U17足球运动员专项灵敏和耐力素质分析及评价等级的建立     

陈翀  陈效科  王朝信  王启荣 《北京体育大学学报》2016,39(11):112-118

摘要：目的：分析我国优秀U17足球运动员专项灵敏和耐力素质，并建立评价等级标准。主要运用场地测试法、数理统计法，对全国优秀的U17男子足球运动员进行专项灵敏和耐力素质测试和分析，分析结果为：1）按照优良中下差等级划分标准，曲线跑为9.05s以下、9.06~9.40s、9.41~10.20s、10.21~10.70s、10.71s以上；四线往返跑为9.60s以下、9.61~9.90s、9.91~10.60s、10.61~10.90s、10.91s以上。YOYO间歇性耐力跑为3601m以上、3231~3600m、2201~3230m、1951~2200m、1950m以下；2）平均值方面，曲线跑为9.88±0.66s；四线往返跑为10.27±0.53s；YOYO间歇性耐力跑为2754.30±672.37m。得出以下结论：1）足球运动中，曲线跑和四线往返跑是反映专项灵敏的代表性指标，YOYO间歇性耐力跑是反映专项耐力的代表性指标。运用离差法可以客观准确的建立足球运动员专项灵敏和专项耐力评分表和评价等级标准。2）我国U17男子足球运动员的专项灵敏和耐力水平分布比较分散，其位置特征总体表现为专项灵敏素质：前锋>前卫>守门员>后卫；专项耐力素质：前卫>后卫 >前锋>守门员。  相似文献   

A Process for Reviewing and Evaluating Generated Test Items     

Mark J. Gierl  Hollis Lai 《Educational Measurement》2016,35(4):6-20

Testing organization needs large numbers of high‐quality items due to the proliferation of alternative test administration methods and modern test designs. But the current demand for items far exceeds the supply. Test items, as they are currently written, evoke a process that is both time‐consuming and expensive because each item is written, edited, and reviewed by a subject‐matter expert. One promising approach that may address this challenge is with automatic item generation. Automatic item generation combines cognitive and psychometric modeling practices to guide the production of items that are generated with the aid of computer technology. The purpose of this study is to describe and illustrate a process that can be used to review and evaluate the quality of the generated item by focusing on the content and logic specified within the item generation procedure. We illustrate our process using an item development example from mathematics drawn from the Common Core State Standards and from surgical education drawn from the health sciences domain.  相似文献   

腰痛羽毛球运动员的功能评估          下载免费PDF全文

李男  檀志宗  叶晶龙  刘新宇  任雪 《体育科研》2017,(6):82-86

研究目的：对腰痛羽毛球运动员的部分功能进行测试，观察其活动范围、肌肉力量、肌电活动以及相应对称性。为了解羽毛球运动员损伤机制发生提供科学依据。研究对象：6名腰痛羽毛球运动员（男运动员4名，女运动员2名）。研究方法：对研究对象分别进行日本矫正外科协会（JOA）评分量表、躯干旋转、胸椎旋转、髋关节内外旋活动度、躯干等速旋转力量、等长背伸活动的肌电活动测试，并观察两侧差异比的平均值。研究结果：（1）腰痛运动员的躯干旋转、胸椎旋转以及髋关节外旋活动度平均差异比为（31.98±21.53）%，（19.8±17.08）%，（13.81±4.43）%大于10%，仅髋关节内旋活动度平均差异比为（5.62±5.63）%小于10%。胸椎和髋关节旋转动度有减小的趋势；（2）等速躯干旋转两侧峰力矩和平均功率差异没有显著性意义，峰力矩平均差异比为（5.45±1.78）%小于10%，而平均功率平均差异比为（12.78±11.40）%大于10%；（3）在等长背伸活动中，竖脊肌肌电活动的平均两侧差异比为（14.18±9.84）%大于10%，而多裂肌肌电活动的平均两侧差异比（9.90±7.92）%接近10%；竖脊肌和多裂肌的中位频率斜率（Median Frequency slope，MFs）均出现下降的趋势，但两侧差异比为（4.68±3.17）%，（5.35±5.40）%小于10%。结论：（1）腰痛羽毛球运动员躯干旋转、胸椎旋转、髋关节外旋活动范围存在对称性问题，且胸椎旋转、髋关节旋转有减少趋势；（2）躯干等速旋转平均功率存在对称性问题；（3）等长背伸任务中，竖脊肌和多裂肌出现疲劳，肌电活动存在对称性问题。  相似文献   

二项展开式中项的几个性质     

姜学杰 《甘肃高师学报》2011,16(5):66-67

通过构造二项式项三角形和项平行四边形,揭示了项的递推关系、项三角形中的三向和、项平行四边形中项的对称性规则及项的有关微分性质.  相似文献   

倒伏对春小麦品种(品系)籽粒灌浆特性及产量的影响     

马勇  邵立刚  王岩  李长辉  车京玉  高凤梅  张起昌 《河南科技学院学报》2006,34(3):15-18,20

试验选取三类不同熟期的春小麦品种（品系），在同一时间倒伏后，分期对比测定各品种（品系）倒伏后不同发育阶段的籽粒鲜重、干重，比较分析品种（品系）倒伏与未倒伏籽粒的灌浆特性及干物质积累变化规律。结果表明：倒伏对不同品种（品系）籽粒干物质积累动态变化的差异显著性影响不同，对同一品种（品系）的最大灌浆速率及到达最大灌浆速率的时间均存在着影响，最终对籽粒产量存在着不同程度的影响。  相似文献   

数控教学方法的设计与探讨     

刘英超 《中国教育技术装备》2007,(11):26-28

数控技术是一门相对新兴的学科,同时也是一门难于掌握和讲授的实用型科目。数控技术将成为现代制造技术的核心技术,因此培养实用型数控技术人才迫在眉睫,职业院校的教师不得不思考如何提高数控教学的质量,让学生能够欣然、自主地学到真正的技能,最终服务于社会。基于这样一种思考,对数控课程的教学方法进行探讨与设计,宗旨是以教助学,以学促教,师生互动,共同进步。  相似文献   

The acute testosterone,growth hormone,cortisol and interleukin-6 response to 164-km road cycling in a hot environment     

Jakob L. Vingren  Ronald G. Budnar Jr.  Amy L. McKenzie  Anthony A. Duplanty  Hui-Ying Luk  Danielle E. Levitt 《Journal of sports sciences》2016,34(8):694-699

This study investigated the acute endocrine responses to a 164-km road cycling event in a hot environment. Thirty-four male experienced cyclists (49.1 ± 8.3 years, 86.8 ± 12.5 kg, 178.1 ± 5.1 cm) participating in a 164-km road cycling event were recruited. Blood samples were collected within 0.3–2.0 h before the start (PRE: ~0500–0700 h) and immediately following the ride (POST). Samples were analysed for testosterone, growth hormone (GH), cortisol and interleukin-6 (IL-6). The temperature and humidity during the event were 35.3 ± 4.9°C and 47.2 ± 14.0%, respectively. Based on the finishing time, results for the fastest (FAST, 305 ± 10 min) and the slowest (SLOW, 467 ± 31 min) quartiles were compared. At POST, testosterone concentration was significantly (P < 0.05) lower (PRE, 20.8 ± 8.6; POST, 18.2 ± 6.7 nmol · L^?1), while GH (PRE, 0.3 ± 0.1; POST, 2.3 ± 0.3 µg · L^?1), cortisol (PRE, 661 ± 165; POST, 1073 ± 260 nmol · L^?1) and IL-6 (PRE, 4.0 ± 3.4; POST, 22.4 ± 15.2 pg · mL^?1) concentrations were significantly higher than those at PRE. At POST, GH and cortisol were significantly higher for the FAST group than for the SLOW group (GH, 3.6 ± 2.0 and 1.0 ± 0.8 µg · L^?1; cortisol, 1187 ± 209 and 867 ± 215 nmol · L^?1). Participation in an ultra-endurance road cycling event in a hot environment induced significant acute changes in concentrations of circulating hormones, with a greater augmentation of GH and cortisol in those completing the ride fastest.  相似文献   

英语阅读中存在的问题及阅读技巧     

孟凡茂 《临沂师范学院学报》2002,24(2):139-141

阅读课程的目的在于提高学生的阅读理解能力和阅读效率。要提高阅读理解能力和阅读效率，就需使读者克服一些不良的阅读习惯，掌握正确的阅读技巧。采用整体法阅读会大大改善学生的阅读速度和阅读质量。  相似文献   

通风空调工程量清单与计价表中清单项编制的教学探讨     

刘帅 《教育教学论坛》2019,(27):213-215

正确而全面地编制工程量清单与计价表中的清单项是计量与计价教学的重点和难点。本文以某通风空调工程为例,提出了"查表看图"的教学方法,实践证明取得了较好的教学效果。  相似文献   

Effects of glucose–fructose versus glucose ingestion on stride characteristics during prolonged treadmill running     

Patrick B. Wilson  Stacy J. Ingraham 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(3):270-282

Scarce research has examined the effects of carbohydrate composition on running stride characteristics. On two occasions, 14 males and 6 females completed a 120-min sub-maximal run followed by a 4-mile time trial. Participants consumed glucose (GLU) or glucose–fructose (GLU–FRU) beverages supplying 1.3 g/min carbohydrate. Substrate use, psychological affect [Feeling Scale (FS)], and stride characteristics (stride frequency, stride length, and contact time) were assessed. Effects were expressed as Cohen’s d (90% confidence limits [90% CL]). CLs for stride frequency differences at 53 min (90% CL = 0.04–0.21) and 113 min (90% CL = 0.02–0.24) did not cover 0, indicating a positive effect of GLU–FRU. However, effect sizes were small (d = 0.13) and likely-to-very-likely trivial. Energy expenditure differences at sub-maximal end were very likely trivial (d = 0.08; 90% CL = 0.00–0.17), while FS ratings were possibly higher for GLU–FRU at 50 (d = 0.19; 90% CL = ?0.10–0.48) and 110 min (d = 0.16; 90% CL = ?0.13–0.45). During the time trial, stride length was possibly higher with GLU–FRU (d = 0.13; 90% CL = ?0.08–0.33). Glucose–fructose co-ingestion has no significant effect on stride characteristics during constant-velocity running but may result in slightly higher stride length during self-paced running.  相似文献