关于增强掷拨铅球力量的研究

铅球教学与训练,主要技术是持球,滑步,最后用力拨球和球出手后维持身体平衡几个部分,而用力掷拨球又是决定运动成绩好坏的关键。为提高上肢力量,在掷拨球教学中采用提拉式,上推式和吊球拨球法进行练习,不仅提高运动机能,而对提高身体素质,增加上肢肌群的爆发力量,有着重要作用。通过实践,实验对比,明显提高了运动成绩。该方法不仅适用教学,而且对训练也有指导价值,并具有一定的科学意义。     

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.     

A quantitative evaluation of the high elbow technique in front crawl

Many coaches often instruct swimmers to keep the elbow in a high position (high elbow position) during early phase of the underwater stroke motion (pull phase) in front crawl, however, the high elbow position has never been quantitatively evaluated. The aims of this study were (1) to quantitatively evaluate the “high elbow” position, (2) to clarify the relationship between the high elbow position and required upper limb configuration and (3) to examine the efficacy of high elbow position on the resultant swimming velocity. Sixteen highly skilled and 6 novice male swimmers performed 25 m front crawl with maximal effort and their 3-dimensional arm stroke motion was captured at 60 Hz. An attempt was made to develop a new index to evaluate the high elbow position (I_he: high elbow index) using 3-dimensional coordinates of the shoulder, elbow and wrist joints. I_he of skilled swimmers moderately correlated with the average shoulder internal rotation angle (r = ?0.652, P < 0.01) and swimming velocity (r = ?0.683, P < 0.01) during the pull phase. These results indicate that I_he is a useful index for evaluating high elbow arm stroke technique during the pull phase in front crawl.     

Comparative study between fully tethered and free swimming at different paces of swimming in front crawl

Tethered swimming is a method often used to measure or enhance the physical and technical resources of swimmers. Although it is highlighted that the technique used in tethered swimming is probably different from that used in free conditions, there are few comparative studies on this subject. The current study aims to compare fully tethered and free swimming based on kinematic hand parameters (orientation, velocity and acceleration of the hand, sweepback and angle of attack), which are known to act directly on the generation of propulsive forces. The results show that there are significant differences during the stretch and catch phases but less during the insweep and upsweep phases. Tethered swimming makes it possible to estimate the propelling forces generated by the hand in free swimming at distance and middle-distance paces, but overestimates it at sprint pace. However, in view of the modifications of the kinematic parameters, it should not be used under repeated conditions of use, such as for the development of swimmers’ capacity.     

The role of the entry-and-stretch phase at the different paces of race in front crawl swimming

The aim of this study was to determine the role played by the entry-and-stretch phase in the coordination of swimming, at the different paces of race. Three national level swimmers (two men and one woman) were recorded, in lateral and bottom views, in three swimming paces: sprint (50 m and 100 m), middle-distance (200 m and 400 m) and long-distance (800 m and 1500 m). Anatomical landmark positions were obtained by manual digitalisation of the videos. Computational fluid dynamics and experimental studies (with a strain gauge balance and particle image velocimetry method) were used to measure and to calculate the external forces applied to the hand and to the forearm and to visualise the flow around the profile. Entry-and-stretch is the phase which varies the most according to the swimming pace. This phase can be decomposed into two sub-phases: one, the extension forward coordinated with the insweep of the opposite arm, and another one, the rotation downward coordinated with the upsweep. Results show that, at the three paces, this phase is not propulsive and could contribute essentially to maintain the horizontal balance of the body.     

Scandinavian women’s football: the importance of male and female pioneers in the development of the sport

ABSTRACT

The importance of female and male pioneers in the development of women’s football in Scandinavia is in focus, where some of the female pioneers’ experiences presented. Sif Kalvø from Western Norway was the first known Scandinavian female football player who played abroad in Italy in 1971, and she was one of the pioneers. She was dependent on door openers in Norway and abroad. The door openers role, in making professional football possible; how the professional contracts came through; and why the Scandinavian female footballers went global in the early phases, discussed. To study this the Norwegian Mother of Women’s football, Målfrid Kuvås, and other female pioneer footballers are in-depth interviewed. Kuvås’ large collection of scrapbooks with media coverage, letters and other correspondence from the 1960s to 2000s are also studied. Qualitative in-depth interviews carried out, with five of the early professionals and five of the leaders involved in the migration processes. Secondary sources are academic literature and sport media. The dream about playing professional football, and to be able to live from football brought female players across the globe. Due to this, migration research is of interest when studying women’s football, and ‘push’- and ‘pull’- factors in migration are discussed.     

A fluid dynamic investigation of the Big Blade and Macon oar blade designs in rowing propulsion

Abstract

The purpose of this investigation was to examine the fluid dynamic characteristics of the two most commonly used oar blades: the Big Blade and the Macon. Scaled models of each blade, as well as a flat Big Blade, were tested in a water flume using a quasi-static method similar to that used in swimming and kayaking research. Measurement of the normal and tangential blade forces enabled lift and drag forces generated by the oar blades to be calculated over the full range of sweep angles observed during a rowing stroke. Lift and drag force coefficients were then calculated and compared between blades. The results showed that the Big Blade and Macon oar blades exhibited very similar characteristics. Hydraulic blade efficiency was not therefore found to be the reason for claims that the Big Blade could elicit a 2% improvement in performance over the Macon. The Big Blade was also shown to have similar characteristics to the flat plate when the angle of attack was below 90°, despite significant increases in the lift coefficient when the angle of attack increased above 90°. This result suggests that the Big Blade design may not be completely optimized over the whole stroke.     

弯道滑行支撑腿蹬伸技术与重心移动方式之间的关系

运用运动生物力学研究方法,对优秀速滑运动员的弯道蹬伸技术与重心移动方式之间的关系进行分析,认为左右腿蹬伸方式上的不同,决定了速滑运动员在蹬冰过程中重心沿切线方向上前移程度的差异。     

对我国优秀男子跳远运动员不同的技术类型及成绩的相关研究

为探求水平速度和垂直速度之间配比关系对跳远成绩的影响,本课题采用高速 摄影和影片解析,分析、研究了９４年全国田径精英赛、田径锦标赛、田径冠军赛的 １５名运动员的有效试跳,以求获得水平速度和垂直速度之间合理的配比关系,并将 运动员分为水平型、垂直型和均衡型３类,制定出分类标准,得出最后两步水平速度 与起跳瞬时垂直速度的比值,找出３种类型与成绩的关系及表现出来的技术特征,为 今后的跳远训练提供参考。     

Effect of the racket mass and the rate of strokes on kinematics and kinetics in the table tennis topspin backhand

The purpose of this study was to investigate the effect of the racket mass and the rate of strokes on the kinematics and kinetics of the trunk and the racket arm in the table tennis topspin backhand. Eight male Division I collegiate table tennis players hit topspin backhands against topspin balls projected at 75 balls · min^?1 and 35 balls · min^?1 using three rackets varying in mass of 153.5, 176 and 201.5 g. A motion capture system was used to obtain trunk and racket arm motion data. The joint torques of the racket arm were determined using inverse dynamics. The racket mass did not significantly affect all the trunk and racket arm kinematics and kinetics examined except for the wrist dorsiflexion torque, which was significantly larger for the large mass racket than for the small mass racket. The racket speed at impact was significantly lower for the high ball frequency than for the low ball frequency. This was probably because pelvis and upper trunk axial rotations tended to be more restricted for the high ball frequency. The result highlights one of the advantages of playing close to the table and making the rally speed fast.     

业余体校举重教练员与运动员沟通行为的探析

运用文献资料、问卷调查等方法对业余体校举重教练员与运动员之间的沟通方式方法及影响因素进行分析和研究,发现教练员与运动员之间的沟通在举重训练和比赛中占有极其重要的地位,教练员与运动员的沟通有助于教练员与运动员关系融洽和训练科学化,对运动员训练成绩的提高有着不可低估的作用。     

优秀男子标枪运动员助跑速度与投掷成绩关系的研究

该研究使用运动测速雷达仪,结合高速电影摄影,对我国优秀男子标枪运动员的投掷技术进行了比赛现场测试,获得了大量有用的曲线与数据。整理分析后,揭示出优秀运动员助跑速度的变化及其与投掷成绩的关系。为今后掷标枪枝术的理论和教学训练实践,提供了较有价值的理论参考。     

Contribution of hand and foot force to take-off velocity for the kick-start in competitive swimming

This study examines the hand and foot reaction force recorded independently while performing the kick-start technique. Eleven male competitive swimmers performed three trials for the kick-start with maximum effort. Three force platforms (main block, backplate and handgrip) were used to measure reaction forces during starting motion. Force impulses from the hands, front foot and rearfoot were calculated via time integration. During the kick-start, the vertical impulse from the front foot was significantly higher than that from the rearfoot and the horizontal impulse from the rearfoot was significantly higher than that from the front foot. The force impulse from the front foot was dominant for generating vertical take-off velocity and the force impulse from the rearfoot was dominant for horizontal take-off velocity. The kick-start’s shorter block time in comparison to prior measurements of the grab start was explained by the development of horizontal reaction force from the hands and the rearfoot at the beginning of the starting motion.     

试论不同年龄阶段与休闲活动的相关性

人类经历儿童期、青少年期、成年期及老年期等不同既相关联而又各不同的年龄阶段,每个年龄阶段会因个人的成长与外在环境的改变,不仅有各个时期的主体活动,而且有其相关联的休闲活动.文章试图从人类年龄、生理、心理发展的特点探讨与之相关联的休闲活动.     

论足球运动的技战术关系

通过对足球运动技术与战术的辩证、主次、相辅、依赖、质量互变等关系的分析探讨,从多角度进一步认识足球运动技术与战术的关系,为实践活动提供理论支持。     

骨龄与生长发育的关系研究

生长发育过程中,生活年龄和生物年龄往往存在不一致,如何找到一种即方便又准确的方法,正确判断孩子的生长发育阶段,对于学校和家庭提前做好青春期教育具有重要的作用。骨龄就是一种评估生长发育状况的相对简便且准确的方法。通过文献资料法,就骨龄的测试、评定和应用等进行具体阐述。今后骨龄的评价将主要用于儿童生长发育类型的评价以及预测未来成年身高和月经初潮的年龄。     

影响高校师生关系的因素研究

高等院校担负着培养具有现代意识和创新意识的社会主义现代化建设接班人的重任,高等院校师生关系是高校诸多关系中最重要的关系,高校教师和学生之间应构建一种和谐、民主、平等的新型社会主义师生关系。然而,当前我国高校师生关系的现状却不尽如人意。文章就对影响我国高校师生关系的因素进行了深入的分析和研究,这些问题的成因主要有社会、学校、教师、学生四个方面的因素。希望我们这些教育工作者为创建和谐的高校师生关系而努力。     

冬季体育教学中和谐师生关系的构建

高校冬季体育教学中,体育教师与学生之间和谐关系的建立是实现人文教育、和谐教育与素质教育的先决条件,关系到高校教育目标完成的质量。认为体育教学的指导思想,体育教学的内容特点,体育运动的规律,教师的个人素质,学生对于教师的认识是影响冬季体育教学师生关系的主要因素。提出在冬季体育教学中应转变观念,树立正确的学生观;与学生深入交流,寻找共同语言;尊重学生,公平对待;改进教学策略,实现多元化教学;建立完善的学生发展评价机制等措施积极构建和谐的师生关系。     

湖北省男子中级后期部分体操运动员肩关节屈伸力量发展状况的研究

本文采用ＣｙｂｅｘⅡ＋测力仪，通过对湖北省男子中级后期部分体操运动员肩关节屈伸力量测试和研究表明，肩关节两侧屈伸力量无显著性差异，具有均衡性发展特点。通过测试，建立了肩关节屈仲力量评价表。     

全方位自我保健对健康长寿关系的研究

国内外专家研究指出 :人的自然寿命应享 1 2 0岁 ,这是从细胞分裂次数与细胞分裂周期乘积计算出来的结果。但现实生活告诉我们 ,尽管人们生活的水准在日益提高 ,而享尽天年的人并不多 ,英年早逝的人却不少 ,究其原因概在于对保健意识的认知方面。养生家告诫我们 ,人生在世 ,自我保健意识不能局限于某一方面 ,而应是全方位的 ,即 :起居有常、饮食有节、摄食科学、劳逸适度、情志豁达、动静兼练 ,并要根据自己的实际情况 ,找出一条适宜自我的规律来 ,方能走上健康长寿的道路