挑选运动员在最合适的运动项目上

在人体中至少有七个遗传的因素影响着运动员的运动能力如:身高、体重、四肢长度、肌肉长度、肌腱附着点,肌纤维类型以及脂肪的百分比。这些遗传因素中的每一个因素与运动成绩的联系都很密切。身高身高常常是选择运动项目的一个主要决定因素。例如,大多数成功的篮球、排球和美式足球运动员其身高都是在人的平均身高之上;相反,在体操、跳水和摔跤项目上的许多运动员却是处在平均身高之下。通常在田径项目中,大多数跳高运动员的身材是比较高的,而大多数长跑运动员则相对较矮。     

谈谈与死亡相关联的中老年健康教育

以科学的态度对待死亡并进行中老年健康教育,是一个不曾被人们关注过的话题,本文将死亡与健康教育结合起来,针对中老年人的情况展开讨论,提出如何树立正确的生命价值观和死亡意识、并科学地了解死亡过程,进而积极主动地对待死亡选择,直至乐观地面对死亡体验。     

建构观下的“自主探究学习”数学教学模式

课堂教学是学校教学中最常用的一种师生互动活动,传统的课堂教学多是五个固定的教学环节:复习旧课—导入新课—讲授新课—巩固练习—布置作业,这种传统的教学模式虽然对学生知识的掌握有一定的优势,但也存在着明显的弊端.这些问题的存在和由此导致的结果迫切要求我们进行教育教学改革,而教育教学改革需要有先进的教学理论作为指导,才会有生命力,才能取得真正的成效.自20世纪80年代以来,随着心理学家研究的深入和多媒体计算机的飞速发展,建构主义理论愈来愈显示出其强大的生命力,其理论不仅对我们实施素质教育、构建新的数学教学模式有着重要…     

Dynamics of the basketball shot with application to the free throw

A completely general three-dimensional dynamic model is presented for the motion of basketball shots that may contact the rim, the backboard, the bridge between the rim and board, and possibly the board and the bridge simultaneously. Non-linear ordinary differential equations with six degrees of freedom describe the ball angular velocity and ball centre position. The model includes radial ball compliance and damping and contains five sub-models: purely gravitational flight, and ball-rim, ball-bridge, ball-board, and ball-bridge-board contact. Each contact sub-model has both slipping and non-slipping motions. Switching between the sub-models depends on the reaction force at, and velocity of, the contact point. Although the model can be used to study shots from any point on the court, we here use it to study the sets of free throw release angle, velocity, angular velocity, and lateral deviation angle that result in success (capture), as well as underhand free throws and those using an under-inflated ball. Free throw shots with larger backspin, lower inflation pressures, and underhand release conditions are shown to result in larger capture percentages.     

The role of effort in moderating the anxiety-performance relationship: Testing the prediction of processing efficiency theory in simulated rally driving

We tested some of the key predictions of processing efficiency theory using a simulated rally driving task. Two groups of participants were classified as either dispositionally high or low anxious based on trait anxiety scores and trained on a simulated driving task. Participants then raced individually on two similar courses under counterbalanced experimental conditions designed to manipulate the level of anxiety experienced. The effort exerted on the driving tasks was assessed though self-report (RSME), psychophysiological measures (pupil dilation) and visual gaze data. Efficiency was measured in terms of efficiency of visual processing (search rate) and driving control (variability of wheel and accelerator pedal) indices. Driving performance was measured as the time taken to complete the course. As predicted, increased anxiety had a negative effect on processing efficiency as indexed by the self-report, pupillary response and variability of gaze data. Predicted differences due to dispositional levels of anxiety were also found in the driving control and effort data. Although both groups of drivers performed worse under the threatening condition, the performance of the high trait anxious individuals was affected to a greater extent by the anxiety manipulation than the performance of the low trait anxious drivers. The findings suggest that processing efficiency theory holds promise as a theoretical framework for examining the relationship between anxiety and performance in sport.     

The relationship between peak height velocity and physical performance in youth soccer players

Longitudinal changes in height, weight and physical performance were studied in 33 Flemish male youth soccer players from the Ghent Youth Soccer Project. The players' ages at the start of the study ranged from 10.4 to 13.7 years, with a mean age of 12.2 +/- 0.7 years. Longitudinal changes were studied over a 5 year period. Peak height velocity and peak weight velocity were determined using non-smoothed polynomials. The estimations of peak height velocity, peak weight velocity and age at peak height velocity were 9.7 +/- 1.5 cm x year-1, 8.4 +/- 3.0 kg x year-1 and 13.8 +/- 0.8 years, respectively. Peak weight velocity occurred, on average, at the same age as peak height velocity. Balance, speed of limb movement, trunk strength, upper-body muscular endurance, explosive strength, running speed and agility, cardiorespiratory endurance and anaerobic capacity showed peak development at peak height velocity. A plateau in the velocity curves was observed after peak height velocity for upper-body muscular endurance, explosive strength and running speed. Flexibility exhibited peak development during the tear after peak height velocity. Trainers and coaches should be aware of the individual characteristics of the adolescent growth spurt and the training load should also be individualized at this time.     

小礼物

他从小在孤儿院长大,什么事都得努力去争取,所以他从来没空约会,妻子莎拉是他唯一约会过的女孩。莎拉已占据了他的心。当莎拉还没明白过来时,他已向莎拉求婚了。结婚宣誓之后,莎拉的父亲把新郎带到一旁,交给他一份小礼物,说:这是幸福婚姻的秘诀。年轻的新郎迫不及待地打开察看。     

优秀铅球运动员的运动学分析

这是一篇对美国几位优秀铅球运动员在比赛时技术的研究报告,本研究考察了几个关键性的投掷技术参数,同时发现了几个有趣的关于优秀铅球运动员技术的结论。前言以前,有关铅球投掷技术的研究表明,出手的速度、角度及高度是获得好成绩的几个最重要的参数。然而,这些数据大都有局限性,因为它们多是少数男运动的一次试投的结论。本研究的目的,是通过考察影响成绩的运动学参数及用四名优秀男     

炙手可热的新型职业

在当前股市,绝大部分股民没有能力去关注上市公司的运作情况,也没有精力去研究K线图、去数波浪、去埋在一大堆数据里进行证券分析,最简便也最适宜的选择便是听股评人士的股评分析.