中外优秀男运动员百米动作速度时空结构的运动学特征

通过文献资料、高速摄像和对比分析的方法,对中外男运动员百米途中跑一个单步的步长、步时及人体重心轨迹进行研究,制定了短跑运动员所应达到的步频、步幅范围与跑速之间关系的模式表,为教练员科学训练提供了依据.     

世界优秀短跑运动员100m各分段步频、步长、平均速度变化规律的研究

利用数理统计法对世界优秀短跑运动员100m跑的各分段步频、步长等运动学指标进行评析，研究表明：世界优秀短跑运动员100m跑中长时间保持高速的途径是依靠自己的步长，而不是努力提高步频来保持；全程跑的加速节奏对全程的成绩有较大的影响；在各分段步长与步频对跑速的贡献具有显性差异。     

IEEE 1588协议分析及在网络化机载测试系统的应用

本文主要讲述发展基于1588同步协议的网络化机载测试系统需求原因,并重点针对1588同步协议进行了分析,尤其是第2版本中新提出的透明时钟模型以及透明时钟的延时处理机制。在此基础之上,针对在机载测试中可能影响同步精度的因素进行了逐一的分析,并提出了处理的方法。这些因素的考量以及处理的方案对于测试方案实施与设备的研制与定制具有一定的参考意义。     

诺贝尔科学奖跨学科师承效应定量研究

交叉学科往往是学科新的生长点,有可能产生新的科学突破,为科学带来革命性的发展。交叉科学的发展离不开大量跨学科的人才,而高水平跨学科人才的培养始于交叉学科的研究生教育。文章选取1901-2013年诺贝尔科学奖获奖者为研究对象,以是否师从诺贝尔奖得主为分组变量,从物理、化学和生理或医学三大学科内和跨学科角度对比分析师承效应的影响,凸显跨学科师承效应的作用。研究结果表明,与单纯的学科内师承效应相比,考虑跨学科师生关系的师承效应可更显著地促进未来诺贝尔科学奖获奖者的成长和成才。     

Self-report vs. kinematic screening test: prevalence,demographics, and sports biography of yips-affected golfers

The yips is considered a task-specific movement disorder. Its estimated prevalence, however, is high compared to similar neurological movement disorders, possibly resulting from previous studies’ restriction of samples based on skill level, and self-report bias. Alternatively, this high prevalence might be an indication of additional aetiologies, for example the influence of previously played racket sports. We estimated the prevalence of the putting yips across the skill range, using self-reports in one study and a screening test in a second study. We explored if previously played sports matter for the development of the yips. In study 1, yips prevalence (N = 1,306) and golfers’ sports biographies (n = 264) were examined via two online surveys, in which golfers indicated if they were yips-affected. In study 2, golfers (N = 186) putted in a standardised putting test while kinematic and performance measures were recorded. Prevalence was estimated via a kinematic threshold. Sports biographies (n = 119) were obtained via an online survey. Prevalence of currently yips-affected golfers was 22.4% in study 1 and 16.7% in study 2. In both studies, more yips-affected than unaffected golfers had experience in playing racket sports. Yips prevalence remained higher than previously estimated prevalence of other movement disorders but decreased when the whole skill range including professionals and novices was considered. Future studies should use the kinematic screening test instead of self-reports to detect the yips and further investigate the influence of previously played racket sports.     

Effects of forward trunk lean on hamstring muscle kinematics during sprinting

This study aimed to investigate the effects of forward trunk lean on hamstring muscle kinematics during sprinting. Eight male sprinters performed maximal-effort sprints in two trunk positions: forward lean and upright. A three-dimensional musculoskeletal model was used to compute the musculotendon lengths and velocity of the biceps femoris long head, semitendinosus, and semimembranosus muscles during the sprinting gait cycle. The musculotendon lengths of all the three hamstring muscles at foot strike and toe-off were significantly greater during the forward trunk lean sprint than during the upright trunk sprint. In addition, a positive peak musculotendon lengthening velocity was observed in the biceps femoris long head and semimembranosus muscles during the late stance phase, and musculotendon lengths at that instant were significantly greater during the forward trunk lean sprint than during the upright trunk sprint. The present study provides significant evidence that a potential for hamstring muscle strain injury involving forward trunk lean sprinting would exist during the stance phase. The results also indicate that the biceps femoris long head and semimembranosus muscles are stretched during forward trunk lean sprinting while contracting eccentrically in the late stance phase; thus, the elongation load on these muscles could be increased.     

功能动作模式下短跑训练实证研究

功能动作训练用于短跑中,在于优化短跑运动员的技术动作,预防运动损伤,提高核心力量和核心稳定性。文章运用文献资料法、实验法、数理统计法等研究方法,对西北师范大学体育教育专业田径专选组学生短跑技术进行了研究。结果表明：（1）经过为期三个月的教学实验,实验组和对照组的步幅、步频、100米成绩与实验前相比都有明显的提高（p<0.05）。且实验组高于对照组。（2）功能动作训练能有效的提高短跑运动员的核心力量和核心稳定性。     

Largest Silurian Vertebrate Discovered from Yunnan,China

<正>An apparent absence of Silurian fishes more than half-a-metre in length has been viewed as evidence that gnathostomes(jawed vertebrates)were restricted in size and diversity prior to the Devonian.A team led by Professor ZHU Min,Institute of Vertebrate Paleontology and Paleoanthropology(IVPP)of the Chinese Academy of Sciences has unearthed a bony fi sh with an estimated length of about 1 meter from the Silurian Kuanti Formation in Yunnan Province of southwestern China,revealing that pre-Devonian gnathostomes could attain comparatively large sizes.The study published on June 12 in the journal of Scientifi c Reports adds     

三种途径获取至关重要的“弧微分”

第一种途径是自创的,仅按极限的定义并结合使用两点间的距离公式和拉格朗日中值定理就可获得弧微分计算公式;第二种途径是经典的,需要用到定积分定义、变上限函数等等;第三种途径是高职高专教材编写者常用的,它需要先默认弦长与弧长之比的极限为1;为了按顺序编写教材,第一种途径最宜。     

Persistent Focal Behavior and Physical Activity Performance

This article examines the proclivity and performance attributes of focal students across time and activities using data from 9,345 students. Three systematic focal behavior partitions are examined: Across activities, across time, and across activities and time. A student’s performance is focal if it ends in 0 or 5 for push-ups and 0 for curl-ups. Chi-square tests confirm that individual focal outcomes and systematic focal outcomes occur more frequently than random processes would suggest. In each instance, the only cell that is less populated than random processes would suggest is the one that exhibits no systematic focal behavior and the cell that exhibits the greatest deviation from expected is the full focal cell. Focal students outperform their peers on three activities at two assessments. Students with two-systematically focal outcomes have superior performance to students with no systematic focal outcomes but inferior performance to those with three or four focal outcomes.