The kinematic differences between accurate and inaccurate squash forehand drives for athletes of different skill levels     

Benjamin K. Williams  Ross H. Sanders  Joong Hyun Ryu  Philip Graham-Smith  Peter J. Sinclair 《Journal of sports sciences》2020,38(10):1115-1123

ABSTRACT

To maintain the accuracy of squash shots under varying conditions, such as the oncoming ball’s velocity and trajectory, players must adjust their technique. Although differences in technique between skilled and less-skilled players have been studied, it is not yet understood how players vary their technique in a functional manner to maintain accuracy under varying conditions. This study compared 3-dimensional joint and racket kinematics and their variability between accurate and inaccurate squash forehand drives of 9 highly skilled and 9 less-skilled male athletes. During inaccurate shots, less-skilled players hit the ball with a more open racket, demonstrating a difference in this task-relevant parameter. No joint kinematic differences were found for accuracy for either group. Coordinated joint rotations at the elbow and wrist both displayed a “zeroing-in” effect, whereby movement variability was reduced from the initiation of propulsive joint rotation to a higher consistency at ball-impact; potentially highlighting the “functionality” of the variability prior to the impact that enabled consistent task-relevant parameters (racket orientation and velocity) under varying conditions. Further, highly skilled players demonstrated greater consistency of task-relevant parameters at impact than less-skilled players. These findings highlight the superior ability of highly skilled players to adjust their technique to achieve consistent task-relevant parameters and a successful shot.  相似文献   

Static and dynamic accuracy of a magnetic-inertial measurement unit used to provide racket swing kinematics     

Benjamin Kane Williams  Ross H. Sanders  Joong Hyun Ryu  Pitre C. Bourdon  Philip Graham-Smith  Peter J. Sinclair 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(2):202-214

Magnetic-inertial measurement units (MIMUs) are becoming more prevalent in sports biomechanics and may be a viable tool to evaluate kinematic parameters. This study examined the accuracy of a MIMU to estimate orientation angles under static conditions and dynamically from a squash racket during a forehand drive shot. A MIMU was mounted onto a goniometer and moved through 0–90°, with static data collected at 10° increments during 10 repetitions of all three axes. Typical error analyses showed the MIMU to be very reliable (TE ≤ 0.03°). MIMU accuracy was determined via intraclass correlation coefficients (ICC) (r > 0.999, p < 0.001). An ordinary least products regression showed no proportional bias and minimal fixed bias for all axes. Dynamic accuracy was assessed by comparing MIMU and optical motion capture data of squash racket swing kinematics. A MIMU was fixed onto a racket and 10 participants each hit 10 forehand shots. Mean orientation angle error at ball impact was <0.50° and ICC showed very high correlations (r ≥ 0.988, p < 0.001) for all orientations. Swing phase root mean squared errors were ≤2.20°. These results indicate that a MIMU could be used to accurately and reliably estimate selected racket swing kinematics.  相似文献   

Understanding the majority opinion formation process in online environments: An exploratory approach to Facebook     

Sangwon Lee  Taehyun Ha  Daeho Lee  Jang Hyun Kim 《Information processing & management》2018,54(6):1115-1128

Majority opinions are often observed in the process of social interaction in online communities, but few studies have addressed this issue with empirical data. To identify an appropriate theoretical lens for explaining majority opinions in online environments, this study investigates the skewness statistic, which indicates how many “Likes” are skewed to major comments on a Facebook post; 3489 posts are gathered from the New York Times Facebook page for 100 days. Results show that time is not an influential factor for skewness increase, but the number of comments has a logarithmic relation to skewness increase. Regression models and Chow tests show that this relationship differs depending on topic contents, but majority opinions are significant in overall. These results suggest that the bandwagon effect due to social affordance can be a suitable mechanism for explaining majority opinion formation in an online environment and that majority opinions in online communities can be misperceived due to overestimation.  相似文献   

Embodied inter-referencing: encounters with and among “Asian” students in the Australian classroom     

Jane Chi Hyun Park 《Inter-Asia Cultural Studies》2019,20(2):271-289

ABSTRACT

This essay examines the pedagogical practice of referencing my experiences as a transnational Korean American woman in the classroom and considers how it opens up space for domestic and international students of East, Southeast, and South Asian backgrounds to reflect on their different identities, histories, and cultures. In particular, it focuses on how this practice enables Asian students to share their experiences of and insights about racial difference, racism, and whiteness in Australia and other parts of the world. Building on the concept of Asian “inter-referencing” from Chua Beng Huat (2015), I coin the term “embodied inter-referencing” to describe the strategic ways I use autobiographical narrative to create an inclusive, interactive, and mutually respectful learning space. I centre here on how some Asian students respond to this strategy by telling their own stories and in the process, create transnational, diasporic, and inter-Asian affective communities inside and outside the classroom.  相似文献   

Extended Validation of the Korean Version of the Quality of Life Survey     

SeYun Park  Erin Reifsteck  Diane L. Gill 《Measurement in physical education and exercise science》2019,23(2):110-117

In this study, we examined the factor structure and reliability of the Korean Quality of Life (KQoL) survey and compared the KQoL survey to both the World Health Organization Quality of Life-Brief Version (WHOQOL-BREF) and the Satisfaction with Life Scale (SWLS). We also assessed associations between KQoL scores and physical activity (PA) participation. Participants were 557 (male = 281, female = 276) healthy Korean adults with ages between 18 and 71 years (M = 33.2, SD = 14.2). Results of confirmatory factor analyses confirmed the 7-subscale model and indicated acceptable values supporting convergent validity (χ² = 1,678.758, df = 443, p < .001, RMSR = .045, RMSEA = .071, TLI = .880, CFI = .892). Correlations of KQoL subscales with similar subscales of WHOQOL-BREF and with SWLS supported concurrent validity. Results confirm that the KQoL survey can assess multidimensional aspects of quality of life (QoL), including spiritual, physical, social, and psychological. KQoL scores were positively related to PA participation, in line with previous research supporting the positive association of PA with QoL.  相似文献   

Modern dietary guidelines for healthy pregnancy; maximising maternal and foetal outcomes and limiting excessive gestational weight gain     

Kirsty Jayne Elliott-Sale  Ashley Graham  Stephanie Jane Hanley  Sherry Blumenthal  Craig Sale 《European Journal of Sport Science》2019,19(1):62-70

Abstract

Maternal dietary habits influence maternal and foetal health, representing a pathway for intervention to maximise pregnancy outcomes. Advice on energy intake is provided on a trimester basis, with no additional calories required in the first trimester and an additional 340?kcal?d^?1 and 452?kcal?d^?1 needed for the second and third trimesters. Energy intake depends on pre-gravid body mass index (BMI); underweight women are recommended an increase of 150, 200 and 300?kcal?d^?1 during the first, second and third trimester, normal weight women an increase of 0, 350 and 500?kcal?d^?1 and obese women an increase of 0, 450 and 350?kcal?day^?1. The recommendations for carbohydrate and protein intake are 175?g?d^?1 and 0.88–1.1?g?kgBM?d^?1, with no change to fat intake. The number of pre-gravid obese women is rising; therefore, we need to regulate weight in women of childbearing age and limit gestational weight gain to within the recommended ranges [overweight women 6.8–11.3?kg and obese women 5.0–9.1?kg]. This can be achieved using nutritional interventions, as dietary changes have been shown to help with gestational weight management. As pregnancy has been identified as a risk factor for the development of obesity, normal weight women should gain 11.5–16.0?kg during pregnancy. While some research has shown that dietary interventions help to regulate gestational weight gain and promote postpartum weight loss to some extent, future research is needed to provide safe and effective guidelines to maximise these effects, while benefitting maternal and foetal health.  相似文献   

Beaney,J. 2017. Creating Autism Champions / Autism Awareness Training for Key Stage 1 and 2, London: Jessica Kingsley          下载免费PDF全文

Jane Starbuck 《Support for Learning》2018,33(2):228-230

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Female Athlete Triad Coalition risk assessment tool is an evidenced-based tool that is reliable and well-described     

Mary Jane De Souza  Nancy I. Williams  Kristen J. Koltun  Nicole C. A. Strock 《Journal of sports sciences》2020,38(9):996-999

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Cultivating divergent thinking in mathematics through an open-ended approach     

Oh Nam Kwon  Jee Hyun Park  Jung Sook Park 《Asia Pacific Education Review》2006,7(1):51-61

The purpose of this study was to develop a program to help cultivate divergent thinking in mathematics based on open-ended problems and to investigate its effect. The participants were 398 seventh grade students attending middle schools in Seoul. A method of pre- and post-testing was used to measure mainly divergent thinking skills through open-ended problems. The results indicated that the treatment group students performed better than the comparison students overall on each component of divergent thinking skills, which includes fluency, flexibility, and originality. The developed program can be a useful resource for teachers to use in enhancing their students’ creative thinking skills. An open-ended approach in teaching mathematics suggested in this paper may provide a possible arena for exploring the prospects and possibilities of improving mathematical creativity.  相似文献   

碎裂QRS波联合TIMI危险评分预测急性心肌梗死患者的短期预后（英文）     

Qin-hui SHENG  Chih Chi HSU  Jian-ping LI  Tao HONG  Yong HUO 《Journal of Zhejiang University. Science. B》2018,(5)

目的:探讨碎裂QRS波(fQRS)联合心肌梗死溶栓治疗临床试验(TIMI)危险评分对急性心肌梗死(AMI)患者短期预后的评估价值。创新点:TIMI危险评分常用于AMI患者入院即刻的风险评估,TIMI评分4分的患者被评定为中危组。本研究发现,无论TIMI评分如何,出现fQRS而未行经皮冠状动脉介入治疗(PCI)的患者,其死亡率均显著升高。fQRS联合TIMI危险评分更利于AMI患者的预后评估,TIMI评分4分但同时合并fQRS的患者,可以从早期PCI介入治疗获益。方法:回顾300例AMI患者的临床资料及院内诊治经过,记录分析患者fQRS出现的时间、部位及其他临床转归,评价fQRS联合TIMI危险评分与患者临床预后的关系。结论:(1)fQRS联合TIMI危险评分可提高恶性心律失常、左室收缩功能不全(LVSD)和死亡预测的敏感度和特异度;(2)fQRS阳性的AMI患者,进行早期血运重建可降低患者心血管事件发生率,fQRS可能作为TIMI评分4分患者早期介入治疗的指征。  相似文献