Tracking club sport participation from childhood to early adulthood     

Richards R  Williams S  Poulton R  Reeder AI 《Research quarterly for exercise and sport》2007,78(5):413-419

This study examined the strength of tracking sport participation from childhood to early adulthood among the Dunedin Multidisciplinary Health and Development Study cohort. Participation in sport, dance, or gymnastics as part of a club or group (outside of school) was assessed at ages 7, 9, 15, 18, and 21 years. In addition to the traditionally used correlation coefficients, summary statistics (intraclass correlations; ICC) from random effect models and stability coefficients from generalized estimating equations (GEE) were calculated using all the longitudinal data and controlling for the influence of covariates on tracking strength. Correlation coefficients revealed statistically significant tracking of club sport participation (7-21 years) at low levels (r = .07-0.28). The ICC summary statistic (0.23) was consistent with this, while the GEE suggested moderate tracking (0.59). The results of this study suggest that encouraging sport participation during childhood and adolescence may result in a modest increase in the likelihood of participation later in life. However, the substantial movement into and out of sport participation observed here and in other studies cautions against relying solely on sport promotion among youth as a strategy to promote lifelong participation.  相似文献   

Feedback after good trials enhances learning     

Chiviacowsky S  Wulf G 《Research quarterly for exercise and sport》2007,78(2):40-47

Recent studies (Chiviacowsky & Wulf, 2002, 2005) have shown that learners prefer to receive feedback after they believe they had a "good" rather than "poor" trial. The present study followed up on this finding and examined whether learning would benefit if individuals received feedback after good relative to poor trials. Participants practiced a task that required them to throw beanbags at a target with their nondominant arm. Vision was prevented during and after the throws. All participants received knowledge of results (KR) on three trials in each 6-trial block. While one group (KR good) received KR for the three most effective trials in each block, another (KR poor) received feedback for the three least effective trials in each block. There were no group differences in practice. However the KR good group showed learning advantages on a delayed retention test (without KR). These results demonstrated that learning is facilitated if feedback is provided after good rather than poor trials. The findings are interpreted as evidence for a motivational function of feedback.  相似文献   

Effects of rest interval during high-repetition resistance training on strength, aerobic fitness, and repeated-sprint ability   总被引：1，自引：0，他引：1  

Hill-Haas S  Bishop D  Dawson B  Goodman C  Edge J 《Journal of sports sciences》2007,25(6):619-628

The effect of altering the rest period on adaptations to high-repetition resistance training is not well known. Eighteen active females were matched according to leg strength and repeated-sprint ability and randomly allocated to one of two groups. One group performed resistance training with 20-s rest intervals between sets, while the other group employed 80-s rest intervals between sets. Both groups performed the same total training volume and load. Each group trained 3 days a week for 5 weeks [15- to 20-repetition maximum (RM), 2 - 5 sets]. Repeated-sprint ability (5x6-s maximal cycle sprints), 3-RM leg press strength, and anthropometry were determined before and after each training programme. There was a greater improvement in repeated-sprint ability after training with 20-s rest intervals (12.5%) than after training with 80-s rest intervals (5.4%) (P = 0.030). In contrast, there were greater improvements in strength after training with 80-s rest intervals (45.9%) than after training with 20-s rest intervals (19.6%) (P = 0.010). There were no changes in anthropometry for either group following training. These results suggest that when training volume and load are matched, despite a smaller increase in strength, 5 weeks of training with short rest periods results in greater improvements in repeated-sprint ability than the same training with long rest periods.  相似文献   

Comparison of two Actigraph models for assessing free-living physical activity in Indian adolescents     

Corder K  Brage S  Ramachandran A  Snehalatha C  Wareham N  Ekelund U 《Journal of sports sciences》2007,25(14):1607-1611

This aim of this study was to compare the new Actigraph (GT1M) with the widely used Model 7164. Seven days of free-living physical activity were measured simultaneously using both the Model 7164 and GT1M in 30 Indian adolescents (mean age 15.8 years, s = 0.6). The GT1M was on average 9% lower per epoch than model 7164, thus a correction factor of 0.91 is suggested for comparison between the two monitors. The differences between monitors increased in magnitude with intensity of activity (P < 0.001) but remained randomly distributed (r = 0.01, P = 0.96). No significant difference was observed between monitors for time spent in moderate (P = 0.31) and vigorous (P = 0.34) physical activity when using the same epoch length. The Model 7164 classified less time as sedentary (P < 0.001) and more time as light-intensity activity (P < 0.001) than the GT1M. In conclusion, data from the GT1M can be compared with historical data using average counts per minute with a correction factor, and the two models might be comparable for assessing time spent in moderate to vigorous physical activity in children when using the same epoch length.  相似文献   

Kinetic comparison of a side-foot soccer kick between experienced and inexperienced players     

Kawamoto R  Miyagi O  Ohashi J  Fukashiro S 《Sports biomechanics / International Society of Biomechanics in Sports》2007,6(2):187-198

The aim of this study was to identify critical kinetic variables that lead to increased ball velocity during a side-foot passing kick in soccer. Seven experienced male soccer players and eight inexperienced players participated in the experiment. They were instructed to perform side-foot kicks along the ground with maximum effort with an eye on the target line. The joint angles, angular velocities, and torques of the kicking leg were determined based on the three-dimensional kinematic data. The mean ball speed of the experienced group (21.4 +/- 1.5 m/s) was significantly faster than that of the inexperienced group (16.0 +/- 1.0m/s; P < 0.001). The motions of the inexperienced players tended to be less dynamic than those of the experienced players. The most noticeable difference in the kinetics of the kick was found in the hip flexion torque throughout the back-swing phase until the leg-cocking phase. The mean peak value of the experienced group (168 +/- 20 N x or m) was significantly greater than that of the inexperienced group (94 +/- 17 N x or m; P < 0.001). To increase ball speed during a side-foot passing kick, the generation of hip-flexion torque during the earlier stage of kicking is critical.  相似文献   

体力活动与癌症生存研究的10大问题     

Kerry S. Courney  Laura Q. Rogers  Kristin L. Campbell  Jeff K. Vallance  Christine M. Friedenreich 《北京体育大学学报》2016,39(2):40-48

摘要：今天的美国有1 400万的癌症存活者,其中的很多存活者中都接受了多种治疗,包括手术、放疗、化疗、靶向治疗等。这些治疗能够延长生存时间,但同时也会带来很多急慢性的副作用,危害健康,影响生活质量。体力活动（PA）与癌症生存这一领域发展迅速,主要研究PA对癌症患者的影响。基于该领域的研究进展,提出了以下10大研究问题：1）PA能够降低癌症复发风险、和/或提高存活吗？2）PA能够影响癌症治疗决策、完成率、和/或患者对治疗的反应吗？3）癌症存活者的最佳运动处方是什么？4）静坐少动行为对癌症存活者有何影响？5）癌症存活者最有效的体力活动干预方案是什么？6）哪些癌症会影响病人对PA的反应？7）癌症存活者进行体力活动时需要注意的安全问题有哪些？8）哪些具体的癌症症状可以由PA解决？9）对于癌症晚期患者,体力活动还有何作用？10）如何将体力活动研究结果转化到临床和社区肿瘤实践中来？上述问题的回答至关重要,这不仅关系到体力活动和癌症存活这一研究领域的发展,更重要的是,能够为每年数百万新诊断为癌症的病人、正在接受癌症治疗的病人、治疗结束处于恢复中的病人或是那些正在与晚期癌症抗争的病人带来福音。  相似文献   

新媒体联盟地平线报告:2016高等教育版     

L·约翰逊  S·亚当斯·贝克尔  M·卡明斯  V·埃斯特拉达  A·弗里曼  C·霍尔  殷丙山  高茜  赵广元 《北京广播电视大学学报》2016,(2):1-20

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.  相似文献   

Authoritarianism, perceived threat and exclusionism on the eve of the Disengagement: Evidence from Gaza   总被引：1，自引：0，他引：1  

Canetti D  Halperin E  Hobfoll SE  Shapira O  Hirsch-Hoefler S 《Int J Intercult Relat》2009,33(6):463-474

Major political events such as terrorist attacks and forced relocation of citizens may have an immediate effect on attitudes towards ethnic minorities associated with these events. The psychological process that leads to political exclusionism of minority groups was examined using a field study among Israeli settlers in Gaza days prior to the Disengagement Plan adopted by the Israeli government on June 6, 2004 and enacted in August 2005. Lending credence to integrated threat theory and to theory on authoritarianism, our analyses show that the positive effect of religiosity on political exclusionism results from the two-staged mediation of authoritarianism and perceived threat. We conclude that religiosity fosters authoritarianism, which in turn tends to move people towards exclusionism both directly and through the mediation of perceived threat.  相似文献   

The role of upper torso and pelvis rotation in driving performance during the golf swing   总被引：3，自引：2，他引：1  

Myers J  Lephart S  Tsai YS  Sell T  Smoliga J  Jolly J 《Journal of sports sciences》2008,26(2):181-188

While the role of the upper torso and pelvis in driving performance is anecdotally appreciated by golf instructors, their actual biomechanical role is unclear. The aims of this study were to describe upper torso and pelvis rotation and velocity during the golf swing and determine their role in ball velocity. One hundred recreational golfers underwent a biomechanical golf swing analysis using their own driver. Upper torso and pelvic rotation and velocity, and torso-pelvic separation and velocity, were measured for each swing. Ball velocity was assessed with a golf launch monitor. Group differences (groups based on ball velocity) and moderate relationships (r > or = 0.50; P < 0.001) were observed between an increase in ball velocity and the following variables: increased torso-pelvic separation at the top of the swing, maximum torso-pelvic separation, maximum upper torso rotation velocity, upper torso rotational velocity at lead arm parallel and last 40 ms before impact, maximum torso-pelvic separation velocity and torso-pelvic separation velocity at both lead arm parallel and at the last 40 ms before impact. Torso-pelvic separation contributes to greater upper torso rotation velocity and torso-pelvic separation velocity during the downswing, ultimately contributing to greater ball velocity. Golf instructors can consider increasing ball velocity by maximizing separation between the upper torso and pelvis at the top of and initiation of the downswing.  相似文献   

Hearts in the fire, heads in the fridge: a qualitative investigation into the temporal patterning of the precompetitive psychological response in elite performers     

Mellalieu SD  Hanton S  Shearer DA 《Journal of sports sciences》2008,26(8):811-824

Retrospective perceptions and causal beliefs regarding the temporal patterning of precompetitive psychological responses were examined in 12 elite rugby union players. Composite sequence analysis resulted in a series of temporal networks to describe participants' cognitive, affective, and behavioural responses in a time-to-event paradigm. Match-related cognitions remained stable in the lead up to competition, while perceptions of physical symptoms peaked at the onset of performance. Affective responses were associated with feelings of anxiety and tension in the early temporal phases but excitement, confidence, and efficacy in team-mates directly before competition. Behavioural themes described activities associated with technical and physical preparation, familiarization with environmental conditions, and strategies to control activation states early on or directly before competition. The findings highlight the idiosyncratic and dynamic nature of the temporal patterning of precompetitive responses and the influence that perceptions of the team have upon individual preparation for performance. Implications are discussed in the context of the type and timing of intervention for developing individual and team preparatory routines.  相似文献