乒乓球运动员膝关节损伤机制研究——对3种常用步法的膝关节负荷特征分析     

周星栋  肖丹丹  郭文霞  黄习梅  张晓栋 《中国体育科技》2020,(6):62-67

目的:了解不同性别乒乓球运动员完成并步、跳步、跨步3种常用步法时膝关节的负荷特征,并探析乒乓球运动员膝关节的损伤机制。方法:对乒乓球男、女各10名运动员完成3种常用步法动作时的下肢运动学、动力学数据进行采集和处理,并运用方差分析法比较不同性别、不同技术之间的差异。结果:受试者在完成3种步法过程中,膝关节屈角大致范围在20°~60°。当地面反作用力最大时,女运动员比男运动员表现出更小的外展角(P<0.05),跳步比并步和跨步表现出更小的外展角(P<0.05);在三维受力方面,膝关节受到垂直方向上的力最大,水平向后和向左的力次之,未表现出显著的性别差异和技术差异;在三维力矩方面,膝关节受到的伸膝力矩较大,也未表现出显著的性别差异和技术差异。结论:膝关节屈曲状态下,较大的地面反作用力和膝关节外展角易导致乒乓球运动员前交叉韧带损伤,女运动员的损伤风险小于男运动员,跳步的损伤风险小于并步和跨步;水平向后和向左的力易造成乒乓球运动员软骨和半月板损伤;过大的伸膝力矩易导致乒乓球运动员髌腱末端病和髌骨软化。  相似文献   

The Choice of Response Probability in Bookmark Standard Setting: An Experimental Study     

Peter Baldwin  Melissa J. Margolis  Brian E. Clauser  Janet Mee  Marcia Winward 《Educational Measurement》2020,39(1):37-44

Evidence of the internal consistency of standard-setting judgments is a critical part of the validity argument for tests used to make classification decisions. The bookmark standard-setting procedure is a popular approach to establishing performance standards, but there is relatively little research that reflects on the internal consistency of the resulting judgments. This article presents the results of an experiment in which content experts were randomly assigned to one of two response probability conditions: .67 and .80. If the standard-setting judgments collected with the bookmark procedure are internally consistent, both conditions should produce highly similar cut scores. The results showed substantially different cut scores for the two conditions; this calls into question whether content experts can produce the type of internally consistent judgments that are required using the bookmark procedure.  相似文献   

Instruction in secondary cotaught classrooms: Three elements,two teachers,one unique approach     

Margaret P. Weiss  Wendy J. Rodgers 《Psychology in the schools》2020,57(6):959-972

Coteaching is a widely used service delivery model for students with disabilities who access the general curriculum. Instruction in cotaught classrooms is meant to be qualitatively different from instruction in solo-taught classrooms; however, this is not always the case. In this article, we describe a framework for thinking about and planning instruction in cotaught classrooms that includes evidence-based practices from special education and specially designed instruction. Examples are included and discussed.  相似文献   

The Unintentional Effects on Body Donation Programs of a Competency-Based Curriculum in Postgraduate Medical Education     

Geoffroy P.J.C. Noël  Joseph Dubé  Gabriel Venne 《Anatomical sciences education》2021,14(5):675-681

As medical programs place increasing importance on competency-based training and surgical simulations for residents, anatomy laboratories, and body donation programs find themselves in a position of adapting to changing demands. To better assess the demand for “life-like” cadaveric specimens and evaluate the possible impacts that competency-based medical education could have upon the body donation program of McGill University, Canada, the authors tracked, over the course of the last 10 years, the number of soft-embalmed specimens, along with the number of teaching sessions and the residents enrolled in competency-based programs that are using cadaveric material. The results reveal that the number of soft-embalmed specimens used within residency training increased from 5 in 2009 to 35 in 2019, representing an increase from 6% of bodies to 36.5% of the total number of body donors embalmed in this institution. Correspondingly, the number of annual teaching sessions for residents increased from 19 in 2012 to 116 in 2019. These increases in teaching are correlated with increasing number of residents enrolled in competency-based programs over the last 3 years (Pearson r ranging from 0.9705 to 0.9903, and R² ranging from 0.9418 to 0.9808). Those results suggest that the new skill-centered curricula which require residents to perform specific tasks within realistic settings, exhibit a growing demand for “life-like” cadaveric specimens. Institutions’ body donation programs must, therefore, adapt to those greater need for cadaveric specimens, which presents many challenges, ranging from the logistical to the ethical.  相似文献   

A Symbiosis of Access: Proliferating STEM PhD Training in the U.S. from 1920–2010     

Fernandez  Frank  Baker  David P.  Fu  Yuan-Chih  Muñoz  Ismael G.  Ford  Karly Sarita 《Minerva》2021,59(1):79-98

Minerva - Over the course of the 20th century, unprecedented growth in scientific discovery was fueled by broad growth in the number of university-based scientists. During this period the American...  相似文献   

Early Years Parenting Mediates Early Adversity Effects on Problem Behaviors in Intellectual Disability     

Vasiliki Totsika  Richard P. Hastings  Eric Emerson  Chris Hatton 《Child development》2020,91(3):e649-e664

A family developmental framework was applied to data from families of children with intellectual disabilities to understand the role of parenting in the path from early adversity to problem behaviors in mid-childhood. Data from 9 months to 11 years tested the Family Stress Model in families of 555 children. Adversarial parenting between 3 and 5 years mediated the path from early adversity (family poverty and maternal psychological distress at nine months) to problem behaviors at 7 and 11 years. Positive parent–child relationship only mediated the path to conduct problems. Multiple mediation was not present. Early adversity impacts both positive parent–child relationship and adversarial parenting between three and five, but the latter is crucial for problem behaviors in mid-childhood.  相似文献   

Teaching a blind student anatomy during the Covid-19 pandemic     

Georga J. Longhurst B.Sc. .  M.Sc.  P.G.Cert.H.B.E.  S.P.Cert.  F.H.E.A. 《Anatomical sciences education》2021,14(5):586-589

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Power training in elite young soccer players: Effects of using loads above or below the optimum power zone     

Irineu Loturco  Lucas A. Pereira  Valter P. Reis  Chris Bishop  Vinicius Zanetti  Pedro E. Alcaraz 《Journal of sports sciences》2020,38(11-12):1416-1422

ABSTRACT

This study aimed to examine the effects of two jump squat (JS) training programs involving different loading ranges in under-20 soccer players during a preseason period. Twenty-three elite young soccer players performed sprint speed (at 5-, 10-, and 20-m), change-of-direction (COD) speed, JS peak-power (PP), and countermovement jump (CMJ) tests pre and post four weeks of training. Athletes were pair-matched in two groups according to their optimum power loads (OPL) as follows: lower than OPL (LOPL; athletes who trained at a load 20% lower than the OPL) and higher than OPL (HOPL; athletes who trained at a load 20% higher than the OPL). Magnitude-based inferences were used to compare pre- and post-training measures. Meaningful increases in the PP JS were observed for both groups. Likely and possible improvements were observed in the 5- and 10-m sprint velocity in the LOPL group. Meanwhile, possible and likely improvements were observed in the CMJ, 5- and 10-m sprint velocity, and COD speed in the HOPL group. Overall, both training schemes induced positive changes in athletic performance. Soccer coaches and sport scientists can implement the JS OPL-based training schemes presented here, either separately or combined, to improve the physical performance of youth soccer players.  相似文献   

Trajectories of Adjustment in a Brazilian Sample of Street-Involved Youth     

Rebeca Fernandes Ferreira Lima  Marcela Raffaelli  Normanda Araujo de Morais  Juliana P. Santana  Carlos J. Nieto  Silvia H. Koller 《Child development》2020,91(4):1237-1253

Trajectories of adjustment were examined in a sample of street-involved youth across a 1-year period. Participants (N = 113; M_age = 14.18 years; 80.5% male, 91% non-White) were recruited in three Brazilian cities. Interviews conducted at three time points included six measures of physical and psychological adjustment. Unconditional growth models revealed linear declines over time (i.e., improved adjustment) on three indicators: health symptoms, sexual risk behaviors, and negative affect. There were no linear changes in drug use, positive affect, or life satisfaction. Conditional growth models revealed few significant effects for age or gender, but ratings of stressful life events moderated longitudinal changes in health symptoms, drug use, and negative affect. Implications for practice, policy, and theory are discussed.  相似文献   

浙江省第十五届大学生运动会高职高专院校竞赛成绩格局特征分析     

黄燕飞 《浙江体育科学》2020,(3):103-108

以文献资料法、数理统计法、比较法和逻辑归纳法等研究方法,通过对浙江省高职高专院校第十五届大学生运动会竞赛成绩的格局特征分析,得出以下基本结论:①十个大运会比赛项目分值赋分存在不均衡特征;②参赛院校在得分获奖能力方面具有明显的规模优势和类型强势特征;③十个大运会比赛项目具有十分明显的强校特征和获奖面局部离散性特征;④不同地域、不同性质院校在获奖能力方面的总体无差异性特征。在此基础上提出了实施三小球比赛得分两倍倍率激励制度设计,加强竞赛格局战略分析,科学谋划校外运动竞赛参赛整体计划,扬长避短,提升参赛绩效。运动竞赛整体强势学校须注重田径、游泳和三个大球类项目对整体获奖能力评价的重要贡献率,竞赛整体弱势学校可择取田径、羽毛球和游泳项目参赛获奖面相对较广、单项设置数较多的比赛项目等对策建议。  相似文献