Immediate effects of the use of modified take-off boards on the take-off motion of the long jump during training     

Koyama H  Muraki Y  Ae M 《Sports biomechanics / International Society of Biomechanics in Sports》2006,5(2):139-153

We investigated the immediate effects of the combined use of inclined and raised flat boards on the take-off motion of the long jump. Eight male long jumpers were videotaped with two high-speed video cameras (250 Hz) set perpendicular to the runway. The athletes jumped with three modified take-off boards: upward-inclined boards of two different inclinations (2.5 and 5.0 degrees), and a raised flat board (50 mm high). The jumpers performed pre- and post-jumps using their own techniques before and after use of the boards to test their effects. The post- jump revealed significantly less reduction in the horizontal velocity during the take-off than the pre-jump, and the effectiveness of converting the velocity from horizontal to vertical increased significantly in the post-jump. The post-jump demonstrated significantly less knee flexion of the take-off leg during take-off. The reduced knee flexion and slower extension velocity of the take-off leg in the second phase of the post-jump contributed to increasing the knee extension torque in the second phase and resulted in the increases in vertical ground reaction force and vertical velocity. These results suggest that the combined use of the inclined and raised flat boards induced immediate effective changes in the kinematics and kinetics of the take-off motion and represent appropriate training tools for take-off techniques of the long jump.  相似文献   

Problems faced by a writer in communicating research findings in child development     

VAN DE WATER M 《Child development》1948,19(1-2):67-75

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运动心理技能量表的常规及信度资料     

迈克尔·莱莎  谢恩·M·默菲  杨晓春 《贵州体育科技》1992,(4)

介绍迈哈尼、戈布尔和贝根斯近来发布了关于一个专门用于运动的测验的信息。该测验是用来评估与特殊运动表现有关的心理技能的。他们编写了一个51道测题的问卷(运动心理技能量表PSIS)。该量表证明,优秀运动员、有潜力的运动员和大学生运动员在注意、焦虑控制、自信、心理准备和动机上彼此存在差异。迈哈尼近来发表了该量表的修订版。原量表被  相似文献   

生物医学述评文献检索：六个联机数据库的比较评价     

Sayers  M 李旭荣 《国外情报科学》1992,10(4):50-53

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Pathogenic Vibrio spp. in the Sea Bream, Sparus sarba     

N.Y.S.Woo  J.M.L.Ling  K.M.Lo 《中山大学学报论丛》1995,(3)

VibriosisisacommonandseriousdiseasecausedbybacterialspeciesofthegenusVibrioinalargenumberofmarinefishes.Thediseaseischaracterisedbygeneralsepticaemia,superficialskinlesionsandextensivehaemorrhages[1].Upuntilaround1980,VibrioanguillarumwastheonlyVibriospecieswhichhadbeenshowntobethecausativeagentofvibriosis.However,recentstudieshaverevealedthatseveralotherVibriospeciessuchasV.alginolyticus,V.ordalli,V.damsela,andV.salmonicchwerealsoPOtentialfishpathogens.V.alginolyticus,V.porahaemolyticusa…  相似文献   

规划与决策的信息系统与技术     

Batty  M 周智佑 《国外情报科学》1991,(3):36-41,49

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感悟、鉴赏和探究：文学作品教学的三种重要方法——关于文学作品教学的几点浅思     

周红阳． 《教学月刊》2004,(11):9-12

笔者以为，文学作品教学与非文学作品教学有许多共通之处，当以“文本”为依托、“语言”为核心、“理解”为基础、“能力”为目标，换言之，要紧扣文本，揣摩语言，理解内容，发展能力。但“以艺术形象的方式对以人为中心的社会生活的整体作审美反映”㈨是文学与其他社会科学的主要区别，可见文学的特点在于形象和审美，故文学作品的教学又必须通过对形象的感悟(体验)、鉴赏(品味)和探究(发现)等方式，以达到培养和提升学  相似文献   

Dynamics of the basketball shot with application to the free throw     

Okubo H  Hubbard M 《Journal of sports sciences》2006,24(12):1303-1314

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.  相似文献   

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

Wilson M  Smith NC  Chattington M  Ford M  Marple-Horvat DE 《Journal of sports sciences》2006,24(11):1223-1233

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.  相似文献   

The relationship between peak height velocity and physical performance in youth soccer players   总被引：1，自引：1，他引：0  

Philippaerts RM  Vaeyens R  Janssens M  Van Renterghem B  Matthys D  Craen R  Bourgois J  Vrijens J  Beunen G  Malina RM 《Journal of sports sciences》2006,24(3):221-230

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.  相似文献