纠正轮滑直道前滑向后蹬地错误动作的方法初探     

刘锋  高占江  刘彤卫 《吉林体育学院学报》2010,26(2):75-76

运用文献资料法、对照实验法、数理统计法、归纳分析等研究方法,对在教授初学者时采用的摆动腿直接向支撑腿拉回的收腿技术上附加＂靠脚＂动作条件限制的作用进行分析。结果表明附加＂靠脚＂动作条件限制的实验组向后蹬地动作发生率明显低于对照组。  相似文献   

Effects of different instructional constraints on task performance and emergence of coordination in children     

《European Journal of Sport Science》2013,13(3):224-232

Abstract

The objectives of this study were to determine the impact of different instructional constraints on standing board jump (sbj) performance in children and understand the underlying changes in emergent movement patterns. Two groups of novice participants were provided with either externally or internally focused attentional instructions during an intervention phase. Pre- and post-test sessions were undertaken to determine changes to performance and movement patterns. Thirty-six primary fourth-grade male students were recruited for this study and randomly assigned to either an external, internal focus or control group. Different instructional constraints with either an external focus (image of the achievement) or an internal focus (image of the act) were provided to the participants. Performance scores (jump distances), and data from key kinematic (joint range of motion, ROM) and kinetic variables (jump impulses) were collected. Instructional constraints with an emphasis on an external focus of attention were generally more effective in assisting learners to improve jump distances. Intra-individual analyses highlighted how enhanced jump distances for successful participants may be concomitant with specific changes to kinematic and kinetic variables. Larger joint ROM and adjustment to a comparatively larger horizontal impulse to a vertical impulse were observed for more successful participants at post-test performance. From a constraints-led perspective, the inclusion of instructional constraints encouraging self-adjustments in the control of movements (i.e., image of achievement) had a beneficial effect on individuals performing the standing broad jump task. However, the advantage of using an external focus of attentional instructions could be task- and individual-specific.  相似文献   

Validity and reliability of kick count and rate in freestyle using inertial sensor technology     

Sacha K. Fulton  David B. Pyne  Brendan Burkett 《Journal of sports sciences》2013,31(10):1051-1058

Abstract

In freestyle swimming the arm action is routinely quantified by stroke count and rate, yet no method is currently available for quantifying kick. In this study, we assessed the validity and reliability of inertial sensor technology (gyroscope) to assess kick count and rate. Twelve Paralympic swimmers completed a 100-m freestyle-swimming time-trial and freestyle kicking-only time-trial three times each in a season. An algorithm was developed to detect the up and down beat of individual kicks from the gyroscope trace. For comparative purposes, underwater video analysis provided the criterion measure. The standard error of the estimate (validity) for kick count, expressed as a coefficient of variation, was 5.9% (90% confidence interval 5.5 to 6.4) for swimming, and 0.6% (0.5 to 0.6) for kicking-only trials. The mean bias for kick count was ?1.7% (?2.4 to ?1.1) for swimming, and ?0.1% (?0.2 to ?0.1) for kicking-only trials. Correlations between the sensor and video for kick count were 0.96 (0.95 to 0.97) for swimming, and 1.00 (1.00 to 1.00) for kicking-only trials. The typical error of the measurement (reliability) between trials was approximately 4% for kick count and rate. The inertial sensors and associated software used generated sufficient validity and reliability estimates to quantify moderate to large changes in kick count and rate in freestyle swimming.  相似文献   

Markers of isometric training intensity and reductions in resting blood pressure     

Gavin R. Devereux  Jonathan D. Wiles  Ian Swaine 《Journal of sports sciences》2013,31(7):715-724

Abstract

In this study, we examined the correlations between selected markers of isometric training intensity and subsequent reductions in resting blood pressure. Thirteen participants performed a discontinuous incremental isometric exercise test to volitional exhaustion at which point mean torque for the final 2-min stage (2min-torque_peak) and peak heart rate peak (HR_peak) were identified. Also, during 4 weeks of training (3 sessions per week, comprising 4 × 2 min bilateral leg isometric exercise at 95% HR_peak), heart rate (HR_train), torque (Torque_train), and changes in EMG amplitude (ΔEMG_amp) and frequency (ΔEMG_freq) were determined. The markers of training intensity were: Torque_train relative to the 2min-torque_peak (%2min-torque_peak), EMG relative to EMG_peak (%EMG_peak), HR_train ΔEMG_amp, ΔEMG_freq, and %MVC. Mean systolic (?4.9 mmHg) and arterial blood pressure (?2.7mmHg) reductions correlated with %2min-torque_peak (r = ?0.65, P = 0.02 and r = ?0.59, P = 0.03), ΔEMG_amp (r = 0.66, P = 0.01 and r = 0.59, P = 0.03), ΔEMG_freq (r = ?0.67, P = 0.01 and r = ?0.64, P = 0.02), and %EMG_peak (systolic blood pressure only; r = ?0.63, P = 0.02). These markers best reflect the association between isometric training intensity and reduction in resting blood pressure observed after bilateral leg isometric exercise training.  相似文献   

以运动学为视角分析核心力量训练对男子跳高运动员助跑最后一步和起跳阶段摆动腿的积极影响     

张萍 《体育科技文献通报》2013,21(6):49-50

本文以广州体育学院田径队5名男子运动员为研究对象,进行20周的核心力量训练,通过三维摄影对实验前后跳高运动员在助跑最后一步和起跳阶段摆动腿的支撑与摆动技术的运动学特征进行分析发现：起跳腿着地时摆动腿摆动的角速度、起跳蹬伸阶段摆动腿最大角速度及身体重心水平速度增加值等差异显著。  相似文献   

站姿振动对血液粘度的影响     

徐树礼  张雪临  闫之朴 《辽宁体育科技》2013,35(2):29-31

目的:探讨站姿振动和传统力量训练后,血液粘度的变化特征和生理学机制。方法:运动训练专业21名志愿者,在站姿振动或传统训练条件下,负重深蹲训练12周,测试血液粘度4次。结果:实验组的全血低切粘度、高频低振幅组的全血高切粘度、全血相对粘度和全血高切还原粘度明显增高,均与对照组差异显著。结论:站姿振动使血液粘度增大,其中高频低振幅振动的影响更早、更明显,应科学选择振动训练参数和提高医务监督能力。  相似文献   

浅析如何提高我国短跑运动员途中跑的能力     

薛红 《大连大学学报》2003,24(6):66-68,71

途中跑技术在田径短距离跑项目中是最重要的一个技术环节,对短跑成绩起决定作用. 目前,我国短跑运动停滞不前,关键一环是运动员途中跑的能力没有得到有效的提高.通过和世界优秀运动员的比较,从运动技术、运动能力、能量供应等不同角度,分析影响我国短跑运动员途中跑能力的问题所在,提出解决的有效途径,供大家在以后的教学训练中参考.  相似文献   

常任制：确保党代会权力机关地位的制度保障   总被引：3，自引：0，他引：3  

彭建军  毛政相 《湖南师范大学社会科学学报》2006,35(3):56-60

党代会应当是同级党组织惟一最高权力机关。但是现行党代会制度下，党代会的应有地位没有得到充分有效的保障，我们在大量调查研究的基础上，从党代会职权的三级弱化、党员权利的三次弱化、纪检机关职权的二级弱化三个方面探究了其中的原因。并进一步论证了党代会常任制是执政的中国共产党科学执政、民主执政、依法执政的必然选择，是确保党代会最高权力机关地位的制度保障。  相似文献   

二能级原子在高斯驻波中所受辐射力     

敖胜美  曾高坚 《湖南师范大学教育科学学报》1996,(5)

计算在高斯分布的弱电磁驻波中沿Ｚ轴方向运动的二能级原子所受的辐射力，并讨论近共振情况下高斯驻波对原子的作用．说明下失谐（△＜０）时，高斯驻波有可能冷却和囚禁二能级原子．  相似文献   

对背越式跳高摆动腿技术的探析     

梁向东 《桂林师范高等专科学校学报》2012,26(2):183-186

运用文献资料法、比较法、数理统计法和逻辑推理法对背越式跳高的起跳过程进行分析,阐释了起跳过程中摆动腿的摆动是否做到位,将影响到跳高的效果,揭示了在起跳过程中摆动腿的摆动动作对跳高成绩具有重要的影响。  相似文献