轮滑运动员竞赛失利的心理因素分析及对策研究

随着轮滑运动的水平不断提升,各种高、难、险的新技术的更新利用,使这个原本就有很繁杂技术的竞技项目增加了许多意外因素,再加上比赛中激烈的竞争刺激,必然会导致由于心理因素的影响而产生比赛失败的现象。通过文献分析法、调查访问法、心理问卷法和数理统计法,对影响比赛失利的心理因素的种类、特点和原因进行了分析,研究结果表明：失败心理与性格关系、场依存性特征有着密切的关系。据此,从体育心理学的角度提出了相应的解决对策。     

Cardiopulmonary loading in motocross riding

Abstract

The present study was designed to examine physiological responses during motocross riding. Nine Finnish A-level motocross riders performed a 15-min ride at a motocross track and a test of maximal oxygen uptake ([Vdot]O_2max) in the laboratory. Cardiopulmonary strain was measured continuously during the ride as well as in the [Vdot]O_2max test. During the ride, mean [Vdot]O₂ was 32 ml · kg^?1 · min^?1 (s = 4), which was 71% (s = 12) of maximum, while ventilation (V _E) was 73% (s = 15) of its maximum. The relative [Vdot]O₂ and V _E values during the riding correlated with successful riding performance (r = 0.80, P < 0.01 and r = 0.79, P < 0.01, respectively). Mean heart rate was maintained at 95% (s = 7) of its maximum. Mean blood lactate concentration was 5.0 mmol · l^?1 (s = 2.0) after the ride. A reduction of 16% (P < 0.001) in maximal isometric handgrip force was observed. In conclusion, motocross causes riders great physical stress. Both aerobic and anaerobic metabolism is required for the isometric and dynamic muscle actions experienced during a ride.     

Mechanics of Batting: Effect of Stride Technique on Ground Reaction Forces and Bat Velocities

The benefits associated with being physically active are well documented, but a significant proportion of the population is insufficiently active. Physical inactivity is a major health risk factor in our society, and physical education programs are consistently identified as a means to address this concern. The purpose of this article is to use the social-ecological model as a framework to examine ways in which physical education programs can play an important role in promoting physical activity. Policies that require time allocations and resources for physical education and physical activity in schools and community designs that provide infrastructure that makes being physically active accessible and convenient are important factors in making schools and communities healthier spaces. It is clear, however, that policies alone are not sufficient to address concerns about physical inactivity. We must consider individual factors that influence decisions to be physically active in efforts to engage children in physical education programs that promote active lifestyles. The learning climate that teachers create determines what students do and learn in physical education classes. Ensuring that students see value in the content presented and structuring classes so that students believe they can experience success when they exert effort are key elements in an effective motivational climate. Efforts to address public health concerns about physical inactivity require a comprehensive approach including quality physical education. It is critical that kinesiology professionals emerge as leaders in these efforts to place physical education programs at the center of promoting children's physical activity.     

The Kinematics and Kinetics of the Running Pattern of Two-, Four-, and Six-Year-Old Children

Abstract

Selected kinematic and kinetic variables in the running pattern of 2-, 4-, and 6-year-old children were investigated. Cinematographic records and force-plate tracings were used to study the running patterns of the 28 Caucasian subjects, 15 male and 13 female. A 2 × 3 (sex × age) factorial analysis of variance was used to determine whether effects of variation between and within age and sex factors for each of the dependent variables of selected kinematic (displacement and velocity) and kinetic (ground reaction force) variables were significant. The running speeds improved with age. Although height and weight gains influenced the improvement shown in performance, certain biomechanical variables also contributed to the development of the running pattern. In the majority of the selected kinematic and kinetic variables there were significant differences between the 2-year-old group and the other two groups. Where there were significant differences in the variables, the differences tended to be in displacement, velocity, and magnitude of force measures, rather than in time of occurrence measures. Significant differences between male and female subjects appeared in five kinematic variables related to the swing leg.     

我国公共体育场地的现状研究

运用文献资料、数理统计、专家访谈和逻辑分析等研究方法,根据第五次全国体育场地普查数据资料,从场地类型、分布状况、隶属关系、经济成分、投资方式、场地使用率等方面对我国公共体育场地的现状进行分析。     

Hammer acceleration due to thrower and hammer movement patterns

Ground reaction force and wire tensile force were measured during test throws by three hammer throwers: the Asian record holder, who had a personal best of 83.47 m at the time of the investigation, and two university athletes, with personal bests of 59.95 m and 46.30 m respectively. They were filmed using three high-speed video cameras (250 Hz). The displacements of the hammer head and the athletes' centres of mass were calculated using three-dimensional analysis procedures. The Asian record holder's centre of mass and the hammer head on the final two turns exhibited approximate conjunctions of the hammer high point and the thrower's low point and vice versa about the hammer's azimuth angle. It is conjectured that the reason why the thrower's movement is asynchronous with the hammer's movement by approximately half a turn is to accelerate the hammer head in a manner similar to the way that the amplitude of a pendulum increases when it is pulled upward by a string against the downward movement of the swinging weight.     

低速带电粒子在均匀电磁场中的运动轨迹

系统地介绍了低速带电粒子在电磁场中的运动规律,并由此分析对此类问题的解决方法,从而加深对此内容的理解.     

地源热泵在顺德地区应用的可行性分析

根据顺德地区自然气候环境、土壤温度状况,对多种不同的热泵系统的节能、技术性和经济性参数进行了比较和分析,证明地源热泵具有节能、环保的优点,在顺德地区具有广阔的发展前景.     

Bridging western and First Nations thought: Balanced education in Whitehead's philosophy of organism and the sacred circle

The sacred circle offers a perspective for interpreting and theorizing about human development valuable in shaping the education of First Nations and non-First Nations students. For those of us in a western materialist culture who are interested in coming to understand what the sacred circle might offer, it is necessary to address assumptions in our own culture. This paper proceeds in four parts to facilitate such an understanding. Part One formulates the importance of a culturally self-critical approach to understanding education based in the sacred circle. Part Two presents the sacred circle as a pattern used to interpret meaning in First Nations education. Part Three examinesinterconnectedness through (a) whitehead's criticism of western scientific epistemology and his idea of education for balanced development, and (b) through the creator, mother earth and the Four Directions reflected in the sacred circle. Part Four interprets aholistic apprehension approach to education based in (a) Whitehead's notion's of intuition and imagination for balanced development from the sacred circle perspective, and (b) through the sacred circle in the vision quest ceremony.     

Design optimization on the front wheel orientation parameters of a vehicle

1. Introduction In order to improve the driving operation performance, the front suspension of a vehicle is generally of McPherson independent style, which can simplify the structure, lighten the unsprung mass, and conveniently arrange the engine and steering system. Moreover, it can adapt to many types of springs and is of advantage to adjust the height of the vehicle. In such a system, the axis of the kingpin is the line between the upper damper end and the intersection of the transverse ar…