分析比较中外短跑运动员途中跑技术的差异

通过文献资料、分析对比等方法,对短跑途中跑技术进行分析,发现我国运动员在途中跑“后蹬屈膝式”技术及放松、步幅、节奏等技术方面与国外优秀选手存在一定差距。     

Maximal lactate steady state in trained adolescent runners

The aims of this study were: (1) to identify the exercise intensity that corresponds to the maximal lactate steady state in adolescent endurance-trained runners; (2) to identify any differences between the sexes; and (3) to compare the maximal lactate steady state with commonly cited fixed blood lactate reference parameters. Sixteen boys and nine girls volunteered to participate in the study. They were first tested using a stepwise incremental treadmill protocol to establish the blood lactate profile and peak oxygen uptake ([Vdot]O₂). Running speeds corresponding to fixed whole blood lactate concentrations of 2.0, 2.5 and 4.0?mmol?·?l^?1 were calculated using linear interpolation. The maximal lactate steady state was determined from four separate 20-min constant-speed treadmill runs. The maximal lactate steady state was defined as the fastest running speed, to the nearest 0.5?km?·?h^?1, where the change in blood lactate concentration between 10 and 20?min was?<0.5?mmol?·?l^?1. Although the boys had to run faster than the girls to elicit the maximal lactate steady state (15.7 vs 14.3?km?·?h^?1, P?<0.01), once the data were expressed relative to percent peak [Vdot]O₂ (85 and 85%, respectively) and percent peak heart rate (92 and 94%, respectively), there were no differences between the sexes (P?>0.05). The running speed and percent peak [Vdot]O₂ at the maximal lactate steady state were not different to those corresponding to the fixed blood lactate concentrations of 2.0 and 2.5?mmol?·?l^?1 (P?>0.05), but were both lower than those at the 4.0?mmol?·?l^?1 concentration (P?<0.05). In conclusion, the maximal lactate steady state corresponded to a similar relative exercise intensity as that reported in adult athletes. The running speed, percent peak [Vdot]O₂ and percent peak heart rate at the maximal lactate steady state are approximated by the fixed blood lactate concentration of 2.5?mmol?·?l^?1 measured during an incremental treadmill test in boys and girls.     

Changes in locomotive rates during senior elite rugby league matches

Abstract

The aim of this study was to quantify the changes in locomotive rates across the duration of senior elite rugby league matches. A semi-automated image recognition system (ProZone 3, ProZone®, Leeds, England) was used to track the movements of 59 players from six teams during three competitive matches. The players were classified into one of four positional groups: props (n = 9), back row (n = 9), pivots (n = 14) or outside backs (n = 27). Players' movements were classified as low, high or very high intensity running and reported as locomotive rates (distance covered per minute played) for successive quarters of each match. Analysis of variance revealed that only the outside backs showed a significantly lower overall locomotive rate during the final quarter compared to the first (P < 0.05). However, locomotive rates for high and very high intensity running during the final quarter were significantly lower (P < 0.05) than the first quarter among outside backs, pivots and props despite no change in the rate of involvements in contact. On the basis of these findings, it is suggested that high and very high intensity running locomotive rates may be more affective methods of detecting fatigue during competitive matches than overall locomotive rate.     

Lower limb joint kinetics during the first stance phase in athletics sprinting: three elite athlete case studies

Abstract

This study analysed the first stance phase joint kinetics of three elite sprinters to improve the understanding of technique and investigate how individual differences in technique could influence the resulting levels of performance. Force (1000 Hz) and video (200 Hz) data were collected and resultant moments, power and work at the stance leg metatarsal-phalangeal (MTP), ankle, knee and hip joints were calculated. The MTP and ankle joints both exhibited resultant plantarflexor moments throughout stance. Whilst the ankle joint generated up to four times more energy than it absorbed, the MTP joint was primarily an energy absorber. Knee extensor resultant moments and power were produced throughout the majority of stance, and the best-performing sprinter generated double and four times the amount of knee joint energy compared to the other two sprinters. The hip joint extended throughout stance. Positive hip extensor energy was generated during early stance before energy was absorbed at the hip as the resultant moment became flexor-dominant towards toe-off. The generation of energy at the ankle appears to be of greater importance than in later phases of a sprint, whilst knee joint energy generation may be vital for early acceleration and is potentially facilitated by favourable kinematics at touchdown.     

Cardiac Dimensions in Elite Young Track Athletes

The purpose of the study was to compare young sprint and distance runners for changes in their cardiac dimensions with increased age (10–17 years) or body surface area (1–2 m²). Echocardiographic dimensions were obtained on 73 male track athletes competing in the 1983 National Age Group Track and Field Association championships. Each group of athletes was also compared with a hypothetical normal population (matched for weight and age) generated from prediction equations derived by Henry, Gardin, & Ware (1980). The cardiac dimensions examined were: Left ventricular internal diameter, left ventricular posterior wall thickness, and interventricular septum thickness. The male distance runners (n = 38) had a significantly greater increase in left ventricular posterior wall thickness and interventricular septum thickness with increasing age or increasing body surface area compared to the sprinters (n = 35) or compared to the predicted normal population. The left ventricular internal diameter was not significantly different between the groups. These results indicate that the hearts of male distance runners are undergoing a training hypertrophy whereas the hearts of sprinters are no different than hearts in a normal population. The changes in cardiac dimensions of these young athletes run counter to the generalizations stated for adult athletes: That endurance training enlarges the left ventricular internal diameter, but does not increase the left ventricular posterior wall or interventricular septum thickness.     

少年女子短跑运动员途中跑支撑时间及影响因素

运用运动学与动力学理论，对少年女子短跑和跳跃项目运动员短跑途中跑支撑时间及相关影响因素进行研究。结果表明：支撑时间和年龄不相关，而是随速度提高而缩短；影响支撑时间的因素为技术、身高、快速力量和速度。通过与世界优秀运动员支撑时间比较显示：少年女子运动员支撑时间较长，腾空／支撑时间值小，前支撑／支撑时间值大，高水平运动员与此相反。认为：缩短支撑时间、形成各种合理时间特征比例是提高最大跑速的关键；在考察支撑时间对速度影响时，还应综合考虑身体结构和身高等因素。     

SRM系统在短距离自行车专项能力测试与评定中的应用研究

应用场地SRM系统对上海自行车队重点队员6人的场地专项训练分阶段进行跟踪测试,以便筛选有效指标评价短距离自行车主要专项能力。结果表明,在短距离自行车爆发力评价中,最大功率和平均功率、最大频率和平均频率是反映运动能力的有效指标;平均功率和平均频率是反映力量耐力的有效指标;在对短距离自行车专项最大速度的评价中,最大频率和平均频率是反应运动能力的有效指标;而平均频率是反映高速耐力的有效指标。     

2013年速滑短距离世锦赛分析与备战索契冬奥会的对策

通过对2013年美国盐湖城速度滑冰短距离世锦赛成绩的统计分析,对比国内外选手的优势与不足,探寻我国短距离速滑运动员存在的主要差距、努力方向和训练重点。针对我国选手存在的问题,提出针对性的解决方案,并对备战索契冬奥会进行了展望,从明确备战目标、制定好训练与参赛计划、精心选择训练策略等方面,探讨了备战索契冬奥会的对策,以期为备战2014年索契冬奥会提供参考意见。     

县域办学:浙江省独立学院转型发展路径探析

独立学院“县域办学”是浙江省在进入经济发展新常态和高等教育普及化阶段出现的办学现象,是改革开放后继中心城市办大学、高教园区建设之后浙江省第三次高等教育布局调整的重要组成部分。基于浙江省县域经济转型发展的背景,文章分析了浙江省独立学院“县域办学”的现状特征、背景成因并提出了完善独立学院“县域办学”的路径思考。     

论多样性是职业技术教育的最大特点

职业教育必须是一种在教育层次、培养目标、办学主体、教育形式等方面提供多种选择，满足多种学习和发展需要的教育，这既是社会对职业教育的客观要求，也是职业教育的最大特点。