between non-functional over reaching (NFO) and overtraining syndrome (OTS) was studied. Design with the suspicion of NFO or OTS were included in the study. Recovery of the athletes was monitored by a sports physician to retrospectively distinguish NFO from OTS. Setting Sports medicine laboratory Participants by 10 underperforming athletes. NFO was retrospectively diagnosed in five athletes, and OTS was diagnosed in five athletes. Interventions was used to measure physical performance and stressinduced hormonal reactions. Main outcome measurements rate and blood lactate concentration were measured at the end of both exercise tests. Venous concentrations cortisol, adrenocorticotrophic hormone (ACTH), prolactin and growth hormone were measured both before and after both exercise tests. Results in OTS compared with NFO, while resting concentrations of cortisol, ACTH and prolactin concentrations were higher. However, sensitivity of these measures was low. The ACTH and prolactin reactions to the second exercise bout were much higher in NFO athletes compared with OTS and showed the highest sensitivity for making the distinction. Conclusions NFO might be distinguished from OTS based on ACTH and prolactin reactions to a two-bout exercise protocol. This protocol could be a useful tool for diagnosing NFO and OTS; however, more data should be collected before this test can be used as the gold standard.The goal in training competitive athletes is to provide training loads that are effective in improving performance. At some stages during the training process, athletes may experience an unexplainable decrease in performance. This might happen when prolonged excessive training takes place concurrent with other stressors and insufficient recovery. This unexplainable performance decrements can result in chronic maladaptations that can lead to the overtraining syndrome (OTS). A keyword in the recognition of OTS might be ''prolonged maladaptation'' not only of the athletic performance but also of several biological, neurochemical and hormonal regulation mechanisms. When athletes deliberately use a short-term period (eg, training camp) to increase training load, they can experience short-term performance decrement, without severe psychological or lasting other negative symptoms.1 2 This functional over reaching (FO) will eventually lead to an improvement in performance after recovery. However, when athletes do not sufficiently respect the balance between training and recovery, non-functional over-reaching (NFO) can occur.1 2 At this stage, the first signs and symptoms of prolonged maladaptation such as performance decrements, psychological disturbance (decreased vigour, increased fatigue) and hormonal disturbances are present, and the athlete will need weeks or months to recover. The distinction between NFO and OTS is very difficult and will depend on the clinical outcome and exclusion diagnosis.The recent ''consensus statement'' of the ...

The adaptive calibration model (ACM) is a theory of developmental programing focusing on calibration of stress response systems and associated life history strategies to local environmental conditions. In this article, we tested some key predictions of the ACM in a longitudinal study of Dutch adolescent males (11-16 years old; N = 351). Measures of sympathetic, parasympathetic, and adrenocortical activation, reactivity to, and recovery from social-evaluative stress validated the four-pattern taxonomy of the ACM via latent profile analysis, though with some deviations from expected patterns. The physiological profiles generally showed predicted associations with antecedent measures of familial and ecological conditions and life stress; as expected, high- and low-responsivity patterns were found under both low-stress and high-stress family conditions. The four patterns were also differentially associated with aggressive/rule-breaking behavior and withdrawn/depressed behavior. This study provides measured support for key predictions of the ACM and highlights important empirical issues and methodological challenges for future research.

This project investigates how stressful events are related to deviations from normative temperament development during adolescence. Temperament traits were assessed at ages 11 and 16 years. Life-event data was captured using an interview (total n = 1197). Normative changes were found in all traits. A linear trend was found between the experience of stressful events and temperament development. Adolescents exposed to stressful events showed smaller decreases in fear and shyness, stronger decreases in effortful control and affiliation and smaller increases in high intensity pleasure. Exposure to stressful events was related to increases in frustration instead of decreases. Our results show that whereas normative development is mostly in the direction of maturation, adolescents who experienced stressful events showed less maturation of their temperament.

The current diagnosis of overreaching and overtraining is based on exclusion. In the present paper, four possible confirmative tools have been examined in three female speed skaters between 16 and 19 years old. A nonfunctional overreached (NFO) athlete, an athlete who was recovering from NFO and a healthy athlete were examined. The NFO athlete showed high stress and low regeneration levels at the Recovery Stress Questionnaire for Athletes. The recovering athlete showed a more favorable profile, although she still showed higher stress and lower recovery than the control athlete. On the Profile of Mood States, the NFO athlete showed an unfavorable profile. The control athlete showed the typical iceberg profile. The recovering athlete showed a profile similar to sedentary individuals. Results on a reaction time task showed decreased performance under pressure for the NFO but not for the control and the recovering athlete. Hormonal reactions to two maximal exercise bouts also differed between the three subjects with an overreaction after the second exercise bout of the NFO athlete as the most remarkable finding. The Recovery Stress Questionnaire for Athletes, reaction times and hormonal reactions to exercise showed to be possible tools that can be used in the diagnostic procedure.