Key somatic variables associated with,and differences between the 4 swimming strokes     

Alan M. Nevill  Yassine Negra  Tony D. Myers  Senda Sammoud  Helmi Chaabene 《Journal of sports sciences》2020,38(7):787-794

ABSTRACT

This study identified key somatic and demographic characteristics that benefit all swimmers and, at the same time, identified further characteristics that benefit only specific swimming strokes. Three hundred sixty-three competitive-level swimmers (male [n = 202]; female [n = 161]) participated in the study. We adopted a multiplicative, allometric regression model to identify the key characteristics associated with 100 m swimming speeds (controlling for age). The model was refined using backward elimination. Characteristics that benefited some but not all strokes were identified by introducing stroke-by-predictor variable interactions. The regression analysis revealed 7 “common” characteristics that benefited all swimmers suggesting that all swimmers benefit from having less body fat, broad shoulders and hips, a greater arm span (but shorter lower arms) and greater forearm girths with smaller relaxed arm girths. The 4 stroke-specific characteristics reveal that backstroke swimmers benefit from longer backs, a finding that can be likened to boats with longer hulls also travel faster through the water. Other stroke-by-predictor variable interactions (taken together) identified that butterfly swimmers are characterized by greater muscularity in the lower legs. These results highlight the importance of considering somatic and demographic characteristics of young swimmers for talent identification purposes (i.e., to ensure that swimmers realize their most appropriate strokes).  相似文献   

改革开放40年高等体育教育资源优化配置的社会学审视     

张孔军  钱娅艳 《北京体育大学学报》2019,42(2):103-114

摘要：我国高等体育教育资源优化配置研究引入社会学视角理论与方法，理论与实践均取得专家的认同。运用文献资料法、专家访谈法和实地考察法等方法发现，在计划经济体制下我国高等体育教育资源配置主体单一性、手段行政化和政治倾向性强，凸显出高等体育教育资源配置缺乏激励机制和市场竞争机制的问题，造成高等体育教育资源配置成本最大化和社会效应的最小化问题较多。自改革开放以来,随着我国市场经济体制的建立为高等体育教育资源优化配置提供了难得的发展机遇，我国高等体育教育资源配置取得了明显成效，但仍然存在高等体育教育资源配置机制滞后、体制机制改革创新步伐缓慢、高等体育教育资源配置不合理以及民办普通高校体育教育资源配置严重不足等问题。据此，从社会学研究的视角，提出了构建多主体推动高等体育教育资源优化配置创新的发展模式、多元化高等体育教育资源优化配置资金投入的保障体系、高等体育教育资源优化配置均衡发展的运行机制和大学城体育教育资源“共建共享”的创新发展模式的新时代我国高等体育教育资源优化配置的发展策略，旨在服务新时代全民健身与全民健康深度融合发展，“推动构建人类命运共同体”发展目标的实现。  相似文献   

Online visibility of software-related web sites: The case of biomedical text mining tools     

Gael Pérez-Rodríguez  Martín Pérez-Pérez  Florentino Fdez-Riverola  Anália Lourenço 《Information processing & management》2019,56(3):565-583

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The biomechanical characteristics of high-performance endurance running     

Stephen J. Preece  Christopher Bramah  Duncan Mason 《European Journal of Sport Science》2019,19(6):784-792

The biomechanical profile of high-level endurance runners may represent a useful model that could be used for developing training programmes designed to improve running style. This study, therefore, sought to compare the biomechanical characteristics of high-performance and recreational runners. Kinematic and kinetic measurements were taken during overground running from a cohort of 14 high-performance (8 male) and 14 recreational (8 male) runners, at four speeds ranging from 3.3 to 5.6?m?s^?1. Two-way ANOVA analysis was then used to explore group and speed effects and principal component analysis used to explore the interdependence of the tested variables. The data showed the high-performance runners to have a gait style characterised by an increased vertical velocity of the centre of mass and a flight time that was 11% longer than the recreational group. The high-performance group were also observed to adopt a forefoot strike pattern, to contact the ground with their foot closer to their body and to have a larger ankle moment. Importantly, although observed group differences were mostly independent of speed, the tested variables showed a high degree of interdependence suggesting an underlying unitary phenomenon. This is the first study to compare high-performance and recreational runners across a full range of kinematic and kinetic variables. The results suggest that high-performance runners maintain stride length with a prolonged aerial phase, rather than by landing with a more extended knee. These findings motivate future intervention studies that should investigate whether recreational runners could benefit from instruction to decrease shank inclination at foot contact.  相似文献   

“三个转型”综合改革：新时代世界一流体育大学发展的历史选择     

曹卫东 《北京体育大学学报》2019,42(1):17-22

摘要：新时代是我国发展新的历史方位，体育强国、教育强国、健康中国三大战略为世界一流体育大学提出了新的更高要求。为此，北京体育大学提出了“三个转型”综合改革，以推进世界一流体育大学建设和高水平竞技体育后备人才培养基地建设，为国家培养勇担新时代体育事业发展重任的优秀人才。为实现上述目标，应在深刻认识“三个转型”改革提出的背景基础上，深入理解“三个转型”的内涵与目标，全面推进“三个转型”综合改革，为新时代体育、教育事业贡献北京体育大学的力量。研究背景包括：1）新时代是“三个转型”的历史坐标，2）强国战略是“三个转型”的现实依据，3）创新模式是“三个转型”的客观需要；“三个转型”分别是：1）全面推进从传统经验型体育大学向现代科技型体育大学转型，2）从以夏季项目为主的体育大学向夏季冬季项目全面发展的体育大学转型，3）从本土化体育大学向国际化体育大学转型，其目的是实现两大办学目标：1）把北京体育大学建成中国高水平竞技体育后备人才培养基地，2）把北京体育大学建设成为世界一流体育大学；为了实现“三个转型”转型及其目标，必须准确把握“办大学与建基地、文化传承与科技创新、立足中国与放眼世界”三个维度及其核心关键问题。  相似文献   

基于单向流固耦合的不同风速下帆板帆翼空气动力性能仿真     

雷晓珊  马勇  蔺世杰 《武汉体育学院学报》2019,53(11):95-100

目的：探究不同风速对帆板帆翼结构以及周围流场的影响。方法：以奥运女子级别的Neil Pryde RS：X帆板帆翼为研究对象，考虑空气动力与结构的流固耦合效应，利用ANSYS Workbench进行单向流固耦合分析。结果：Realizable模型适合计算帆翼周围的流场湍流度，在风速为2m/s时帆翼升阻比最大；随着风速的增大，帆翼面发生变形和振动会导致风激振现象、背风面产生明显的涡脱现象，且帆翼表面应力区增大，全帆的应变逐步增加。结论：不同风速下的帆翼迎风面和背风面的压力分布、帆翼整体空气动力有一定差异，运动员比赛中应该根据当时风况调整帆翼参数。  相似文献   

聚力探索特色小镇 开辟体产全新格局——北京大学第9届中国体育产业高峰论坛综述     

赵雯婷  丁怡清  封英  张锐 《北京体育大学学报》2019,42(2):95-102

摘要：习近平总书记在十九大报告中出要广泛开展全民健身活动，加快推进体育强国建设。随着“健康中国”上升为国家战略、居民消费升级需求日益加深，我国运动休闲特色小镇的发展路径显得尤为重要。在此背景下，专家学者和业界名流齐聚北京大学，集思广益、畅所欲言，为特色小镇献计献策，共商特色小镇建设合作大计。此次中国体育产业高峰论坛分论坛以“运动休闲特色小镇”为主题，对运动休闲特色小镇这个概念进行了全方位、系统性的深刻剖析，并结合运动休闲特色小镇相关成功实践经验，从前期策划、设计、投资到后期的建设、运营，再到内容为王、跨界融合、聚集建构效应，多层次、多角度阐释了运动休闲特色小镇建构的内在机理和方法，为建设运动休闲特色小镇事业，开创全新体育文化产业格局提供了切实可行的路径。  相似文献   

Exploring mechanisms of rapid automatized naming to arithmetic skills in Chinese primary schoolers     

Yiji Wang  Xiaolin Ye  Ciping Deng 《Psychology in the schools》2020,57(4):556-571

Rapid automatized naming (RAN) is associated with children's arithmetic performance, which is multifactorial by nature and consists of arithmetic fluency, arithmetic procedure, and word problems. Yet, it is unclear whether RAN can predict all key aspects of arithmetic skills independently and what cognitive mechanisms may explain this relation. Using a sample of Chinese primary school students (N = 170), results showed that while RAN was associated with all key aspects of arithmetic skills, the relations of RAN–arithmetic procedure and RAN–word problems may be dependent on that of RAN–arithmetic fluency. Supporting the processing speed hypothesis, results further suggested that processing speed may underlie the relation between RAN and arithmetic performance. Findings made unique contribution to understanding the effect of RAN on arithmetic performance and cognitive mechanisms that may underpin this association in the context of Chinese culture.  相似文献   

Power training in elite young soccer players: Effects of using loads above or below the optimum power zone     

Irineu Loturco  Lucas A. Pereira  Valter P. Reis  Chris Bishop  Vinicius Zanetti  Pedro E. Alcaraz 《Journal of sports sciences》2020,38(11-12):1416-1422

ABSTRACT

This study aimed to examine the effects of two jump squat (JS) training programs involving different loading ranges in under-20 soccer players during a preseason period. Twenty-three elite young soccer players performed sprint speed (at 5-, 10-, and 20-m), change-of-direction (COD) speed, JS peak-power (PP), and countermovement jump (CMJ) tests pre and post four weeks of training. Athletes were pair-matched in two groups according to their optimum power loads (OPL) as follows: lower than OPL (LOPL; athletes who trained at a load 20% lower than the OPL) and higher than OPL (HOPL; athletes who trained at a load 20% higher than the OPL). Magnitude-based inferences were used to compare pre- and post-training measures. Meaningful increases in the PP JS were observed for both groups. Likely and possible improvements were observed in the 5- and 10-m sprint velocity in the LOPL group. Meanwhile, possible and likely improvements were observed in the CMJ, 5- and 10-m sprint velocity, and COD speed in the HOPL group. Overall, both training schemes induced positive changes in athletic performance. Soccer coaches and sport scientists can implement the JS OPL-based training schemes presented here, either separately or combined, to improve the physical performance of youth soccer players.  相似文献   

Is academic tracking related to gains in learning competence? Using propensity score matching and differential item change functioning analysis for better understanding of tracking implications     

《Learning and Instruction》2020

This study analyzes gains in cognitive components of learning competence with respect to cohorts based on ability tracking in a Czech longitudinal study. Propensity score matching is used to form parallelized samples of academic and non-academic track students and to eliminate the effect of selective school intake. We applied regression models on the total scores to test for the overall track effect. Furthermore, we analyze scores and gains on the subscores and check for differential item functioning in Grade 6 and in change to Grade 9. While after 3 years, no significant difference between the two tracks was apparent in the total learning competence score, we did, however, find significant differences in some subscores and in the functioning of some items. We argue that item-level analysis is important for deeper understanding of the tracking implications and may provide the basis for more precise evidence-based decisions regarding the tracking policy.  相似文献