Timescales for exploratory tactical behaviour in football small-sided games     

Angel Ric  Robert Hristovski  Bruno Gonçalves  Lorena Torres  Jaime Sampaio  Carlota Torrents 《Journal of sports sciences》2016,34(18):1723-1730

The aim of this study was to identify the dynamics of tactical behaviour emerging on different timescales in football small-sided games and to quantify short- and long-term exploratory behaviour according to the number of opponents. Two teams of four professional male footballers played small-sided games against two different teams with a variable number of opponents (3, 5 and 7). Data were collected using a combination of systematic observation and a non-differential global positioning system (15 Hz). The temporal diversity and structural flexibility of the players were determined by calculating the dynamic overlap order parameter q, entropy and trapping strength. Analysis of the exploratory dynamics revealed two different timescales, forming a different metastable landscape of action for each constraint. Fast dynamics lasted on average a few seconds and consisted of changes in tactical patterns. The long timescale corresponded to the shared tasks of offence and defence lasting tens of seconds. The players’ tactical diversity decreased with an increasing number of opponents, especially in defence. Manipulating numerical imbalance is likely to promote changes in the diversity, unpredictability and flexibility of tactical solutions. The fact that the temporally nested structure of constraints shaped the emergence of tactical behaviour provides a new rationale for practice task design. The manipulation of numerical imbalance on the timescale of a few tens of seconds, on which the exploratory behaviour of players saturates, may help coaches to optimise the exploratory efficiency of the small-sided games.  相似文献   

天启年间宫女休闲活动考          下载免费PDF全文

杨红  殷姿 《体育科研》2016,(1):85-87，92

本文主要采用历史文献法,以明宫词为主,明史及明代野史杂记为辅,考辨明代天启年间,后宫不同地位的宫女平日里的休闲活动。宫女游戏是女性体育的组成部分,笔者在大量文献中发现了些许新材料,以期填补女性体育史中的空白。  相似文献   

青少年体力活动干预新方式——体感游戏对青少年身体活动的影响分析     

袁川 《湖北体育科技》2016,(9):784-787

体感游戏作为体育运动与电子科技的结合产品,对其在青少年体力活动干预方面的研究有重要意义。研究从体力活动的促进、能量消耗、运动康复、社会价值以及心理效应等方面对体感游戏进行分析,发现体感游戏对青少年体力活动有明显促进作用,能满足其锻炼的需求,且对青少年心理健康具有积极地影响,能作为青少年体力活动干预的有效手段之一。  相似文献   

技术创新企业与风险投资介入的互动演化博弈分析     

孙伊云  袁汝华 《中国科技资源导刊 (中国信息导报)》2016,(1):80-87

为向技术创新企业提供有效的融资策略,借助演化博弈工具,构建了技术创新企业在融资过程中与风险投 资之间的博弈模型,对双方的策略选择进行了动态稳定性分析,通过对模型参数的优化调整,提出良性的演化状态, 并使用数值仿真分析,验证研究结果。研究表明,技术创新企业自身的创新能力是融资的关键,风险投资的资金投入 是企业创新的动力,而技术创新收益的合理分配则是企业从风险投资那里获得融资的保障。最后根据研究结果,基于 演化博弈模型提出相应建议。  相似文献   

Force–velocity property of leg muscles in individuals of different level of physical fitness     

Ivan Cuk  Dragan Mirkov  Aleksandar Nedeljkovic  Milos Kukolj  Dusan Ugarkovic 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(2):207-219

The present study explored the method of testing muscle mechanical properties through the linear force–velocity (F–V) relationships obtained from loaded vertical jumps. Specifically, we hypothesised that the F–V relationship parameters depicting the force, power, and velocity of the tested muscles will differ among individuals of different physical fitness. Strength trained, physically active, and sedentary male participants (N = 10 + 10 + 10; age 20–29 years) were tested on maximum countermovement and squat jumps where manipulation of external loads provided a range of F and V data. The observed F–V relationships of the tested leg muscles were approximately linear and mainly strong (median correlation coefficients ranged from 0.77 to 0.92; all p < 0.05), independently of either the tested group or the jump type. The maximum power revealed higher values in the strength trained than in the physically active and sedentary participants. This difference originated from the differences in F-intercepts, rather than from the V-intercepts. We conclude that the observed parameters could be sensitive enough to detect the differences among both the individuals of different physical fitness and various jump types. The present findings support using loaded vertical jumps and, possibly, other maximum performance multi-joint movements for the assessment of mechanical properties of active muscles.  相似文献   

Determining optimal cadence for an individual road cyclist from field data     

Robert Reed  Simon Adrian Jobson  Louis Passfield 《European Journal of Sport Science》2016,16(8):903-911

The cadence that maximises power output developed at the crank by an individual cyclist is conventionally determined using a laboratory test. The purpose of this study was two-fold: (i) to show that such a cadence, which we call the optimal cadence, can be determined using power output, heart-rate, and cadence measured in the field and (ii) to describe methodology to do so. For an individual cyclist's sessions, power output is related to cadence and the elicited heart-rate using a non-linear regression model. Optimal cadences are found for two riders (83 and 70 revolutions per minute, respectively); these cadences are similar to the riders’ preferred cadences (82–92?rpm and 65–75?rpm). Power output reduces by approximately 6% for cadences 20?rpm above or below optimum. Our methodology can be used by a rider to determine an optimal cadence without laboratory testing intervention: the rider will need to collect power output, heart-rate, and cadence measurements from training and racing sessions over an extended period (>6 months); ride at a range of cadences within those sessions; and calculate his/her optimal cadence using the methodology described or a software tool that implements it.  相似文献   

Effects of load mass carried in a backpack upon respiratory muscle fatigue     

Mark Faghy  Sam Blacker  Peter I. Brown 《European Journal of Sport Science》2016,16(8):1032-1038

Purpose: The purpose of this study was to investigate whether loads carried in a backpack, with a load mass ranging from 0 to 20?kg, causes respiratory muscle fatigue. Methods: Eight males performed four randomised load carriage (LC) trials comprising 60?min walking at 6.5?km?h^?1 wearing a backpack of either 0 (LC₀), 10 (LC₁₀), 15 (LC₁₅) or 20?kg (LC₂₀). Inspiratory (P_Imax) and expiratory (P_Emax) mouth pressures were assessed prior to and immediately following each trial. Pulmonary gas exchange, heart rate (HR), blood lactate and glucose concentration and perceptual responses were recorded during the first and final 60?s of each trial. Results: Group mean P_Imax and P_Emax were unchanged following 60-min load carriage in all conditions (p?>?.05). There was an increase over time in pulmonary gas exchange, HR and perceptions of effort relative to baseline measures during each trial (p?p?>?.05). Conclusions: These findings indicate that sub-maximal walking with no load or carrying 10, 15 or 20?kg in a backpack for up to 60?min does not cause respiratory muscle fatigue despite causing an increase in physiological, metabolic and perceptual parameters.  相似文献   

我国现有出版市场的博弈分析     

白琳 《山西师大学报(社会科学版)》2006,33(1):141-144

入世后的本土出版市场是一个充斥着理性冲突的博弈格局,政府、本土出版社与外资三方都有各自的得益要求。从博弈三方的策略分析,外资一般采取巨资涌入、内容为王、人才争夺、政策公关等策略;政府通常运用政策杠杆作为主要调控手段;本土出版机构常常是在政府与外资之间寻求可能而利益最大化的发展途径。这种合作策略的选择是典型的相互性决策,而均衡性决策才是最佳的市场选择。  相似文献   

旅游业发展中环境保护的博弈分析   总被引：1，自引：0，他引：1  

高嘉 《荆州师范学院学报》2007,30(6):97-99

在完全竞争市场经济下，博弈的纳什均衡对环境保护是不利的或低效率的。旅游开发中环境保护需要政府干预，因此，在大力发展旅游经济的同时，有关政府部门应该对旅游环境加强宏观保护和综合治理，使旅游资源能够得以持续利用，使旅游业真正成为一项“朝阳产业”。  相似文献   

创造愉悦氛围实现愉悦创造 --论教学中的智力激活     

杨新敏 《雁北师范学院学报》2002,18(3):37-39

在高等教育中，如何才能培养出高素质的创新性人才?本总结为三个方面：知识获取游戏化、个人发展兴趣化、创造潜能激发化。学习前人的知识是创新的前提，但荻取知识的过程不应成为一种苦修过程，而应遵循快乐原则，使动机游戏化。个人发展上，一要尊重学生的兴趣，二要注意发现与培养学生的兴趣，变被动学习为主动探索。  相似文献