Sprint running kinematics and kinetics in pre-peak-height-velocity male children on a non-motorised treadmill: reliability and normative data

The purpose of this study was to quantify the reliability of kinematic and kinetic variables using a sample of pre-peak-height-velocity (PHV) male athletes sprinting on a non-motorised treadmill. Following variables were measured and their normative data presented, average and peak velocity, average and peak power, average and peak horizontal force, average and peak vertical force, average step frequency, average step length, average work. Twenty-five participants performed three 5-s all-out sprints from a standing split start on a non-motorised treadmill on three separate occasions. Per cent change in the means (-3.66 to 3.35%) and coefficients of variation (0.56–7.81%) were thought reliable for all variables. However, average step rate, average horizontal force and average vertical force did not meet the standards (≥0.70) set for acceptable intraclass correlation coefficients (ICC). Due to the homogeneous group, it was expected to receive low ICC values. Therefore, youth sprinting performance can be tested reliably on a non-motorised treadmill, especially if the per cent change in the mean and CV are deemed the important reliability measures. Normative data are given for the participant’s age as well as their maturity level for kinematic and kinetic variables.     

Age and maturity related differences in motor coordination among male elite youth soccer players

This study investigated differences in generic and soccer specific motor coordination, as well as speed and agility depending on age and maturity in elite youth soccer players (U10-U15, N = 619). Measurements included body height, body weight and sitting height to estimate age at peak height velocity (APHV); three Körperkoordinationstest für Kinder subtests (i.e. jumping sideways (JS), moving sideways (MS), balancing backwards (BB)) to assess generic motor coordination; the UGent dribbling test for soccer specific motor coordination; a 5m/30m sprint and T-test for speed and agility, respectively. Age specific z-scores of the predicted APHV identified players as earlier, on time or later maturing. (M)ANOVA analyses showed significant age by maturity interaction effects for the speed and agility test cluster, revealing maturity related differences in U14 and U15 players. Next to an overall higher performance with age for all test clusters (η² 0.080–0.468), earlier maturing players outperformed their later maturing peers in 5m/30m sprinting. The opposite was seen for JS and BB. So, players’ maturity status should be taken into account to adequately value performance in talent identification. Also, the focus on characteristics that appear to be minimally biased by an earlier maturational timing (i.e. motor coordination) should be increased.     

储光羲的仿古心态及其致力五古的缘由

储光羲擅长五言古诗的创作,其五古诗歌中具有明显的仿古倾向。因为诗坛的复古潮流,东南诗人群体的整体创作趣尚,储光羲听从性格、思想等内在特质的召唤,形成了对五言古诗的特殊偏好。     

Relative Age Effect and Gender Differences in Physical Education Attainment in Norwegian Schoolchildren

The relative age effect (RAE) refers to that children born early in their year of birth show higher performance compared to children born late in the same cohort. The present study evaluated whether RAE exists within non-competitive physical education (PE) attainments, change in RAE magnitude with age, and possible gender differences. The results show a drop in PE attainment and a difference in number of high and low marks between the first and second half-year. Of the pupils who attained the highest mark, 73% were born in the first 6 months. In lower-secondary school, RAEs were larger in girls compared with boys. A possible explanation for the results is that the PE-teachers might be inspired by product-oriented criteria.     

论主体性与教师成长

从多角度提出弘扬教师成长与发展的主体性的必要性和必然性，并对教师主体性的内涵、结构和特点进行粗浅的分析，同时，提出了教师如何实现主体性的成长与发展的几点建议。     

Teaching and learning centres: towards maturation

Approximately 70% of Australian Teaching and Learning Centres have been restructured and/or have undergone leadership changes in the last three years. The volatility of this environment reflects the number of significant challenges faced by Teaching and Learning Centres. In determining what makes Centres successful, the issues that are likely to impact on their ability to succeed were examined. It emerged that a myriad of factors influence whether or not a Centre was recognised as being an integral and valued part of the university's teaching and learning community – a hallmark of having reached maturity. This paper identifies four factors as being critical to the ability of Centres to succeed, noting that a combination of other factors, appropriate to each unique context, must also be in place in order for Centres to maximise their value.     

中国文人五、七言诗产生新论

中国诗歌杂有五、七言或民间五、七言歌谣,溯其源则年代久远,而中国文人五言诗的产生则在西汉初,并非始于东汉班固的《咏史诗》,中国文人七言诗的雏形也产生于西汉,并非始于曹丕的《燕歌行》。文人五、七言诗发展至汉末,各种艺术技巧基本成熟,它上承诗骚体,下启永明体,惠及近体,完成了中古诗歌的重大转型,对后世格律诗的产生做出了重要的贡献。     

A Latent Growth Curve Approach to Investigating Developmental Dynamics and Correlates of Change in Children's Perceptions of Physical Competence

Abstract

In both the physical and academic domains interest has recently grown regarding developmental change in children's perceptions of competence. Recent advances in statistical methodology, such as latent growth modeling, enable the researcher to analyze developmental trends from both an inter- and intraindividual perspective, thus serving to increase our understanding of correlates of change in perceived competence. Using latent growth modeling, the purpose of the present study was to investigate developmental change in children's perceived competence at physical skills, examining maturational factors and chronological age as possible correlates of change. Subjects were male adolescents (N = 94). Data were collected during the child's sixth, eighth, and ninth grade school years. Results revealed a good fit for the hypothesized model, which specified mean level changes in the variables over time and an interrelationship among the latent chronometric common factors. Although a significant relationship existed between maturation and perceived competence, no significant relationship was evident between chronological age and perceived competence. Findings are discussed with particular reference to the utility of latent growth curve models for assessing developmental processes at both the inter- and intraindividual level.     

Estimated maturity status and perceptions of adult autonomy support in youth soccer players

Abstract

In this study, we examined the relations between biological maturity status, body mass index, age, and perceptions of adult autonomy support in the context of youth soccer. A total of 70 female and 43 male soccer players, aged 9 – 15 years, completed three adult-specific versions (i.e. mother, father, coach) of the perceived autonomy support subscale from the Interpersonal Style Scale. The participants' percent predicted adult stature was used as an estimate of biological maturity status. Multiple linear regression analyses revealed that advanced maturity status in male players predicted lower perceptions of autonomy support from the coach. Maturity status was unrelated to perceptions of autonomy support from the coach in female soccer players, and paternal and maternal autonomy support in male and female players. Age and body mass index were unrelated to perceptions of adult (i.e. coach, mother, father) autonomy support in male and female players.     

论五言诗的韵律与体式的意义

在中国的旧体诗中,在《诗经》《楚辞》之后,首先发展起来的是汉魏六朝时代的五言诗,唐代人称此为古诗,以别于唐代人按严格体式和韵律写的属于＂近体诗＂范畴的五言绝句、五言律诗、五言长律。由于五绝、五律诗每句中的5个字是前两字一顿、后三字一顿的句法结构,正是与七绝、七律诗句的后5字构词顿数相同,以至与许多词的五字句顿式一致,所以五言律句的构制,就成了诗词写作合于韵律的必须具备的实践准备条件。在五言诗的写作上,五言绝句的难度更大,因为每首诗只有20个字,且要独立成章,因此必须立意集中,不枝不蔓;文字精妙,难于增减;借端托寓,蓄意深微;意到辞工,不假雕饰。由于五言绝句的体式精微,施展的天地极小,所以历来虽有名篇,却少有独擅此体的名家。