青少年足球运动员的速度力量训练     

杨大强 《体育成人教育学刊》2002,18(3):84-85

速度力量是速度与力量的综合表现 ,它的提高受速度素质与力量素质的牵制。力量和速度是青少年足球运动员快速能力的决定因素。速度力量的典型表现形式是爆发力、起动力、反应力。提出青少年足球运动员力量素质发展的敏感期与必要性 ,对速度力量的理论与实践作了概述。  相似文献   

世界竞走运动(1991～1998年)发展的状况分析及展望   总被引：4，自引：1，他引：3  

赛庆彬 《北京体育大学学报》2002,25(4):574-576

对1991-1998年、1991-1995年、1996-1998年各阶段世界竞走运动的发展状况进行了分析,结果表明:1995年底竞走定义的修改并未对世界竞走运动的发展产生不良影响,反而更加促进了世界竞走运动的健康发展.展望今后世界竞走运动发展的新思路:充分利用竞走运动的特殊性和人体生物力学界限标准及比赛中裁判员的判罚界限标准进行训练和比赛;改善和提高训练、比赛的方法、手段,特别是高原训练的方法、手段;完善赛前运动员运动能力的控制和比赛中走动节奏的控制;更加重视科学选材及心理训练和恢复训练等都将是今后世界竞走运动发展的趋势.  相似文献   

现代跳远运动员的速度训练     

孟庆袖 《山西师大体育学院学报》2002,17(2):67-68

跳远的起跳技术由打击型、制动型已经发展成速度型(跑步型)。为了适应这种技术,应该重新认识现代跳远运动员的速度训练,它包括发展运动员跑的速度(跑的能力、绝对速度、助跑速度),速度性力量和快速跳跃能力。  相似文献   

Optimal sampling frequency in recording of resistance training exercises     

Paolo Bardella  Irene Carrasquilla García  Marco Pozzo  Julio Tous-Fajardo  Eduardo Saez de Villareal 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(1):102-114

The purpose of this study was to analyse the raw lifting speed collected during four different resistance training exercises to assess the optimal sampling frequency. Eight physically active participants performed sets of Squat Jumps, Countermovement Jumps, Squats and Bench Presses at a maximal lifting speed. A linear encoder was used to measure the instantaneous speed at a 200 Hz sampling rate. Subsequently, the power spectrum of the signal was computed by evaluating its Discrete Fourier Transform. The sampling frequency needed to reconstruct the signals with an error of less than 0.1% was f_99.9 = 11.615 ± 2.680 Hz for the exercise exhibiting the largest bandwidth, with the absolute highest individual value being 17.467 Hz. There was no difference between sets in any of the exercises. Using the closest integer sampling frequency value (25 Hz) yielded a reconstruction of the signal up to 99.975 ± 0.025% of its total in the worst case. In conclusion, a sampling rate of 25 Hz or above is more than adequate to record raw speed data and compute power during resistance training exercises, even under the most extreme circumstances during explosive exercises. Higher sampling frequencies provide no increase in the recording precision and may instead have adverse effects on the overall data quality.  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   

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   

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   

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   

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   

电磁力测量试验台的设计   总被引：2，自引：0，他引：2  

边忠国 《实验技术与管理》2007,24(4):64-65,76

从试验台的结构特点和工作流程入手,介绍了其液压系统的工作原理及特点。实践证明:该系统设计合理、工作可靠、调节控制灵活方便。  相似文献