充分发挥多媒体课件在教学中的优势

多媒体教学通常是围绕“多媒体课件”所展开的一种教学形式。充分发挥多媒体课件教学“信息量大 ,表现力强 ,使用灵活、方便 ,教学效率高”的优势 ,关键是制作好和使用好多媒体课件。本文结合作者多媒体课件教学的经验体会 ,阐述了多媒体课件在课堂教学中的优势 ,介绍了几种流行的多媒体课件 ,较详细地介绍了幻灯片课件的制作和使用方法 ,以及在课堂教学中应处理好的几个关系     

创新和发展是“三个代表”思想的灵魂

中国共产党 83年来的理论创新和具体实践 ,其关键在于与时俱进 ,核心是坚持党的先进性 ,本质在于执政为民 ,灵魂在于创新。在中国共产党奋斗的历史长河中 ,无时不在创新。     

"手"文化及"手"在汉字中的形变

古人从汉字的排列和检索的角度归纳出了部首。“手”在汉字中是偏旁,是部首,是部件。本文探讨了汉字中关于“手”的表示法及其形变的源流,既有历时的梳理,也有共时的比较,同时对现代汉字中“手”的部件的简省、代用和混同现象也有所揭示。     

论“人类实践”与马克思主义理论

＂人类实践＂是马克思主义理论整体生成、创新发展和向前推进的根本之源。解读人类实践是马克思主义理论整体生成的逻辑内核;结合人类实践中的具体情况是马克思主义理论创新发展的根本基础;思考把握人类实践中的和谐状态是当今马克思主义理论向前推进的现实要求。论证＂人类实践＂与马克思主义理论之间的渊源,有利于我们深刻理解和把握马克思主义理论的科学内涵,对我们更好地坚持与发展马克思主义理论具有重大的现实意义。     

Force–velocity characteristics of upper limb extension during maximal wheelchair sprinting performed by healthy able-bodied females

The aim of this study was to determine the relationship between force and velocity parameters during a specific multi-articular upper limb movement – namely, hand rim propulsion on a wheelchair ergometer. Seventeen healthy able-bodied females performed nine maximal sprints of 8?s duration with friction torques varying from 0 to 4?N?·?m. The wheelchair ergometer system allows measurement of forces exerted on the wheels and linear velocity of the wheel at 100 Hz. These data were averaged for the duration of each arm cycle. Peak force and the corresponding maximal velocity were determined during three consecutive arm cycles for each sprint condition. Individual force–velocity relationships were established for peak force and velocity using data for the nine sprints. In line with the results of previous studies on leg cycling or arm cranking, the force–velocity relationship was linear in all participants (r?=??0.798 to ?0.983, P?<0.01). The maximal power output (mean 1.28?W?·?kg^?1) and the corresponding optimal velocity (1.49?m?·?s^?1) and optimal force (52.3?N) calculated from the individual force–velocity regression were comparable with values reported in the literature during 20 or 30?s wheelchair sprints, but lower than those obtained during maximal arm cranking. A positive linear relationship (r?=?0.678, P?<0.01) was found between maximal power and optimal velocity. Our findings suggest that although absolute values of force, velocity and power depend on the type of movement, the force–velocity relationship obtained in multi-articular limb action is similar to that obtained in wheelchair locomotion, cycling and arm cranking.     

Acute responses of biomechanical parameters to different sizes of hand paddles in front-crawl stroke

Abstract

This study investigated the acute effects of different sizes of paddles on the force-time curve during tethered swimming and swimming velocity in front-crawl stroke. Fourteen male swimmers (20.0 ± 3.7 years; 100-m best time: 53.70 ± 0.87 s) performed two 10-s maximal efforts in tethered swimming to obtain peak force, average force, impulse, rate of force development, stroke duration and time to peak force. Swimming velocity, stroke rate and stroke length were obtained from two 25-m maximal swims. Both tests were repeated in five conditions: free swimming, wearing small (280 cm ² ), medium (352 cm ² ), large (462 cm ² ) and extra-large (552 cm ² ) hand paddles. Compared to free swimming, paddles provided significant increases of peak force (medium: 11.5%, large: 16.7%, extra-large: 21.7%), impulse (medium: 15.2%, large: 22.4%, extra-large: 30.9%), average force (medium: 5.1%, large: 7.5%), rate of force development (extra-large: 11.3%), stroke duration (medium: 9.3%, large: 11.8%, extra-large: 18.5%), time to peak force (medium: 11.1%, large: 15.9%, extra-large: 22.1%), swimming velocity (medium: 2.2%, large: 3.2%, extra-large: 3.7%) and stroke length (medium: 9.0%, large: 9.0%, extra-large: 14.8%), while stroke rate decreased (medium: –6.2%, large: –5.5%, extra-large: –9.5%). It is concluded that medium, large and extra-large paddles influence the force-time curve and change swimming velocity, suggesting these sizes may be useful for force development in water.     

Description of the finger mechanical load of climbers of different levels during different hand grips in sport climbing

Abstract

Currently, direct empirical evidence exists about the amount of mechanical load that climbers apply to each finger during several hand grips specific to sport climbing, but not yet in a specific hanging position.

The objectives of this study are a) to draw and build a solid and rigid support that simulates the real action of a hand grip in a hanging position in sport climbing, to enable the measurement of the mechanical load endured by the fingers in a hanging position and in addition, b) to describe the distribution of mechanical load among fingers as a function of the level of climbing during different hand grips in a hanging position.

Thirty young male participants took part in the initial phase of reliability of the measurements, while another 64 male climbers participated in the subsequent study phase to check the relations between independent and dependent variables. The level of on sight climbing and the total practice experience were used to define the groups. The research task consisted of performing hanging positions on the created support in order to measure the mechanical load endured by the fingers in the three most characteristic hand grips in climbing (crimp, half crimp and slope). It has been concluded that the performance level of the climbers had no influence on the production of a pattern of differentiated finger mechanical load during the research task.     

徒手相搏的历史发展研究

文章以我国历史上不同时期徒手相搏的不同名称为主要线索,罗列、整理徒手相搏的发展历史,并分析了各个时期的发展特点.自徒手相搏起源以后,徒手相搏在先秦时期出现了手搏、角力、相搏,徒搏技术已有一定水平并且是军队训练的主要内容;秦汉三国时期徒手相搏开始向多样化方向发展,并将角力更名为角抵,并出现了相扑一词,汉代角抵形成三种风格;隋唐五代十国开始向专门化方向发展,出现了专门的组织机构“相扑朋”、“小儿园”.宋元明清时期徒手相搏进入了全面发展阶段,在宋朝出现了比赛规则和裁判,在比赛技术上都有了很大进步,并且每个朝代都有自己的专门组织机构.发展到了现代,徒手相搏开始进入了科学化、正规化、竞赛化、国际化的发展阶段.     

也论太极推手竞技化——与《论太极推手的技术和文化特性——兼论传统太极推手竞技化不可行》作者商榷

通过与《论太极推手的技术和文化特性——兼论传统太极推手竞技化不可行》作者商榷,对该文作者提出太极推手仅适用于"对练运动形式"提出质疑。认为现代太极推手运动源于传统习练太极拳之"用"的练习,体现了对传统的继承和创新,传统的太极推手练习不乏对抗性,太极推手竞技化可行,传统与现代并重并不矛盾,并对竞技太极推手的继续开展提出看法和建议。     

太极拳和交谊舞对中老年人骨密度及柔韧性的对比研究

采用文献资料法、实验法和数理统计法,对成都市武侯区部分部分参加太极拳和交谊舞锻炼的离退休职工（家属）和一般居民进行了调查、研究、分析。结果显示：太极拳男组身体的柔韧性明显大于交谊舞男组（P〈0.05）,太极拳女组身体的柔韧性也稍大于B女组,但两组的差异性不显著;太极拳男组和交谊舞男组,太极拳女组和交谊舞女组在骨密度的比较上（P〉0.05）没有明显差别,说明太极拳和交谊舞在减少体内骨矿物质的自然丢失,保持骨密度稳定,防止骨质疏松方面的健身功效是相同的。