Coordination as a function of skill level in the gymnastics longswing     

Genevieve K.R. Williams  Gareth Irwin  David G. Kerwin  Joseph Hamill  Richard E. A. Van Emmerik  Karl M. Newell 《Journal of sports sciences》2016,34(5):429-439

The purpose of this study was to investigate the nature of inter-joint coordination at different levels of skilled performance to: (1) distinguish learners who were successful versus unsuccessful in terms of their task performance; (2) investigate the pathways of change during the learning of a new coordination pattern and (3) examine how the learner’s coordination patterns relate to those of experts in the longswing gymnastics skill. Continuous relative phase of hip and shoulder joint motions was examined for longswings performed by two groups of novices, successful (n = 4) and unsuccessful (n = 4) over five practice sessions, and two expert gymnasts. Principal component analysis showed that during longswing positions where least continuous relative phase variability occurred for expert gymnasts, high variability distinguished the successful from the unsuccessful novice group. Continuous relative phase profiles of successful novices became more out-of-phase over practice and less similar to the closely in-phase coupling of the expert gymnasts. Collectively, the findings support the proposition that at the level in inter-joint coordination a technique emerges that facilitates successful performance but is not more like an expert’s movement coordination. This finding questions the appropriateness of inferring development towards a “gold champion” movement coordination.  相似文献   

Muscle coordination during breaststroke swimming: Comparison between elite swimmers and beginners     

João R. Vaz  Bjørn Harald Olstad  Jan Cabri  Per-Ludvik Kjendlie  Pedro Pezarat-Correia  François Hug 《Journal of sports sciences》2016,34(20):1941-1948

The present study aimed to compare muscle coordination strategies of the upper and lower limb muscles between beginners and elite breaststroke swimmers. Surface electromyography (EMG) of eight muscles was recorded in 16 swimmers (8 elite, 8 beginners) during a 25 m swimming breaststroke at 100% of maximal effort. A decomposition algorithm was used to identify the muscle synergies that represent the temporal and spatial organisation of muscle coordination. Between-groups indices of similarity and lag times were calculated. Individual muscle patterns were moderately to highly similar between groups (between-group indices range: 0.61 to 0.84). Significant differences were found in terms of lag time for pectoralis major (P < 0.05), biceps brachii, rectus femoris and tibialis anterior (P < 0.01), indicating an earlier activation for these muscles in beginners compared to elites (range: ?13.2 to ?3.8% of the swimming cycle). Three muscle synergies were identified for both beginners and elites. Although their composition was similar between populations, the third synergy exhibited a high within-group variability. Moderate to high indices of similarity were found for the shape of synergy activation coefficients (range: 0.63 to 0.88) but there was a significant backward shift (?8.4% of the swimming cycle) in synergy #2 for beginners compared to elites. This time shift suggested differences in the global arm-to-leg coordination. These results indicate that the synergistic organisation of muscle coordination during breaststroke swimming is not profoundly affected by expertise. However, specific timing adjustments were observed between lower and upper limbs.  相似文献   

Comparison of range of motion tests with throwing kinematics in elite team handball players     

Roland van den Tillaar 《Journal of sports sciences》2016,34(20):1976-1982

The aim of this study was to compare the active and passive range of motion (ROM) of the glenohumeral external rotation with the maximal external rotation and throwing performance during different throws with different wind-up techniques in elite team handball players. Twenty-two elite team handball players participated in the study in which the maximal ball release velocity and maximal external rotation during standing, with run-up and jump throws with two types of wind-ups were measured together with the maximal active and passive glenohumeral ROM of the external rotation, lying supine on a bench. Higher maximal external rotation was found during the throws with the whip-like wind-up in comparison to circular-like wind-up throws together with a lower external rotation during the active ROM test. No correlations were found between the ROM of the external rotation with the maximal ball release velocity and the maximal external rotation measured during the throws. It was concluded that ROM of the external rotation measured on the bench does not give any information about the maximal throwing performance or the external rotation angle during throwing and therefore cannot be used to identify potential fast throwers or injuries in elite team handball players.  相似文献   

女大学生协调能力培养之我见     

张林凤 《湖州师范学院学报》2003,25(3):122-124

在高校体育教学中有目的地培养女大学生身体协调能力，对提高女大学生运动技能、身体素质、运动能力等具有良好的促进作用。  相似文献   

基于网络的协同式教学方式初探     

宋英杰  冯继香 《鸡西大学学报》2007,7(5):10-10,55

本文通过对远程教育和基于Internet环境下教学方式的特点的研究和分析,提出了基于Internet的一种新的教学方式—协同式教学方式,并在此基础上讨论了该教学方式的运作方法、优缺点和发展前景。  相似文献   

区域经济协调发展的重大举措   总被引：3，自引：0，他引：3  

谢永萍 《喀什师范学院学报》2005,26(1):15-18

“振兴东北”的战略构想,是在我国进入现代化建设新的发展阶段作出的重大战略决策和战略部署,具有重大的经济意义和政治意义,为此,主要论述了实施“东北战略”的背景、条件和措施。  相似文献   

机器人无标定手眼协调方法研究     

盛荣  孙首群  焦玉格  叶其含 《教育技术导刊》2020,19(5):23-28

无标定情况下的视觉定位是机器人视觉伺服领域的热点和难点。提出一种基于快速自适应滤波的机器人无标定手眼协调方法。首先根据机器人三维基坐标建立运动空间和图像特征空间的微分映射关系,在不预先标定视觉传感器与机器人参数情况下,设计一个直接估计增益矩阵 Kk 的自适应滤波器,在线辨识图像雅可比矩阵。采用最小二乘法获得状态估计的初始值,在此基础上设计视觉控制器和计算运动控制量。在 MAT?LAB 环境下建立机器人手眼协调控制系统仿真模型,将该方法用于观测噪声统计特性未知情况下的定位反馈,并对机器人空间螺旋运动的跟踪情况进行分析。实验结果表明,该自适应滤波器能够完成不规则环境下视觉引导的追踪任务,定位效果优于常规卡尔曼滤波和 Sage-Husa 自适应滤波,具有较强的鲁棒性。  相似文献   

中国农村基础教育乱收费问题的根源——教育体制改革与财政体制改革失调     

蒋晓蕙  施建宁 《集美大学学报(教育科学版》2007,8(1):15-18,46

中国新农村建设离不开教育的发展。目前在中国已受到广泛置疑的教育收费问题,则是中国农村可持续发展的一大瓶颈。财政体制改革与教育体制改革不协调导致基础教育收费不合理,其根本治理应聚焦体制改革的协调推进。财政体制改革与教育体制改革平行式推进,能减少财政与教育体制改革的不协调成本。要注重提高县级财政支持基础教育的能力和保障程度,完善基础教育经费财政转移支付制度。  相似文献   

淮安市物流业与区域经济联动发展耦合协调度分析     

戴澍 《江苏经贸职业技术学院学报》2020,(2):10-13

从物流规模、物流资源、物流布局的维度构建淮安市物流业发展指标体系,从经济基础、居民生活、经济发展潜力、绿色经济等四个方面构建淮安市经济发展指标体系,对淮安市物流业发展与区域经济进行耦合度与耦合协调度分析,确定两者间的耦合关系。在此基础上,提出促进淮安市物流业与区域经济良性互动的建议。  相似文献   

独立光储直流微网母线电压分层协调控制策略     

康家玉  白一锴  王素娥  张晓飞 《实验室研究与探索》2020,(3):62-66

提出一种基于双蓄电池储能系统的电压分层协调控制策略,以储能系统为主体协调控制母线电压稳定。根据母线电压的变化范围将系统的动态调节过程划分为稳态阶段与暂态阶段。稳态阶段下,采用双蓄电池组共同协调工作方式,解决了负载突变导致单组蓄电池充放电电流过大,易引起过流故障的问题;暂态阶段下,采用基于改进下垂控制的双蓄电池组轮换协调工作方式,解决了单组蓄电池荷电状态(State of Charge,SOC)达到上、下限后,出现过充或过放情况引起的蓄电池损坏问题。利用Matlab/Simulink平台分别对系统的两种动态调节过程进行仿真,验证各阶段下所提出的工作方式的有效性,并通过单、双蓄电池组的对比,验证所提出控制策略的合理性与优越性。  相似文献