Changes in swimming technique during time to exhaustion at freely chosen and controlled stroke rates     

Morgan Alberty  François Potdevin  Jeanne Dekerle  Patrick Pelayo  Philippe Gorce  Michel Sidney 《Journal of sports sciences》2013,31(11):1191-1200

Abstract

The aim of this study was to assess technical changes during constrained swimming in time-to-exhaustion tests. Ten swimmers of national standard performed a maximal 400-m front crawl and two sets of exhaustion tests at 95%, 100%, and 110% of mean 400-m speed. In the first set (free), swimmers had to maintain their speeds until exhaustion and mean stroke rate was recorded for each test. In the second set (controlled), the same speed and individual corresponding stroke rate were imposed. The durations of the exhaustion tests, relative durations of the stroke phases, and arm coordination were analysed. For each speed in the “controlled” set, the exhaustion tests were shorter. Moreover, variables were consistent, suggesting a stabilization of stroke technique. Under the free condition, stroke rate increased to compensate for the decrease in stroke length. At the same time, swimmers reduced the relative duration of their non-propulsive phases in favour of the propulsive phases. Thus, swimmers changed their arm coordination, which came close to an opposition mode. These two constraints enable swimmers both to maintain their stroking characteristics and develop compensatory mechanisms to maintain speed. Moreover, stroke rate can be seen as a useful tool for controlling arm technique during paced exercise.  相似文献   

Effectiveness of a heritage educational program for the acquisition of oral and written French and Tahitian in French Polynesia     

Isabelle Nocus  Philippe Guimard 《Teaching and Teacher Education》2012,28(1):21-31

The research examines the effects of a bilingual pedagogical program (French/Tahitian) on the acquisition of oral and written French as well as the Tahitian language itself in primary schools in French Polynesia. 125 children divided into an experimental group (partially schooled in Tahitian for 300 min per week) and a control group (schooled in French) were followed from the second year of kindergarten to Grade 1 and tested on Tahitian and French language competence. The results show that the program appears to have a positive impact on Tahitian proficiency, without any negative effect on learning of French (oral and reading).  相似文献   

L’apprentissage instrumenté de propriétés en géométrie : propédeutique à l’acquisition d’une compétence de démonstration     

Sylvia Coutat  Colette Laborde  Philippe R. Richard 《Educational Studies in Mathematics》2016,93(2):195-221

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‘White men can’t jump in a black basketball game?’ An exploratory investigation of implicit strategies of outgroup discrimination     

Rodolphe Perchot  Florent Mangin  Marie-Françoise Lacassagne  Philippe Castel 《Sport in Society》2017,20(11):1644-1666

Examining the ‘natural’ athlete myth and utilizing the recent literature on cultural/social factors in athleticism and basketball, this study through survey research examines the influence of stereotypes on the impression formation of basketball players. The primary research question is to determine from a group of students the attitudes of basketball players in terms of how they evaluate white and black players in basketball. The purpose is to identify participants’ perceptions and their appreciation as to whether or not black are superior to white basketball players. The theoretical framework employed is articulated around the theory of social categorization and racial stereotypes already observed in sports. In an initial qualitative phase, the results show that stereotypical representations exert an influence on the skills associated with basketball players depending on the colour of their skin, which is reflected in the use of adjectives specific to each of the categories of black and white. In a second quantitative phase, whereas a more favourable view of black basketball players might have been attributable to positive discrimination as per the anti-racist norm, the results show the activation of a bias towards favouring one’s own group. Once all of the initial adjectives have been expressed, the targets behave in the expected way in terms of the laws of social categorization i.e. they have a more positive view of the members of their own group (the Whites) than of the other group (the Blacks) as adjectives are cited for describing skills.  相似文献   

Assessment of the risk and biomechanical consequences of lateral epicondylalgia by estimating wrist and finger muscle capacities in tennis players     

Laurent Vigouroux  Benjamin Goislard de Monsabert  Chris Hayot  Philippe Androuet  Éric Berton 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(4):434-451

Previous studies suggested that a pronounced weakness of the extensor muscles relative to the flexor muscles could increase the risk of occurrence of lateral epicondylalgia. This study investigates this hypothesis by estimating the ratio of extensor to flexor muscle capacities among healthy non-players (n = 10), healthy tennis players (n = 20), symptomatic players (n = 6), and players who have recovered from lateral epicondylalgia (n = 6). Maximum net joint moments in flexion or extension were measured during seven tasks involving the voluntary contraction of wrist and fingers. Using these data, the muscle capacities of the main muscle groups of the hand (wrist flexors, wrist extensors, finger flexors, finger extensors, and intrinsic muscles) were estimated using a musculoskeletal model. These capacities were then used to compute the extensor/flexor capacity ratios about the wrist and the finger joints. Compared to healthy non-players, healthy players presented higher extensor muscle capacities and greater capacity ratios showing that playing tennis generates specific adaptations of muscle capacities. Interestingly, symptomatic players, similar to those of non-players, showed more imbalanced ratios than healthy players. These results confirm that the ratio of extensor/flexor muscle capacities seems to be associated with lateral epicondylalgia and can be further used to understand its incidence and consequences.  相似文献