中外优秀男排选手前排扣球技术的三维运动学比较研究

通过三维高速录像研究表明 ,中国选手具有起跳时间短 ,两脚同时蹬地的起跳特征 ;外国选手具有起跳时间长 ,两脚依次蹬地的起跳特征。扣球是以转体、伸肩和收腹带动挥臂击球的三维动作 ,转体和伸肩动作占有重要作用。击球瞬间肘关节呈 15 0 (°)左右略屈肘击球能充分发挥前臂旋内加速功能。     

Accelerometer and GPS Data to Analyze Built Environments and Physical Activity

ABSTRACT

Purpose: Most built environment studies have quantified characteristics of the areas around participants’ homes. However, the environmental exposures for physical activity (PA) are spatially dynamic rather than static. Thus, merged accelerometer and global positioning system (GPS) data were utilized to estimate associations between the built environment and PA among adults. Methods: Participants (N = 142) were recruited on trails in Massachusetts and wore an accelerometer and GPS unit for 1–4 days. Two binary outcomes were created: moderate-to-vigorous PA (MVPA vs. light PA-to-sedentary); and light-to-vigorous PA (LVPA vs. sedentary). Five built environment variables were created within 50-meter buffers around GPS points: population density, street density, land use mix (LUM), greenness, and walkability index. Generalized linear mixed models were fit to examine associations between environmental variables and both outcomes, adjusting for demographic covariates. Results: Overall, in the fully adjusted models, greenness was positively associated with MVPA and LVPA (odds ratios [ORs] = 1.15, 95% confidence interval [CI] = 1.03, 1.30 and 1.25, 95% CI = 1.12, 1.41, respectively). In contrast, street density and LUM were negatively associated with MVPA (ORs = 0.69, 95% CI = 0.67, 0.71 and 0.87, 95% CI = 0.78, 0.97, respectively) and LVPA (ORs = 0.79, 95% CI = 0.77, 0.81 and 0.81, 95% CI = 0.74, 0.90, respectively). Negative associations of population density and walkability with both outcomes reached statistical significance, yet the effect sizes were small. Conclusions: Concurrent monitoring of activity with accelerometers and GPS units allowed us to investigate relationships between objectively measured built environment around GPS points and minute-by-minute PA. Negative relationships between street density and LUM and PA contrast evidence from most built environment studies in adults. However, direct comparisons should be made with caution since most previous studies have focused on spatially fixed buffers around home locations, rather than the precise locations where PA occurs.     

Development of the Exercise Motives and Gains Inventory

There are existing measures of exercise motives (what people want from exercise), but corresponding measures of gains (what people get) are needed, because motives and gains could influence each other and together influence other variables. An exercise motives and gains inventory (EMGI) was developed by creating gains scales to complement existing Exercise Motivations Inventory 2 scales. Confirmatory factor analyses of EMGI items established that items reflected their intended constructs; and that motive and gain constructs were distinct. Exploratory structural equation modeling of EMGI scales established that the higher-order structures of motives and gains were somewhat different: Appearance motive was associated with weight management, whereas appearance gain was associated with health and fitness. Paired-sample t-tests established that gains were less than motives in some instances (ill-health avoidance, positive health), and greater in others (e.g., affiliation, challenge). The EMGI can be used to investigate the consequences and causes of motives and gains.     

Book Reviews

This study examined the teaching of games via a tactical approach (also known as teaching games for understanding) from the theoretical perspective of social constructivism. A pilot study (of student teachers (STs) and pupils) informed the ‘main’ study which included collecting data on 49 STs, 58 cooperating teachers (CTs) and 1177 pupils. ST data were collected through videotaping (lessons), interviews and questionnaires; CT data through interviews and questionnaires; and pupil data through questionnaires. Data analysis techniques included systematic coding of teaching behaviours through computer software, using constant comparison to code open-ended question responses, and computing frequencies of Likert-scale question responses. T-tests were used to compare pre- and post-CT workshop data. Findings suggest that STs’ teaching of the tactical approach was in line with a social constructivist perspective, in part because lessons were student-centred. Overall student activity was 53% of all lessons taught, and STs facilitated pupil learning through several question and answer scenarios. Pupils wrote that they enjoyed playing games in what amounted to ‘authentic’ settings. Their responses also suggest that learning took place through ‘legitimate peripheral participation in communities of practice’ and this facilitated pupil movement through the ‘zone of proximal development’. There were indications that pupil experiences were mediated by ST competence. CTs reported that an in-service workshop on the tactical approach and mentoring was beneficial and subsequent pairings with STs elicited positive feelings from both parties.     

Perceived social support from team-mates: Direct and stress-buffering effects on self-confidence

Abstract

In this study, we wished to determine whether the perceived support available from team-mates predicts levels of self-confidence. Four dimensions of support were examined: emotional, esteem, informational, and tangible. The sample consisted of 152 university athletes (74 females, 78 males) with a mean age of 20.1 years (s=1.4). Participants completed measures of perceived support, stressors, and self-confidence at the training session before an important match. Moderated hierarchical regression analyses revealed that all four dimensions of support had direct effects on self-confidence (ΔR ²=0.13–0.17, all P<0.01), with support positively predicting self-confidence. Perceived emotional (ΔR ²=0.05, P<0.05), esteem (ΔR ²=0.02, P<0.05), and informational (ΔR ²=0.03, P <0.05) support also had stress-buffering effects on self-confidence. The findings suggest that although university athletes perceived different levels of emotional, esteem, informational, and tangible support to be available from their team-mates, all four dimensions of support positively predicted self-confidence.     

Match activities of top-class female soccer assistant referees in relation to the offside line

Abstract

The aim of this study was to examine the match activities of top-class female assistant referees (mean age 34.8 years, s=3.5; stature 1.64 m, s=0.05; weight 58.1 kg, s=7.4; body mass index 21.6 kg · m^–2, s=2.4) in relation to the offside line. Computerized match analyses were performed on 14 top-class assistant referees during 10 matches (a total of 20 observations) from the 2006 Fédération Internationale de Football Association (FIFA) under-20 Women's World Championship held in Russia. In addition, the position of the second last defensive player of both teams was calculated throughout the matches to determine the distance from the assistant referee to the offside line. The total distance covered during a game was 5594 m (s=473), of which 27% was sideways movements (1492 m, s=135). High-intensity activities (>13 km · h^–1) accounted for 1999 m (s=371). Mean distance from the offside line during the entire match was 1.06 m (s=0.26). Total distance covered, high-intensity activities, and distance from the offside line were not different (P>0.05) between the two halves of the game or consecutive 15-min match periods. Our results show that: (1) the kinematic demands placed on top-class female assistant referees are similar to those of top-class male assistant refereeing except for the amount of high-intensity activities, and (2) assistant referees were able to maintain the distance from the offside line during the match, which suggests an ability to keep up with the pace of the play throughout the match.     

Improving well-being through hedonic,eudaimonic, and social needs fulfillment in sport media consumption

Understanding sport consumer well-being is essential for enhancing the psychological experience and benefits of sport consumers. While watching a sporting event on TV or Internet is a key means of sport consumption, not much is known about the activity’s influence on well-being. Well-being improves when one’s hedonic, eudaimonic, and social needs are fulfilled. Need fulfillment occurs when hedonic, eudaimonic, and social values are experienced and perceived as one’s own. A pre-post survey and SEM-based research was conducted to examine individuals’ psychological experiences in sport event viewing and its link to well-being. The influences of the sport fanship and media consumption setting on the links were also examined. The results indicate that hedonic, eudaimonic, and social values experienced by sport event viewers fully or partially (moderated by sport fanship and media consumption setting) led to well-being improvement, supporting the notion of hedonic, eudaimonic, and social needs fulfillment as the mechanism of improving well-being in this context.     

从主要技术指标看我国蹦床运动的现状

本文通过对蹦床运动的完成动作时间、动作难度,完成动作减分情况等项技术指标的统计,在主要技术上对我国与世界先进水平运动员进行比较分析,剖析我国蹦床运动在目前技术上存在的主要问题,并据此提出对策和建议。     

美国体操的运作与发展因素分析

通过查阅文献资料、访问调查、数理统计等方法,分析了美国体操的具体运作情况,认为导致美国体操发展的因素主要包括两个方面:政府对体育的优惠政策、体育的商业化运作、“体教结合”的后备力量培养机制以及发达的体育传媒,它们构成了美国体操优越的外在环境;体操的历史背景、教练员机制以及体操协会的良性运作,它们成为促进美国体操发展的内部因素。     

影响都市体育文化建设因素的因子分析

以北京、广州、上海、武汉各都市的健身指导员、体育管理者为研究对象,采用文献资料法、问卷调查法、数理统计法等方法,对影响体育文化建设的相关社会学因子进行了分析。结果表明主因子有五个,分别是:管理因子、人员因子、条件因子、竞赛因子和经济因子。