Relationships among training stress,mood and dehydroepiandrosterone sulphate/cortisol ratio in female cyclists     

Mikaël Bouget  Mathieu Rouveix  Odile Michaux  Jean-Marc Pequignot 《Journal of sports sciences》2013,31(12):1297-1302

Abstract

In this study, we examined the effect of rapidly increased training volume and intensity on hormonal responses (salivary cortisol [C] and urinary dehydroepiandrosterone sulphate [DHEA-S]) and recovery-stress state perceived by 12 female cyclists. Over the 4-day experimental period, there was an average increase in training load of approximately 122% compared with that during the previous 12 days. Scores on subscales of the Recovery Stress Questionnaire for Athletes increased for the somatic component of stress (Fatigue, Emotional Stress and Social Stress; P < 0.05) and decreased the factor indicating recovery (General Well Being; P < 0.05) after the heavy training period. The training programme increased resting concentrations of salivary cortisol (P < 0.05) and decreased the DHEA-S/C ratio (P < 0.05). The increase in training load of cyclists was correlated with this hormonal ratio (r = ?0.48, P < 0.05). Changes in resting cortisol concentration as a result of heavy training stress were positively related to the change in Physical Complaints (r = 0.69, P < 0.01). Negative relationships were also found between changes in the DHEA-S/C ratio and changes in the somatic component of stress. The present results suggest that there is a dose–response relationship between increased training load, resting DHEA-S/C ratio and subjective assessment of stress and recovery, implying that this ratio could be used as an indicator of training status in female athletes.  相似文献   

Execution time,kinetics, and kinematics of the mae-geri kick: Comparison of national and international standard karate athletes     

Joël Pozo  Guillaume Bastien 《Journal of sports sciences》2013,31(14):1553-1561

Abstract

Little is known of the performance characteristics of the shotokan karate mae-geri kick. The aim of this study was to compare the execution time, the lower limb kinetics and kinematics, and their respective repeatability in the mae-geri kick of karate athletes of two different standards. Seventeen adult black belt karate competitors (9 national and 8 international athletes) performed six kicks with their dominant lower limb on a striking surface, combining maximum force impact and velocity. Execution time of movement and lower limb kinematics were recorded with a high-speed camera. Maximum force at impact and the forces exerted on the ground were measured using three force plates. The duration of the kick was significantly shorter for international than for national standard athletes. However, no significant difference in the maximum impact force of the kick was observed between the two groups. In addition, significant kinematic differences were observed between the groups, with two angles of motion and one velocity peak occurring sooner in the kick movement for the international athletes, specifically for the knee joint. International athletes also performed the kick with a significantly higher repeatability for duration and kinematics, specifically during the pre-loading phase that precedes the attack phase. We conclude that theduration of the kick and repeatability of lower limb kinematics could be useful in selecting top-level karate athletes and monitoring their training status.  相似文献   

The Validity of the Sit-and-Reach Test and the Modified Sit-and-Reach Test in Middle-Aged to Older Men and Women     

Koen A. P. M. Lemmink  Han C. G. Kemper  Mathieu H. G. Greef  Piet Rispens  Martin Stevens 《Research quarterly for exercise and sport》2013,84(3):331-336

Abstract

A growing concern for the establishment of a national system of education was clearly evident in France during the last decades of the eighteenth century. Physical education was afforded an important role in the educational projections of the period. Beginning with La Chalotais' Essai d'éducation nationale (1763) authors began to express more and more support for the inclusion of a comprehensive program of physical education. Gabriel Coyer's De l'éducation publique (1770), Louis Philipon de la Madelaine's Vues patriotiques sur l'education du peuple (1783) and De l'éducation des collèges (1784), and Jean Ver dier's Maison d'éducation physique et morale (1772) and Cours d'éducation à l'usage des eleves (1777) all contributed significantly to the concept that physical education must constitute an important and integral part of any comprehensive and viable plan for national education. Among the most important deliberations of the various French revolutionary assemblies between 1789 and 1795 were those dealing with education as a concern of the state. Legislators tried valiantly to establish a sound national plan for education. The educational reports and projects presented to the various revolutionary assemblies by Talleyrand, Condorcet, Lepelitier, Lakanal, Romme, and Daunou are usually considered by educational historians to be the most significant. Each of these specified that due attention must be devoted to physical education for children and youth. The proposals, the decrees and the debates which they precipitated did much to attract attention to the importance of the subject. It seems most likely that the period from 1763 to 1795 in France witnessed the establishment of a precedent in modem times for the concept of state concern and support for physical education.  相似文献   

Predicting Physical Activity Among Children: Investigating Interaction Effects in the Theory of Planned Behavior     

Mathieu Gourlan  Julie Boiché  Monica Takito  Bruno Fregeac  Florence Cousson-Gélie 《Research quarterly for exercise and sport》2013,84(4):490-497

ABSTRACT

Purpose: The theory of planned behavior (TPB) has been criticized for not including interactions between the variables assumed to predict behavior. This study sought to test how TPB variables interact to predict physical activity (PA) in children. Method: Four hundred thirty-eight children (M_age = 8.6 years, SD = 1.6 years) completed a TPB questionnaire and a PA questionnaire at Time 1. The PA measure was repeated 2 months later. Path analyses were performed to test the hypothesized model including interaction terms between TPB variables. Simple slopes analyses were also carried out to examine the statistically significant interaction terms. Results: Path analyses confirmed the classical hypotheses of TPB (R² for intentions = .39, R² for PA = .12) and also demonstrated only statistically significant Attitudes × Perceived Behavioral Control and Subjective Norms × Attitudes interactions (R² change for intentions = .01, p = .009). Simple slopes analyses revealed that the strength of the association between perceived behavioral control and intentions was only statistically significantly higher (t = 2.18, p = .05, d = 0.34, 95% CI [0.03, 0.65]) when attitudes were high compared with when attitudes were low. The link between attitudes and intentions was only statistically significant at a low level of subjective norms but not at a high level. Conclusion: The integration of interaction effects between TPB variables did not increase for the variance of PA explained by the model. More research appears to be necessary to explore how the TPB could be augmented to better predict PA in children.  相似文献   

Upper secondary and first-year university students’ explanations of animal behaviour: to what extent are Tinbergen’s four questions about causation,ontogeny, function and evolution,represented?     

Rianne Pinxten  Mathieu Desclée  Marcel Eens 《International Journal of Science Education》2016,38(14):2303-2325

In 1963, the Nobel Prize-winning ethologist Niko Tinbergen proposed a framework for the scientific study of animal behaviour by outlining four questions that should be answered to have a complete understanding: causation, ontogeny, function and evolution. At present, Tinbergen’s framework is still considered the best way to guide animal behavioural research. Given the importance in science instruction of demonstrating how scientists work and ask questions, we investigated to what extent Tinbergen’s questions are addressed in biology textbooks in secondary education in Flanders, Belgium, and represented in upper-secondary and first-year university students’ explanations of behaviour in general and of specific animal behaviours. Our results revealed that teaching of animal behaviour mainly addresses ontogeny and causation, and that Tinbergen’s framework is not explicitly referred to. Students typically addressed only one or two questions, with the majority addressing causation or both causation and ontogeny when explaining behaviour in general, but function or causation and function when explaining specific animal behaviours. This high prevalence of function may be due to teleological thinking. Evolution was completely neglected, even in university students who had recently completed an evolution course. Our results revealed that transfer of the concepts of ontogeny and evolution was (almost) absent. We argue why Tinbergen’s framework should be an integral part of any biology curriculum.  相似文献   

Acidic open-cage solution containing basic cage-confined nanospaces for multipurpose catalysis     

Kang Li  Kai Wu  Yan-Zhong Fan  Jing Guo  Yu-Lin Lu  Yuan-Fan Wang  Guillaume Maurin  Cheng-Yong Su 《国家科学评论(英文版)》2022,9(5)

The nanoscale chemical spaces inherent in porous organic/coordination cages or solid/liquid materials have been continuously explored for their nanoconfinement effect on selective adsorption and reaction of small gas or organic molecules. Herein, we aim to rationalize the unconventional chemical reactivities motivated by the cage-confined nanospaces in aqueous solutions, where the robust yet permeable nanospaces defined by the open cages facilitate dynamic guest exchange and unusual chemical reactions. The high positive charges on [(Pd/Pt)₆(RuL₃)₈]²⁸⁺ nanocages drive imidazole–proton equilibrium to display a significantly perturbed pK_a shift, creating cage-defined nanospaces in solution with distinct intrinsic basicity and extrinsic acidity. The supramolecular cage effect plays pivotal roles in elaborating robust solution nanospaces, controlling ingress-and-egress molecular processes through open-cage portals and endowing nanocages with transition-state stabilization, amphoteric reactivities and the phase transfer of insoluble molecules, thus promoting chemical transformations in unconventional ways. Consequently, a wide range of application of cage-confined catalysis with anomalous reactivities may be expected based on this kind of open-cage solution medium, which combines cage nanocavity, solution heterogeneity and liquid-phase fluidity to benefit various potential mass transfer and molecular process options.  相似文献   

The Influence of Coaching on Employee Performance: Results From Two International Quantitative Studies     

Claudio Pousa  Anne Mathieu 《Performance Improvement Quarterly》2014,27(3):75-92

Coaching has been identified as a key managerial behavior that organizations must promote to develop employees and achieve higher levels of performance. Despite this agreement and an increasing interest in coaching, there is still a paucity of studies exploring the impact of coaching on individual performance. This article presents an empirical investigation from two international field studies, one using business‐to‐business salespersons working in Latin America and the other one using business‐to‐consumer frontline employees from a service organization in Canada. Building on leader‐member exchange theory, we propose that coaching increases individual performance beyond the potential impact of sales experience and tenure. We find that coaching can explain between 2.9% and 6.2% of the variance in performance when controlling for tenure and experience. This article makes several scientific and managerial contributions, and also opens new avenues for research.  相似文献