Biological maturity-associated variance in peak power output and momentum in academy rugby union players

The study aimed to evaluate the mediating effect of biological maturation on anthropometrical measurements, performance indicators and subsequent selection in a group of academy rugby union players. Fifty-one male players 14–17 years of age were assessed for height, weight and BMI, and percentage of predicted mature status attained at the time of observation was used as an indicator of maturity status. Following this, initial sprint velocity (ISV), Wattbike peak power output (PPO) and initial sprint momentum (ISM) were assessed. A bias towards on-time (n?=?44) and early (n?=?7) maturers was evident in the total sample and magnified with age cohort. Relative to UK reference values, weight and height were above the 90th and 75th centiles, respectively. Significant (p?≤?.01) correlations were observed between maturity status and BMI (r?=?.48), weight (r?=?.63) and height (r?=?.48). Regression analysis (controlling for age) revealed that maturity status and height explained 68% of ISM variance; however, including BMI in the model attenuated the influence of maturity status below statistical significance (p?=?.72). Height and BMI explained 51% of PPO variance, while no initial significant predictors were identified for ISV. The sample consisted of players who were on-time and early in maturation with no late maturers represented. This was attributable, in part, to the mediating effect of maturation on body size, which, in turn, predicted performance variables.     

Growth and maturity status of elite British junior tennis players

Growth and maturation impact the selection, development and progression of youth athletes. Individual differences in the growth and maturity may afford a performance advantage, clouding coaches and practitioners’ perceptions regarding current ability and future potential. This may result in the exclusion of talented, yet less physically gifted athletes. Participants were 91 male (n = 47) and female (n = 44) elite British Junior tennis players, 8–17 years of age (12.5 ± 1.9 years). Height and body mass were measured and compared to growth charts; hand-wrist radiographs were taken. Skeletal age (SA) was estimated with the Fels method and contrasted to chronological age (CA). Mean height and body mass of individual players ranged between the 50th and 90th centiles for age and sex. Females were advanced in SA relative to CA (0.3–0.89 years.) from 8 years. Males were average to delayed in maturation from 8 to 12 years, but advanced in SA from 14 to 16 years (0.75–1.23 years). Individual differences in growth and maturation appear to contribute towards the selection of elite junior tennis players, with a bias towards males and females who are advanced in maturation and comparatively tall and heavy for their age. This has important implications for talent identification and development.     

海水也分层

光合作用带 这里聚集了大部分的光与热,藻类能充分进行光合作用.大多数海洋生物都生活在这个区域,其中包括浮游生物、软体动物、 中层带 光合作用带之下,200～1000米深的水层,虽有微弱的光线透入,却不足以促使藻类进行光合作用,因此,人们常将此水层形象地称为"暮光区",这里的水深1000～4000 米的区域,又被称为宁静...     

纸杯打鸣

<正>本期我们为大家准备了一个有趣的物理实验。借助生活中的常见物品,你不但能制作出形态逼真的发声模型,还可以将其中的原理与弦乐器相联系,探索悠扬旋律背后的奥秘。【实验材料】基本用具:一次性纸杯,缝衣针(可用锥子代替),剪刀,粗棉线,直尺,曲别针,纸巾装饰材料:彩纸,胶水,活动眼睛,橡皮泥注意:请在成年人的帮助下使用针和剪刀,以免发生意外。【操作步骤】1首先,我们来制作基础版的纸杯模型。请你用缝衣针在杯底中央戳一个小洞。2用直尺量取30厘米长的棉线绳,将其一端穿过杯底的小孔,另一端系在曲别针上。拉紧绳子,使曲别针紧贴在杯底外侧。     

An examination of the importance of performances in youth and junior competition as an indicator of later success in tennis

Talent identification at a young age is deemed essential for many national sporting organisations to increase the chances of success for their players on the international stage. Talent identification methods can be imprecise and national tennis associations and coaches often identify talent based on performances at youth tournaments and junior rankings. However, not much is known about the relationship between the international competition performances of young tennis players and later success. This relationship is explored in this study using comparisons based on: (a) the results of 3521 players at U14 youth tournaments; (b) the rankings of 377 junior players (U18) by the International Tennis Federation; (c) the rankings of 727 professional male players by the Association of Tennis Professionals; and (d) the rankings of 779 professional players by the Women's Tennis Association. Junior performances (U18) and performances at youth tournaments (U14) appear to have a low success rate in predicting later success. No distinct age was found at which players should start to perform in order to be successful at the professional level. It is concluded that even though good performances at young ages increase athletes’ chances to become elite players, they are not a precondition for achieving later success. Therefore, this study informs talent scouts, sport development officers, coaches and high performance managers of the role that performances at international youth competitions may play in talent identification in tennis.     

Expanding horizons for students with dyslexia in the 21st century: universal design and mobile technology

This paper discusses the role of mobile technology in supporting people with dyslexia within the theoretical framework of Universal Design for Learning. The authors discuss how students with dyslexia can use mobile technology to address a diverse range of academic needs (such as reading, composing text, notetaking, metacognition and studying skills). Curriculum issues and teacher training are also examined.     

Analysis of Parent,Teacher, and Consultant Speech Exchanges and Educational Outcomes of Students With Autism During COMPASS Consultation

The significant increase in the numbers of students with autism combined with the need for better trained teachers (National Research Council, 2001) call for research on the effectiveness of alternative methods, such as consultation, that have the potential to improve service delivery. Data from 2 randomized controlled single-blind trials indicate that an autism-specific consultation planning framework known as the collaborative model for promoting competence and success (COMPASS) is effective in increasing child Individual Education Programs (IEP) outcomes (Ruble, Dalrymple, & McGrew, 2010 Ruble, L. A., Dalrymple, N. J. and McGrew, J. H. 2010. The effects of consultation on Individualized Education Program outcomes for young children with autism: The collaborative model for promoting competence and success. Journal of Early Intervention, 32: 286–301. doi:10.1177/1053815110382973[Crossref], [PubMed] , [Google Scholar]; Ruble, McGrew, & Toland, 2011 Ruble, L., McGrew, J. and Toland, M. Randomized controlled study of teacher training in autism. Poster session presented at the meeting of the American Psychological Association. Washington, DC. August.  [Google Scholar]). In this study, we describe the verbal interactions, defined as speech acts and speech act exchanges that take place during COMPASS consultation, and examine the associations between speech exchanges and child outcomes. We applied the Psychosocial Processes Coding Scheme (Leaper, 1991 Leaper, C. 1991. Influence and involvement in children's discourse: Age, gender, and partner effects. Child Development, 62: 797–811. doi:10.1111/j.1467-8624.1991.tb01570.x[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) to code speech acts. Speech act exchanges were overwhelmingly affiliative, failed to show statistically significant relationships with child IEP outcomes and teacher adherence, but did correlate positively with IEP quality.     

The Relation Between Walking and Language in Infant Siblings of Children With Autism Spectrum Disorder

In typical development, walk onset is accompanied by increased language growth (e.g., Walle & Campos, 2014). The present study explored whether this relation may be disrupted in the infant siblings of children with autism spectrum disorder (ASD; heightened risk of receiving an ASD diagnosis; HR), a population exhibiting substantial variability in motor and language development (e.g., Gamliel, Yirmiya, & Sigman, 2007; Landa & Garrett-Mayer, 2006). Receptive and expressive language were examined across the transition to walking in three groups of HR infants (no diagnosis, language delay, and ASD; N = 91, 8–18 months) and in infants with no family history of ASD (N = 25; 9–15 months). Only infants with an eventual ASD diagnosis did not show increased language growth following walk onset.     

Scientific epistemic beliefs, conceptions of learning science and self-efficacy of learning science among high school students

This study examined the relationships among Taiwanese high school students’ scientific epistemic beliefs, conceptions of learning science, and self-efficacy of learning science. The questionnaire responses gathered from 377 high school students in Taiwan were utilized to elicit such relationships. The analysis of the structural equation model revealed that students’ absolutist scientific epistemic beliefs led to lower-level conceptions of learning science (i.e. learning science as memorizing, preparing for tests, calculating, and practicing) while sophisticated scientific epistemic beliefs might trigger higher-level conceptions of learning science (i.e. learning science as increase of knowledge, applying, and attaining understanding). The students’ lower-level conceptions of learning science were also found to negatively associate with their self-efficacy of learning science, while the higher-level conceptions of learning science fostered students’ self-efficacy. However, this study found that students who viewed scientific knowledge as uncertain (advanced epistemic belief) tended to possess lower self-efficacy toward learning science.     

Measuring athlete imagery ability: the sport imagery ability questionnaire

This research aimed to develop and provide initial validation of the Sport Imagery Ability Questionnaire (SIAQ). The SIAQ assesses athletes' ease of imaging different types of imagery content. Following an extensive pilot study, 375 athletes completed a 20-item SIAQ in Study 1. Exploratory factor analysis revealed a 4-factor model assessing skill, strategy, goal, and affect imagery ability. Confirmatory factor analysis (CFA) established this 4-factor structure in Study 2 (N = 363 athletes). In Study 3 (N = 438 athletes), additional items were added to create a fifth mastery imagery subscale that was confirmed through CFA. Study 4 (N = 220 athletes) compared the SIAQ to the Movement Imagery Questionnaire-3. Significant bivariate correlations (p < .05) confirmed the SIAQ's concurrent validity but demonstrated differences in imagery ability of different content. Overall, the SIAQ demonstrates good factorial validity, internal and temporal reliability, invariance across gender, and an ability to distinguish among athletes of different competitive levels. Findings highlight the importance of separately assessing imagery ability of different content.