Coaches' encouragement of athletes' imagery use

To investigate whether coaches encourage their athletes to use imagery, two studies were undertaken. In the first, 317 athletes completed the Coaches' Encouragement of Athletes' Imagery Use Questionnaire. In the second, 215 coaches completed a slightly modified version of this questionnaire. It was found that coaches and athletes generally agreed on the relative frequency with which coaches encourage athletes to use imagery across the 4 Ws (i.e., where, when, why, and what). Coaches promoted imagery use more in conjunction with competition than training and injury rehabilitation, and higher-level coaches encouraged imagery use far more than their recreational counterparts. In addition, the level of athlete being coached had a major impact on how much or little coaches encouraged their athletes to use imagery. Coaches encouraged higher level athletes (i.e., international, national, varsity) to use imagery more than club and recreational athletes.     

The effect of periodized resistance training on accelerative sprint performance

The purpose of this study was to assess the effect of periodized resistance training on accelerative sprint performance. Sixteen physically active men participated in a randomized controlled study. An experimental group (n = 10) completed an 8-week periodized resistance training intervention, while a control group (n = 6) did not train. Pre- and post-training measures of 20-m straight-line sprint time, including a 10-m split, maximum strength, and explosive strength, were recorded. Flight time, stance time, stride length, and stride frequency were quantified from digitized video recordings of the first three strides of the 20-m sprint. Resistance training resulted in significant increases in maximum strength (parallel back squat: 19%) and explosive strength (6-10%). However, both groups increased 0-10 m sprint times (experimental group = 6%; control group = 3%) while 10-20m times were reduced (experimental group = 7%; control group = 4%), highlighting the mechanical differences between the distinct sprint phases. The change during the 0-10m interval was accompanied by a reduction in stride frequency during the first three strides. Strength coaches should be aware that the potential benefits of increased muscular strength during short sprints are likely to be affected by mechanical specificity and that improvements in sprinting performance may not occur immediately after a period of resistance training.     

新媒体联盟地平线报告:2016高等教育版

未来五年高等教育机构将会面临什么形势?有哪些趋势和技术将会驱动教育的变革?有哪些挑战是我们认为可以解决或难以克服的?《新媒体联盟地平线报告:2016高等教育版》揭示了未来五年全球范围内影响高等教育变化的关键趋势、重要挑战和重要的技术发展.图1是报告的内容框架.     

职业能力导向的项目实训课程的网络教学设计与实现

以职业能力需求为导向,以网络教学平台为载体,通过远程教学设计与实践,培养符合经济社会发展需要的应用型人才是远程教育人才培养模式改革的新亮点.本文以开展网络教学难度较大的项目实训类课程为研究对象,在分析传统项目实训类课程存在弊端的基础上,结合多年网络教学实践经验,提出了与行业无缝衔接、系统化教学设计、创设仿真学习活动情景等适合远程教育实践教学的项目实训类课程网络教学策略,并在“Android平台移动云计算开发实训”实训网络课程的教学实践中得以应用,以期解决传统实训类课程长期存在的弊端,并对实训类课程如何提升网络教学质量提供借鉴.     

儿童届也有『凡尔赛』?

公园有两个小朋友,其中一个手里拿着手枪型饮料,另一个没有.没有饮料的小朋友眼巴巴地看着另一个玩,另一个男孩发现了他的羡慕,没有选择分享,而是花式炫耀玩给他看. 生活中这样的场景是不是经常会遇见?那个故意显摆的孩子真的有那么讨厌吗?实际上每个孩子在成长过程中,都不可避免有过类似炫耀的经历.     

Energy balance of locomotion with pedal-driven watercraft

In this study, we examined the mechanics and energetics of locomotion with a paddle-wheel boat and a water bike. Power output (Wtot) was measured directly on the water bike by means of an instrumented chain-ring. The simultaneous assessment of oxygen uptake (VO2) allowed the computation of the "overall" efficiency of locomotion (etao = Wtot/VO2). Mean etao was 0.27 (s = 0.02), which was unaffected by the speed, and was assumed to be the same for the two boats as both are semi-recumbent bicycles. For the paddle-wheel boat, Wtot was then obtained from etao and measures of VO2. The power to overcome (passive) drag was calculated as Wd = D x v (where D is the force measured by means of a load cell when towing the boats at given speeds). Propelling efficiency was calculated as etap = Wd/Wtot, which was lower with the paddle-wheel boat (mean 0.35, s = 0.01) than with the water bike (mean 0.57, s = 0.01). The observed differences in etap and Wd explain why at the highest speed tested (approximately 3 m s(-1), the energy required to cover a unit distance with the water bike is similar to that required to move the paddle-wheel boat at 1.3 m s-1).     

Electrical and mechanical response of skeletal muscle to electrical stimulation after acute passive stretching in humans: a combined electromyographic and mechanomyographic approach

Two mechanisms have been suggested to explain stretching-induced maximum force depression: a mechanical alteration in the stretched muscle and an impairment of neural activation. Electrical stimulation allows standardization of the level of muscle activation without being limited by neural control. The aim of this study was to evaluate the stretching-induced changes in the electrical and mechanical properties of muscle during electrically elicited contractions. Twelve participants (age 22 +/- 1 years; body mass 75 +/- 2 kg; stature 1.79 +/- 0.02 m; mean +/- standard error) underwent six electrical stimulations of the medial gastrocnemius muscle before and after stretching. During the contractions, surface electromyogram (EMG) and mechanomyogram (MMG) were recorded simultaneously together with force. After stretching we found: (i) no differences in EMG parameters; (ii) MMG amplitude decreased by 4 +/- 1% (P < 0.05); and (iii) the peak force, the peak rate of force development, and the acceleration peak of force development decreased by 12 +/- 3%, 14 +/- 1%, and 24 +/- 5%, respectively (P < 0.05). In conclusion, acute passive stretching did not change EMG properties but altered the mechanical characteristics of the contracting muscle. Indeed, muscle force-generating capacity and stiffness of the muscle-tendon unit were significantly impaired.     

Contextual influences on baseball ball-strike decisions in umpires, players, and controls

Baseball umpires, players, and control participants with no baseball experience were asked to call balls and strikes for video clips. In a basic judgement task, umpires and players were significantly better at calling pitches than controls. In a direct information task, borderline pitches were presented following clips of definite balls and definite strikes. Participants called target pitches closer to the strike end of the scale when viewed after definite balls than when they followed definite strikes. Similarly, when borderline pitches were shown in different pitch counts, participants called pitches more towards the strike end of the scale when there were three balls in the count (3-0, 3-2). These findings indicate that the standard for evaluation changes based on the context in which stimuli are processed. Moreover, the strength of the contextual factors is illustrated in that the effects were shown in observers with and without experience in the task. Overall, however, umpires had a greater tendency to call strikes, indicating that they may use a norm of "hastening the game".     

On the temporal and behavioural consistency of pre-performance routines: an intra-individual analysis of elite basketball players' free throw shooting accuracy

The effectiveness of pre-performance routines on skilled performance in a self-paced skill has yet to be verified. In this study, we examine the importance of temporal and behavioural consistency in these routines. The duration and specific pattern of behaviours exhibited before each free throw (n = 284) were observed during 14 National Basketball Association play-off games. An intra-individual standardized score was calculated for each shot's duration. Each player's dominant behavioural routine was identified and each shot was classified as "sequence followed" or "sequence not followed". No difference was observed in the success rates of shots associated with brief, long, and regular duration routines (P > 0.05). However, players were more successful when they followed their dominant behavioural sequence (83.77% success) than when they deviated from their specific behavioural pattern (71.43% success) (P < 0.05). The findings are interpreted in light of relevant theory and implications for practice are discussed.