Asymmetry in elite rowers: effect of ergometer design and stroke rate     

Vincent Fohanno  Antoine Nordez  Richard Smith 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):310-322

Between limb movement asymmetries and foot force production asymmetries are thought to be detrimental for both rower's performance and risk of injury, particularly when rowing frequently on ergometers. Several ergometers with different designs can be used by rowers as part of their indoor training. Hence, this study aimed to compare asymmetries in lower limb joint kinematics and foot force production with respect to ergometer design and rowing intensity. A new symmetry index was proposed to assess these asymmetries in elite rowers during a test on three ergometers. Additionally, the asymmetry in lower limb length was assessed to investigate its relationship with kinematic and kinetic asymmetries. Parameters describing medium (5–10%) or high (>10%) asymmetries were compared between rowing ergometers and intensities. Results indicated medium asymmetries for the ankle joint angle and hip–knee joint accelerations and high asymmetries for the resultant force and the ankle joint acceleration associated with a low inter-stroke variability. Kinetic asymmetry was neither correlated to kinematic asymmetry nor with lower limb length asymmetry. The use of a mobile ergometer led to higher joint acceleration asymmetries. Further studies are necessary to investigate the relation between these findings and muscular adaptations that may increase the risk of lower-back injury.  相似文献   

A "dry and wet hybrid" lithography technique for multilevel replication templates: Applications to microfluidic neuron culture and two-phase global mixing     

Paul D  Saias L  Pedinotti JC  Chabert M  Magnifico S  Pallandre A  De Lambert B  Houdayer C  Brugg B  Peyrin JM  Viovy JL 《Biomicrofluidics》2011,5(2):24102

A broad range of microfluidic applications, ranging from cell culture to protein crystallization, requires multilevel devices with different heights and feature sizes (from micrometers to millimeters). While state-of-the-art direct-writing techniques have been developed for creating complex three-dimensional shapes, replication molding from a multilevel template is still the preferred method for fast prototyping of microfluidic devices in the laboratory. Here, we report on a "dry and wet hybrid" technique to fabricate multilevel replication molds by combining SU-8 lithography with a dry film resist (Ordyl). We show that the two lithography protocols are chemically compatible with each other. Finally, we demonstrate the hybrid technique in two different microfluidic applications: (1) a neuron culture device with compartmentalization of different elements of a neuron and (2) a two-phase (gas-liquid) global micromixer for fast mixing of a small amount of a viscous liquid into a larger volume of a less viscous liquid.  相似文献   

A winner’s curse in the bidding process for broadcasting rights in football? The cases of the French and UK markets     

Antoine Feuillet  Nicolas Scelles  Christophe Durand 《Sport in Society》2019,22(7):1198-1224

The winner’s curse is a well-known phenomenon in the auction theory. The main aim of this article is to verify its existence in football broadcasting rights. The underlying objective is to assess whether some indices of this situation are verified and can cause a winner’s curse. The methodology is based on the application of Andreff (2014 Andreff, Wladimir. 2014. “The Winner’s Curse in Sports Economics.” Contemporary Research in Sports Economics 14: 177–205. [Google Scholar])’s six indices and a seventh index (disappointment) to the domestic markets for broadcasting rights of the French and English football leagues. These two markets have seen an increase in the number of packages offered to broadcasters, with the possibility of several ‘winners’. The article shows that the winner of the major packages in the auction is not cursed. The curse is more likely to happen for the second mover. As such, the article suggests a practical recommendation for broadcasters interested in football rights: win the best package or keep away.  相似文献   

Adipose tissue lipolytic inhibition enhances the glucoregulatory properties of exercise in type 2 diabetes patients     

Dominique Hansen  Jan-Willem van Dijk  Antoine Zorenc  Lennert Minten  Kevin Smeets 《European Journal of Sport Science》2018,18(9):1245-1254

Aims: Exercise combined with adipose tissue lipolytic inhibition augments intramuscular lipid and glycogen use in type 2 diabetes patients. The present study investigates the impact of adipose tissue lipolytic inhibition during exercise on subsequent postprandial glycemic control in type 2 diabetes patients.

Methods: Fourteen male type 2 diabetes patients (age 65?±?2 years, HbA_1c 6.7?±?0.1% (50?±?2?mmol/mol)) participated in a double-blind placebo-controlled randomized cross-over study in which subjects performed endurance-type exercise after being administered 250?mg of a nicotinic acid analogue (acipimox; ACP) or a placebo (PLA). A control experiment was included in which no exercise was performed (CON).

Results: Sixty minutes of endurance-type exercise (at 45% W_peak) did not significantly lower circulating plasma glucose and insulin excursions in PLA when compared with CON (P?=?.300). Acipimox administration strongly reduced circulating plasma FFA concentrations during exercise (P?i.e. postprandial) in ACP when compared with either CON (P?=?.041 and P?=?.002, respectively) or PLA (P?=?.009 and P?=?.001, respectively).

Conclusions: Collectively, exercise with adipose tissue lipolytic inhibition reduces postprandial blood glucose and insulin excursions and, as such, further improves glycemic control in male type 2 diabetes patients.  相似文献   

Mental fatigue alters the speed and the accuracy of the ball in table tennis     

Yann Le Mansec  Benjamin Pageaux  Antoine Nordez  Sylvain Dorel 《Journal of sports sciences》2018,36(23):2751-2759

ABSTRACT

This study aimed at evaluating the effects of mental and muscle fatigue on table tennis performance. Mental fatigue (MF) was induced by completion of 90 minutes of the AX-CPT; muscle fatigue was induced by completion of an eccentric exercise performed with the elbow flexors (biceps fatigue, BF) or the knee extensors (quadriceps fatigue, QF). The control condition consisted of watching a movie. Stroke parameters (speed and accuracy of the ball), as well as feelings of fatigue and force production capacity of the elbow flexors (BF, MF and control conditions) and knee extensors (QF condition), were assessed pre and post fatigue protocols. Feelings of fatigue increased post fatigue protocols. Force production capacity decreased only in the BF and QF conditions. BF and MF induced a decrease in accuracy. This decrease in accuracy was associated with an increased ball speed in the BF condition, and a decreased ball speed in the MF condition. QF had a negligible effect on stroke performance. Our results suggest that both mental fatigue, and muscle fatigue, significantly impair table tennis performance and therefore coaches should take into account both the physical and mental state of table tennis players to optimize performance.  相似文献   

The effects of desegregation: Is the cup half empty or half full?     

Antoine M. Garibaldi 《The Urban Review》1981,13(4):265-270

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Comparing Collective and Personal Professional Theories of Experienced Practitioners     

Antoine C. M. van den Bogaart  Marco Mazereeuw  Hans G. K. Hummel  Paul A. Kirschner 《Scandinavian Journal of Educational Research》2019,63(3):363-377

A characteristic of being a professional is the internalisation of the collective professional theory (CPT)—the shared insights of professionals. Problems arise when different opinions stemming from professionals’ personal professional theories (PPTs) obscure a CPT’s content. This study argues that cooperating professionals’ CPTs form a so-called field and can be represented by concept maps. The relations between PPTs, CPTs, and fields are examined for the fields of accountancy and teaching. The results indicate that CPTs are more complex than PPTs, and that the teachers’ field is more diverse than the accountants’ field. These insights are important because socialisation in a field may be fostered if one is aware of CPTs and the surrounding field in relation to one’s PPT.  相似文献   

The association between teacher participation in NSF institutes and student achievement     

Victor L. Willson  Antoine M. Garibaldi 《科学教学研究杂志》1976,13(5):431-439

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“My Questionnaire is Too Long!” The assessments of motivational-affective constructs with three-item and single-item measures     

Katarzyna Gogol  Martin Brunner  Thomas Goetz  Romain Martin  Sonja Ugen  Ulrich Keller  Antoine Fischbach  Franzis Preckel 《Contemporary educational psychology》2014

Because testing time in educational research is typically scarce, the use of long scales to assess motivational-affective constructs can be problematic. The goal of the present study was to scrutinize the psychometric properties of short scales (with three items) and single-item measures for two core motivational-affective constructs (i.e., academic anxiety and academic self-concept) by conducting systematic comparisons with corresponding long scales across school subjects and within different subject domains (i.e., mathematics, German, French). Statistical analyses were based on representative data from 3879 ninth-grade students. All short forms possessed satisfactory levels of reliability (range: .75–.89) and substantial correlations with the long scales (range: .88–.97); correlational patterns with educational student characteristics (e.g., achievement, school satisfaction, gender, academic track, and socioeconomic status) were comparable to those obtained with the corresponding long scales (all average differences in correlations below .07). The correlational patterns between all single-item measures and the external criteria were similar to those obtained with the corresponding long scales (all average differences in correlations below .08), yet the single-item measures demonstrated low to modest score reliabilities (estimated with the model-based omega coefficient; range: .22–.72) and correlations with full scales (range: .50–.88). When long scales are not applicable, short forms and perhaps even single-item measures may represent psychometrically sound alternatives for assessing academic anxiety and academic self-concept for educational research purposes.  相似文献   

Droplet microfluidics for kinetic studies of viral fusion     

Samaneh Mashaghi  Antoine M. van Oijen 《Biomicrofluidics》2016,10(2)

Viral infections remain a major threat to public health. The speed with which viruses are evolving drug-resistant mutations necessitates the further development of antiviral therapies with a large emphasis on drug discovery. To facilitate these efforts, there is a need for robust, high-throughput assays that allow the screening of large libraries of compounds, while enabling access to detailed kinetic data on their antiviral activity. We report here the development of a droplet-based microfluidic platform to probe viral fusion, an early critical step in infection by membrane-enveloped viruses such as HIV, Hepatitis C, and influenza. Using influenza A, we demonstrate the measurement of the kinetics of fusion of virions with target liposomes with sub-second temporal resolution. In analogy with acidification of the endosome that triggers fusion in a cellular context, we acidify the content of aqueous droplets containing virions and liposomes in situ by introducing acid from the dispersed phase and visualize the kinetics of fusion by using fluorescent probes.  相似文献