Effect of swimming velocity on arm coordination in the front crawl: a dynamic analysis     

L Seifert  D Chollet  BG Bardy 《Journal of sports sciences》2013,31(7):651-660

We examined the preferred mode of arm coordination in 14 elite male front-crawl swimmers. Each swimmer performed eight successive swim trials in which target velocity increased from the swimmer's usual 3000-m velocity to his maximal velocity. Actual swim velocity, stroke rate, stroke length and the different arm stroke phases were then calculated from video analysis. Arm coordination was quantified by an index of coordination based on the lag time between the propulsive phases of each arm. The index expressed the three coordination modes in the front crawl: opposition, catch-up and superposition. First, in line with the dynamic approach to movement coordination, the index of coordination could be considered as an order parameter that qualitatively captured arm coordination. Second, two coordination modes were observed: a catch-up pattern (index of coordination?=??8.43%) consisting of a lag time between the propulsive phases of each arm, and a relative opposition pattern (index of coordination?=?0.89%) in which the propulsive phase of one arm ended when the propulsive phase of the other arm began. An abrupt change in the coordination pattern occurred at the critical velocity of 1.8?m?·?s^?1, which corresponded to the 100-m pace: the swimmers switched from catch-up to relative opposition. This change in coordination resulted in a reorganization of the arm phases: the duration of the entry and catch phase decreased, while the duration of the pull and push phases increased in relation to the whole stroke. Third, these changes were coupled to increased stroke rate and decreased stroke length, indicating that stroke rate, stroke length, the stroke rate/stroke length ratio, as well as velocity, could be considered as control parameters. The control parameters can be manipulated to facilitate the emergence of specific coordination modes, which is highly relevant to training and learning. By adjusting the control and order parameters within the context of a specific race distance, both coach and swimmer will be able to detect the best adapted pattern for a given race pace and follow how arm coordination changes over the course of training.  相似文献   

A new index of flat breaststroke propulsion: A comparison of elite men and women     

L Seifert  D Chollet 《Journal of sports sciences》2013,31(3):309-320

This study examined arm and leg coordination and propulsion during the flat breaststroke in nine elite male and eight elite female swimmers over three race paces (200?m, 100?m and 50?m). Coordination was expressed using four temporal gaps (T1, T2, T3, T4), which described the continuity between the propulsive phases of the limbs, as recorded on a video device (50 Hz). Glide duration was denoted T1, the time between the beginning of arm and leg recovery was denoted T2, the time between the end of arm and the leg recovery was denoted T3, and the time between 90° of flexion during arm recovery and 90° during leg recovery was denoted T4. Using these temporal gaps, four stroke phases (propulsion, glide, recovery and leg insweep) could be followed over a complete arm and leg stroke. The total duration of arm and leg propulsion was assessed by a new index of flat breaststroke propulsion (IFBP). Velocity, stroke rate and stroke length were also calculated for each pace. The elite swimmers showed short T2, T3 and T4; moreover, T1 decreased when the pace increased. Expertise in the flat breaststroke was thus characterized by synchronized arm and leg recoveries and increased continuity in the arm and leg propulsions with increasing velocity. Differences between the sexes in the spatio-temporal parameters were possibly due to anthropometric differences (the men were heavier, older and taller than the women) and different motor organization linked to arm and leg coordination (shorter T3, body glide and body recovery, and greater body propulsion and higher IFBP in the men). The men's propulsive actions showed greater continuity, particularly in the sprint. The best men adopted a superposition coordination and thus had the ability to overcome very great active drag. Temporal gap measurement and the IFBP are practical indicators of arm and leg coordination and propulsion that can be exploited by coaches and swimmers to increase the continuity between propulsive actions during the flat breaststroke.  相似文献   

Analysis of elite swimmers' activity during an instrumented protocol     

Adé David  Germain Poizat  Nathalie Gal-Petitfaux  Huub Toussaint  M. Ludovic Seifert 《Journal of sports sciences》2013,31(10):1043-1050

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Analysing expertise through data mining: an example based on treading water     

Christophe Schnitzler  Chris Button  Ludovic Seifert  James Croft 《Journal of sports sciences》2013,31(12):1186-1195

Abstract

A classification system of treading water based on a conceptual typology was first established and then verified empirically. The typology was established on two concepts: the nature of the forces created within the water and the type of inter-limb coordination used. Thirty-eight participants were videotaped while treading water. Multivariate statistics were used to understand how the different behavioural types related to expertise. Three distinct groups of coordination patterns were adopted during treading water. A support vector machine procedure was used as a confirmatory procedure. The data mining process provides a methodological framework to analyse expertise in sports activities, and in this context suggests that a taxonomy can be established among the numerous coordination solutions that allow humans to create stabilising forces in the water.  相似文献   

AN INVESTIGATION OF CRITICAL MASS: The Role of Latino Representation in the Success of Urban Community College Students   总被引：3，自引：0，他引：3  

Linda Serra Hagedorn  Winny Chi  Rita M. Cepeda  Melissa McLain 《Research in higher education》2007,48(1):73-91

The community college has historically functioned as a primary access point to postsecondary education for Latino students. This study, an investigation conducted through an analysis of the Transfer and Retention of Urban Community College Students (TRUCCS) project, focuses on Latino students enrolled in urban “minority-majority” community colleges, where Latino students have a high representation. The specific interest of this research is the role and effect of the level of representation of Latino community college students on their academic outcomes. The relationship between the level of representation of Latinos, and the levels of academic success are analyzed in concert with other variables, such as, the level of representation of Latino faculty on campus, student age, attitude, academic integration, English ability and aspiration. Findings indicate a relationship between academic success of Latino community college students and the proportion of Latino students and faculty on campus. The findings thus suggest that a critical mass of Latinos may be a positive influence encouraging “minority” students to higher academic performance.  相似文献   

Going Deep into Mechanisms for Moral Reasoning Growth: How Deep Learning Approaches Affect Moral Reasoning Development for First-year Students     

Matthew J. Mayhew  Tricia A. Seifert  Ernest T. Pascarella  Thomas F. Nelson Laird  Charles F. Blaich 《Research in higher education》2012,53(1):26-46

The purpose of this paper was to determine the effects of deep approaches to learning on the moral reasoning development of 1,457 first-year students across 19 institutions. Results showed a modest positive relationship between our measures of deep approaches to learning and moral reasoning at the end of the first year of college even after controlling for precollege moral reasoning. After accounting for a host of demographic and relevant student characteristics and for the natural clustering of students, we found that the integrative learning subscale, which captures students’ participation in activities designed to integrate information from varied sources and diverse perspectives, positively affected moral reasoning among first-year students. Implications for researchers and practitioners are discussed.  相似文献   

Who knows what school leavers and graduates are doing? Comparing information systems within Europe     

Rita Hordosy 《比较教育学》2014,50(4):448-473

Many current national and institutional education policies address the issue of raising participation amongst young people and enhancing employability after leaving school or university. What sort of information are these policies built on? This paper compares national information systems from the last three decades across Europe that gather information on school leavers' and graduates' pathways after compulsory education. Using documentary data collected systematically the paper describes the main focus, the research design and the sampling frame of the school leavers' and graduates' information systems (SLGIS) arriving at several different typologies. This paper gives an overall picture of what sort of research is conducted within the area of school leaving and graduation and points out the advantages and disadvantages of the different approaches. Beyond these, the paper gives an indication of how the school leavers’ and graduates’ data are used within the different European contexts and points towards the next steps of this meta-research: case-studies on how the school leavers' and graduates' data are applied at the national and the institutional level.  相似文献   

How Moroccan mothers and fathers view child development and their role in their children's education     

Gail L. Zellman  Michal Perlman  Rita Karam 《International Journal of Early Years Education》2014,22(2):197-209

Despite the documented importance of parental engagement in early learning, little is known about how parents in the Middle East and North Africa understand child development. To inform the literature, a small-scale study involving four focus groups was conducted with parents of children aged six years and under living in Casablanca. The purpose of this study was to explore parents' understanding of and support for their children's early development. Results reveal that parents see a vital role for themselves in their children's upbringing as supporters and nurturers, but little role as teachers. Across different education and income levels, parents in this small-scale qualitative study believe that children's experiences in their first years of life do not affect their longer-term intellectual development or school success and see little value in early intellectual stimulation or formal preschool education. Our results suggest that parents need to understand their role as their child's first educators. Also, it is essential that parents are taught how to promote their children's early cognitive development without undermining their nurturing roles.  相似文献   

The Bologna Process Offers New Research Opportunities for Academic Business Librarians Worldwide     

Harold Gee  Rita Ormsby 《Journal of Business & Finance Librarianship》2013,18(1):67-84

European education ministers and officials signed a Bologna Declaration with a goal to reform, strengthen, and standardize higher education programs and degree structures by 2010. Graduates will become more mobile and marketable to employers throughout Europe. These programs shall also attract students worldwide. Higher education programs on other continents have taken notice and are in the process of initiating similar goals and outcomes. All of these events are creating new research opportunities for academic business librarians in all aspects of library support and services including collection development, reference, and instruction.  相似文献   

Teaching thinking: the case for principles     

Rita R. Jordan  Stuart D. Powell 《欧洲特需教育杂志》2013,28(2):112-123

Abstract

This paper reviews the situation with regard to the teaching of thinking skills as part of the taught curriculum. The case is made for direct teaching of cognitive skills both to meet the particular learning difficulties of children with special educational needs and also to enhance the learning and thinking of all children. The dangers of ‘recipe’ approaches to teaching this aspect of the curriculum are discussed and a ‘principles’ approach is advocated. Some principles are then described which may be used to underpin the designing of problem‐solving activities, through which thinking skills can be taught across the curriculum.  相似文献