足球竞赛规则(1998)摘录分析

本文通过分析认为 ,修改后的规则主要体现于促进发展、简化结构、理顺条款、严格管理等方面。     

2008年欧锦赛前场30m区域内进攻传接球配合的时空因素分析

进攻中在不同区域运用不同的配合类型,以及在同一区域运用不同的动静组合,可以更好地占有和利用时空。通过对2008年欧锦赛的数据统计分析,得出配合类型可分为7种;动态配合与区域之间具有向＂门＂性;DD、DDD和JD是主要的配合类型,且不同的配合类型有各自的战术功能。     

Experimental and finite element analysis of a tennis ball impact on a rigid surface

An explicit finite-element (FE) model of a pressurised tennis ball is presented. The FE model was used to model an oblique impact between a tennis ball and a rigid tennis surface, to further the understanding of this impact. Impacts were also conducted in the laboratory and the results from the FE model were in good agreement with this experimental data. The FE model was used to illustrate why a tennis ball rebounds with a higher vertical coefficient of restitution in an oblique impact compared to an equivalent impact perpendicular to the surface; this equivalent perpendicular impact has the same inbound velocity as the vertical component of the oblique impact. The FE model was also used to illustrate that the structural compliance of the felt covering on a tennis ball was a contributing factor to the ball attaining more spin in the impact than would have been calculated using a conventional analytical model. Also, the spin values calculated in the FE simulation were in good agreement with experimental data.     

足球裁判员受贿行为的犯罪心理学分析

主要运用多元性犯罪原因论等理论对影响足球裁判员受贿犯罪心理形成的内外在因素进行分析,为预防和矫正受贿犯罪心理提供理性参考。     

Contributions of joint rotations to ball release speed during cricket bowling: a three-dimensional kinematic analysis

The purpose of this study was to discover the contributions of individual upper body segmental rotations to ball release speed for cricket bowling and determine whether attempting to forcefully flex the lower trunk leads to an increase in ball release speed and bowling accuracy. Three dimensional kinematic data of eight male fast bowlers were recorded by a Vicon motion capture system under three cricket bowling conditions: (1) participants bowled at their stock delivery speeds (sub-max condition), (2) participants bowled at their absolute maximal speeds (max condition), and (3) participants bowled at their absolute maximal speeds but forced to flex the lower trunk (max-trunk condition). The accuracy of each delivery was also measured. The results showed that the average ball release speeds for the max-trunk condition were faster than the other two conditions. A general pattern of proximal to distal sequencing was observed for all three conditions. There was a slight decrement in accuracy seen in the max-trunk condition with respect to the other two conditions. For all three conditions, the upper arm rotation made the largest contribution, followed in turn by torso and thorax rotation, pelvis rotation, linear velocity of pelvis, and forearm and hand rotation.     

Effect of type 3 (oversize) tennis ball on serve performance and upper extremity muscle activity

This study investigated the effect of the larger diameter (Type 3) tennis ball on performance and muscle activation in the serve. Sixteen male advanced tennis players performed serves using regular size and Type 3 tennis balls. Ball speed, surface electromyography, and serve accuracy were measured. There were no significant differences in mean initial serve speeds between balls, but accuracy was significantly greater (19.3%) with the Type 3 ball than with the regular ball. A consistent temporal sequence of muscle activation and significant differences in mean activation of different muscles were observed. However, ball type had no effect on mean arm muscle activation. These data, combined with a previous study, suggest that play with the larger ball is not likely to increase the risk of overuse injury, but serving accuracy may increase compared to play with the regular ball.     

The importance and development of ball control and (self-reported) self-regulatory skills in basketball players for different positions

This study first investigated the importance of ball control and (self-reported) self-regulatory skills in achieving the elite level in basketball. The second aim was to gain insight into the development of, and association between ball control and (self-reported) self-regulatory skills that contribute to achieving the elite level, with taking into account positional differences. Talented male players (N = 73; age 16.56 ± 1.96) completed the STARtest to measure ball control and a questionnaire to measure (self-reported) self-regulation from 2008–2012. Results showed that (self-reported) reflective skills were most important to achieve the elite level (OR = 11.76; P < 0.05). There was no significant improvement in (self-reported) reflection over time for guards, forwards, and centers. Improvement in ball control was evident for guards (r = ?0.65; P < 0.05). Furthermore, guards and forwards had better ball control compared to centers (P < 0.01). For those two positions, negative correlations were found between (self-reported) reflection and ball control, i.e., higher reflection was related to better ball control (guards r = ?0.19; forwards r = ?0.18) in contrast to centers (r = 0.34). It is concluded that (self-reported) reflective skills are important to achieve the elite level, while ball control seems especially important for guards.     

Somatotyping using 3D anthropometry: a cluster analysis

Abstract

Somatotyping is the quantification of human body shape, independent of body size. Hitherto, somatotyping (including the most popular method, the Heath-Carter system) has been based on subjective visual ratings, sometimes supported by surface anthropometry. This study used data derived from three-dimensional (3D) whole-body scans as inputs for cluster analysis to objectively derive clusters of similar body shapes. Twenty-nine dimensions normalised for body size were measured on a purposive sample of 301 adults aged 17–56 years who had been scanned using a Vitus Smart laser scanner. K-means Cluster Analysis with v-fold cross-validation was used to determine shape clusters. Three male and three female clusters emerged, and were visualised using those scans closest to the cluster centroid and a caricature defined by doubling the difference between the average scan and the cluster centroid. The male clusters were decidedly endomorphic (high fatness), ectomorphic (high linearity), and endo-mesomorphic (a mixture of fatness and muscularity). The female clusters were clearly endomorphic, ectomorphic, and the ecto-mesomorphic (a mixture of linearity and muscularity). An objective shape quantification procedure combining 3D scanning and cluster analysis yielded shape clusters strikingly similar to traditional somatotyping.     

第15届世界杯男子足球决赛阶段攻入对方罚球区附近30m区域传接球失误原因的调查研究

通过对第１５届世界杯足球决赛阶段中１９队３８场次比赛的统计分析，了解到男足队员在攻入对方罚球区附近３０ｍ区域内的进攻失误中传球失误是造成进攻失败的主要原因，接停球失误的主要原因是接停球过大。     

女子乒乓球运动员横拍反手生胶的接发球技术

对4名现役优秀女子横拍反手生胶打法运动员接发球技术进行统计分析,结果显示:4名运动员反手接发球的比例高达93.2%～100%,其命中率高达82.9%～98.0%,但其直接得失分率都很低,分别为0～7.3%和2.0%～17.1%.在处理台内球的技术应用中,弹击技术的使用率均为零,接发球落点位置50%以上都在对方反手位,落点在对方正手位的比例均为零.因此,这几名运动员反手接发球使用率高,侧身正手接发球使用率却很低.反手接发球失误少,但很难直接得分.     

An impact analysis of a flexible bat using an iterative solver.

Although technology has now infiltrated and prompted evolution in most mass participation sports, the advances in bat technology in such sports as baseball and cricket have been relatively minor. In this study, we used a simple finite element modelling approach to try to shed new light upon the underlying mechanics of the bat-ball impact, with a view to the future optimization of bat design. The analysis of a flexible bat showed that the point of impact that produced the maximum post-impact ball velocity was a function of the bat's vibrational properties and was not necessarily at the centre of percussion. The details of the analysis agreed well with traditional Hertzian impact theory, and broadly with empirical data. An inspection of the relative modal contributions to the deformations during impact also showed that the position of the node of the first flexure mode was important. In conclusion, considerable importance should be attached to the bat's vibrational properties in future design and analysis.     

Lumbar spinal loading during bowling in cricket: a kinetic analysis using a musculoskeletal modelling approach

The objective of the study was to evaluate two types of cricket bowling techniques by comparing the lumbar spinal loading using a musculoskeletal modelling approach. Three-dimensional kinematic data were recorded by a Vicon motion capture system under two cricket bowling conditions: (1) participants bowled at their absolute maximal speeds (max condition), and (2) participants bowled at their absolute maximal speeds while simultaneously forcing their navel down towards their thighs starting just prior to ball release (max-trunk condition). A three-dimensional musculoskeletal model comprised of the pelvis, sacrum, lumbar vertebrae and torso segments, which enabled the motion of the individual lumbar vertebrae in the sagittal, frontal and coronal planes to be actuated by 210 muscle-tendon units, was used to simulate spinal loading based on the recorded kinematic data. The maximal lumbar spine compressive force is 4.89 ± 0.88BW for the max condition and 4.58 ± 0.54BW for the max-trunk condition. Results showed that there was no significant difference between the two techniques in trunk moments and lumbar spine forces. This indicates that the max-trunk technique may not increase lower back injury risks. The method proposed in this study could be served as a tool to evaluate lower back injury risks for cricket bowling as well as other throwing activities.     

Assessment of muscle fatigue after an ultra-endurance triathlon using tensiomyography (TMG)

In this study, we used tensiomyography (TMG) to assess muscle status immediately after an ultra-endurance triathlon. Maximal radial displacement or deformation of the muscle belly, contraction time, delay time, sustain time, and relaxation time were measured for both legs, and dependent t-tests were used to compare means between the beginning and end of the race. The 19 men assessed (age 37.9 ± 7.1 years; height 177.5 ± 4.6 cm; weight: 73.6 ± 6.5 kg) participated in the 2009 edition of the Lanzarote Ironman. Deterioration in the neural response was observed for contraction time (P = 0.008) and relaxation time (P = 0.011), with a moderate decrease in the response time (sustain time) and a loss in muscle stiffness (deformation of the muscle belly). The effect of muscle fatigue on the rectus femoris and biceps femoris was different. Barely any changes in contraction time, relaxation time, sustain time, and deformation of the muscle belly were observed, while only the contraction response time decreased to a significant extent (reduction in delay time; P = 0.003). The considerable loss in contractile capacity induced by a long-distance race was reflected in changes in the neuromuscular response and fluctuations in the contractile capacity of the muscle. These modifications, derived from a prolonged, exhausting effort, can be assessed in a simple, non-aggressive, non-invasive way using tensiomyography.     

英国青少年体育战略(2018—2022)研究及启示——基于YST战略分析

从英国青少年体育(2018—2022)战略的背景与发展、目标内容及挑战机遇三个方面深入分析。研究发现:YST青少年体育战略聚焦6个目标领域进行展开,依据英国本土环境,提出了具有针对性的青少年体育促进战略,结合身体活动带来的健康益处主要从“个人、学校、社会”等层面提出战略优化路径;把体育素养作为国家战略融入学校体育课程体系,全面促进青少年体育发展。得出对我国青少年体育发展的战略启示:1)以国家治理为战略主导,构建协同的青少年体育治理机制;2)以家长引领为战略基础,加强青少年体育素养教育;3)以学校实施为战略主体,联合社区、家庭协调共同推动;4)以体育品牌为战略关键,构建青少年体育品牌发展计划。     

Non-exercise estimation of VO(2)max using the International Physical Activity Questionnaire

Non-exercise equations developed from self-reported physical activity can estimate maximal oxygen uptake (VO(2)max) as well as submaximal exercise testing. The International Physical Activity Questionnaire (IPAQ) is the most widely used and validated self-report measure of physical activity. This study aimed to develop and test a VO(2)max estimation equation derived from the IPAQ-Short Form (IPAQ-S). College-aged males and females (n = 80) completed the IPAQ-S and performed a maximal exercise test. The estimation equation was created with multivariate regression in a gender-balanced subsample of participants, equally representing five levels of fitness (n = 50) and validated in the remaining participants (n = 30). The resulting equation explained 43% of the variance in measured VO(2)max (SEE = 5.45 ml·kg(-1)·min(-1)). Estimated VO(2)max for 87% of individuals fell within acceptable limits of error observed with submaximal exercise testing (20% error). The IPAQ-S can be used to successfully estimate VO(2)max as well as submaximal exercise tests. Development of other population-specific estimation equations is warranted.     

Bioimpedance patterns and bioelectrical impedance vector analysis (BIVA) of road cyclists

Bioelectrical impedance vector-analysis (BIVA) describes cell-mass, cell function and hydration status of an individual or a group. The goal of the present investigation was to provide bioelectrical impedance data for 525 male road cyclists (155 professionals, 79 elite, 59 elite-youth, and 232 amateurs) at the time of their optimal performance level. Data were plotted on the resistance-reactance (R-Xc) graph to characterize cyclists group vectors using BIVA. Compared to the general male population, the mean vector position of the road cyclists indicates a higher body cell mass (BCM) and phase angle (p<0.001). The vector position of the high-performance, compared to the amateur cyclists showed similar patterns with higher BCM and phase angles and higher reactance values for the high-performance athletes (p<0.001). The bio-impedance data were used to calculate the 50%, 75%, and 95% tolerance ellipses of each group of cyclists. The characteristic vector positions of the road cyclists indicate normal hydration and greater muscle mass and function of the high-performance cyclists compared to amateur cyclists and the normal population. The cyclists specific tolerance ellipses, particularly the high-performance cyclists might be used for classifying a cyclist according to the individual vector position and to define target vector regions for lower level cyclists.     

Concurrent criterion validity of a novel portable motion analysis system for assessing the landing error scoring system (LESS) test

The landing error scoring system (LESS) assesses the quality of a landing after a jump. The quality of the jump is usually evaluated using a three-dimensional (3-D) motion analysis system or a two-dimensional (2-D) video analysis visually rated by a clinician. However, both methods have disadvantages. The aim of this study was to examine the concurrent validity of a novel portable motion analysis system (‘PhysiMax System’) in assessing the LESS score by comparing it to video analysis. The study population included 48 healthy participants (28.45 ± 5.61 years), each performing the LESS test while two video cameras and the ‘PhysiMax’ simultaneously recorded the jump. The ‘Physimax’ system automatically evaluated the LESS. Subsequently, the examiners scored the test by viewing the video recordings, blinded to the ‘PhysiMax’ results. The mean LESS score, using the video recordings and the ‘PhysiMax’ was 4.77 (±2.29) and 5.15 (±2.58), respectively, (ICC = 0.80, 95% confidence intervals 0.65–0.87), mean absolute differences 1.13 (95% confidence intervals; 0.79–1.46). The results indicate a high consensus between the methods of measurement. The ‘Physimax’ system’s main advantages are portability, objective evaluation and immediate availability of results. The system can be used by athletic trainers and physiotherapists in the clinic and in the field for jumping assessment.     

Methodological considerations for researchers and practitioners using pedometers to measure physical (ambulatory) activity

Researchers and practitioners require guidelines for using electronic pedometers to objectively quantify physical activity (specifically ambulatory activity) for research and surveillance as well as clinical and program applications. Methodological considerations include choice of metric and length of monitoring frame as well as different data recording and collection procedures. A systematic review of 32 empirical studies suggests we can expect 12,000-16,000 steps/day for 8-10-year-old children (lower for girls than boys); 7,000-13,000 steps/day for relatively healthy, younger adults (lower for women than men); 6,000-8,500 steps/day for healthy older adults; and 3,500-5,500 steps/day for individuals living with disabilities and chronic illnesses. These preliminary recommendations should be modified and refined, as evidence and experience using pedometers accumulates.     

运动对脂蛋白(a)的影响

脂蛋白(a)[LP(a)] 在结构上类似低密度脂蛋白(LDL) 。血清中Lp(a) 浓度基本上受遗传决定,但有种族差异。Lp(a) 与心血管疾病之间联系有明显的独立性。冠心病是世界许多发达国家中引起死亡的主要因素,运动是预防冠心病的重要手段之一。因此近年来人们开始注意各种运动训练对Lp(a) 浓度的影响,以期探讨运动防治冠心病之机理。结果表明,长期耐力训练可轻度升高Lp(a) 浓度。初步推测,这种运动可能较有利于运动引起的血管微小创伤的修复,与其他血浆脂蛋白的变化一起对防治冠心病(CHD) 有积极作用。急性大强度运动后,可使受试者血Lp(a)浓度下降,表现出组织损伤之应激反应。     

Confirmatory factor analysis of the Purchaser Style Inventory for Sport Products (PSISP)

Consumers are bombarded every day by numerous promotion messages, and their decision making in purchasing sport goods or services is frequently confused by these advertised information (Lysonski, Durvasula, & Zotos, 1996). For this reason, research in consumer decision-making styles has become increasingly popular. In 2009, Bae, Lam, and Jackson developed the Purchaser Style Inventory for Sport Products (PSISP) to identify consumers’ shopping behaviors. However, the PSISP was exploratory in nature. The purpose of this study was to validate the PSISP using confirmatory factor analysis. Participants (N = 455) were college students in the southern region of the United States. Fit indices (e.g., CFI = .92, SRMR = .068, RMSEA = .065: 90% CI = .062; .068) indicated the model provided reasonable fit to the data. After model respecification, the 37-item PSISP-II model significantly (p < .001) improved and included nine latent factors: Quality, Brand, Fashion, Recreation, Price, Impulse, Confusion, Habit, and Endorsement. It was concluded that the PSISP-II was a reliable scale in measuring consumer decision-making styles in purchasing sport products.