Coordination pattern of baseball pitching among young pitchers of various ages and velocity levels

This study compared the whole-body movement coordination of pitching among 72 baseball players of various ages and velocity levels. Participants were classified as senior, junior, and little according to their age, with each group comprising 24 players. The velocity levels of the high-velocity (the top eight) and low-velocity (the lowest eight) groups were classified according to their pitching velocity. During pitching, the coordinates of 15 markers attached to the major joints of the whole-body movement system were collected for analysis. Sixteen kinematic parameters were calculated to compare the groups and velocity levels. Principal component analysis (PCA) was conducted to quantify the coordination pattern of pitching movement. The results were as follows: (1) five position and two velocity parameters significantly differed among the age groups, and two position and one velocity parameters significantly differed between the high- and low-velocity groups. (2) The coordination patterns of pitching movement could be described using three components, of which the eigenvalues and contents varied according to age and velocity level. In conclusion, the senior and junior players showed greater elbow angular velocity, whereas the little players exhibited a wider shoulder angle only at the beginning of pitching. The players with high velocity exhibited higher trunk and shoulder rotation velocity. The variations among groups found using PCA and kinematics parameter analyses were consistent.     

英国超市消费现象分析及其启示

英国超市消费逐年增长 ,其经营方式更加灵活 ,销售领域更加广泛。中国是一个人口大国 ,随着居民收入水平的不断提高 ,消费水平也必然不断提高 ,如何使我国超市消费成为新的消费热点 ,引导超市经营向良性发展 ,我们可以透过英国超市消费现象 ,得到很好的启迪     

区域经济协调：西部基础设施建设中值得注意的问题

西部基础设施建设是一个系统工程,是西部经济发展的物质条件,也是全国经济和社会发展总系统的重要组成部分,各区域协调发展,任重道远。西部基础设施建设必须注意以下几方面的协调:科学规划,统筹协调;区域开发与突出重点协调;基础设施建设与非基础设施建设协调;基础设施建设与生态保护协调;城市基础设施建设与农村基础设施建设协调。     

蔬菜供应链利益分配问题初探

蔬菜供应链中各节点企业的风险承担和利益分配不均衡。要合理解决上述问题,就必须规范蔬菜供应链运营环境,加速蔬菜供应链中各企业之间的信息流通,培育蔬菜龙头企业品牌,促进企业做大做强。     

土地征用制度的经济学分析及改革思路

从经济学角度出发，运用生产者与消费者剩余，分析了土地征用制度的市场效率；指出现行制度供给不足是导致征地权滥用与征地行为不规范的根源；并指出制度的“路径依赖”性导致制度变迁的阻力较大。鉴于此，提出了改革的两种思路——完善土地征用制度和规范土地流转市场。当前应完善土地征用制度，随着经济发展与制度环境的改善，再过渡到全面改革土地征用制度上。     

工程电流源综述

在信号变换及电子测量中，电流源应用广泛，其性能优劣及结构特点对测量结果有直接影响。因此，在电子测量控制工程设计中应正确选用电流源电路结构及参数。     

感性设备同名端的判断

本文介绍了一些常见感性设备同名端判断的方法,对其正确使用和维护有重要的实际意义。     

“尊重学生”的管理机制

为了使尊重学生的原则落到实处,需要教育管理制度的保证。为此,学校可以尝试在管理机制上进行改进,包括施行组织结构扁平化,内部顾客链和倒金字塔组织模式,双向闭合评价模式。为使这些管理机制有效发挥作用,学校应该从整个制度建设出发系统考虑。     

对和谐社会中人际和谐的理解

构建和谐社会,就是要实现全社会人与人融洽相处,人与自然和谐共存。和谐社会的主体是人,和谐的人际关系是和谐社会的重要基础,没有人与人之间的和谐就无所谓社会的和谐。本文分析了和谐社会的人际关系,全文分为两部分,第一部分分析了对和谐社会的认识,第二部分分析了人们对和谐社会的人际关系的错误理解。     

协调运用交际教学法和传统教学法

本文针对目前大学专业英语教学中存在的问题，分析了交际教学法与传统教学法的利弊并提出了将两者协调运用的方法。