The effects of school-based physical activity interventions on students' health-related fitness knowledge: A systematic review

This systematic review includes 34 studies examining the effects of school-based physical activity interventions on students' health-related fitness knowledge. The study design, methodological quality, and effectiveness of interventions on students' health-related fitness knowledge were analysed. The majority of the studies (79.4%) revealed significant positive intervention effects on students' health-related fitness knowledge. Studies examining adolescents were more frequently in a position to influence students' health-related fitness knowledge (87.5%) than studies examining children (75%), and studies with low methodological quality (88.8%) had more frequent positive effects than studies with moderate quality (75%). The effects on students' health-related fitness knowledge were independent of moderator variables such as the intervention content, duration and frequency. Only few studies were able to simultaneously positively influence students' health-related fitness knowledge and students' physical activity and/or fitness levels. These programmes can positively influence students' health-related fitness knowledge, but it remains unclear what the practical significance of these changes is. Further research is needed to clarify the influence of students' health-related fitness knowledge on reflection, understanding, physical activity behaviour, and overall physical literacy levels.     

Comparing the magnitude and direction of asymmetry during the squat,countermovement and drop jump tests in elite youth female soccer players

ABSTRACT

The aims of the present study were to provide an in-depth comparison of inter-limb asymmetry and determine how consistently asymmetry favours the same limb during different vertical jump tests. Eighteen elite female under-17 soccer players conducted unilateral squat jumps (SJ), countermovement jumps (CMJ) and drop jumps (DJ) on a portable force platform, with jump height, peak force, concentric impulse and peak power as common metrics across tests. For the magnitude of asymmetry, concentric impulse was significantly greater during the SJ test compared to CMJ (p = 0.019) and DJ (p = 0.003). No other significant differences in magnitude were present. For the direction of asymmetry, Kappa coefficients revealed fair to substantial levels of agreement between the SJ and CMJ (Kappa = 0.35 to 0.61) tests, but only slight to fair levels of agreement between the SJ and DJ (Kappa = ?0.26 to 0.18) and CMJ and DJ (Kappa = ?0.13 to 0.26) tests. These results highlight that the mean asymmetry value may be a poor indicator of true variability of between-limb differences in healthy athletes. The direction of asymmetry may provide a useful monitoring tool for practitioners in healthy athletes, when no obvious between-limb deficit exists.     

Components of Variance of Scales With a Bifactor Subscale Structure From Two Calculations of α

Since Cronbach's (1951) elaboration of α from its introduction by Guttman (1945), this coefficient has become ubiquitous in characterizing assessment instruments in education, psychology, and other social sciences. Also ubiquitous are caveats on the calculation and interpretation of this coefficient. This article summarizes a recent contribution (Andrich, 2015) on the use of coefficient α which complements these many caveats. It shows that in the presence of a simple bifactor structure of a scale where unique components of variance are homogeneous in magnitude, three components of variance and the common latent common correlation among the subscales can be calculated from the ratio of two calculations of α, one at the level of the items, the other at the level of the subscales. It was suggested that these two ready calculations and their interpretation, and the reporting of all four indices in the analysis of scales with a subscale structure, would reduce the misinterpretation of this coefficient. An illustrative example of the application of the calculations is also shown.     

TPR技术对钒系催化剂供氧活性和数目的研究

本文报导了利用TPR技术研究钒系催化剂的供氧活性和数目,从而阐明了TPD平衡法的可靠性.     

艺术的情境之寓——文艺美学探微

情境者,情趣境界之谓也,主于美。它存在于艺术作品中,也存在于整个艺术审美活动中。艺术没有唯一的和绝对的摹本,也没有终级价值标准,有的便是一件件具体的作品和一次次具体的活动。一件作品就是一个独绝的情境,这情境是别人创造不出的,甚至创造者自己都是不能重复的。在此情境中,包括每一个细部,即使如绘画中的一处空白,音乐中的一个休止,小说中的一段铺垫,等等,便有着特别的意味,特别的美质。     

论文学功能系统与特质

传统的作品功能观把本视为学功能的发生源，把读视为学功能作用的被动对象，本提出：学功能必须在具体的学活动中才能产生，学活动是学功能的发生源。学功能联系于学活动的动态开放整体的流程，并对投身于学活动的一切实践主体（作与读）产生系统效能，学功能系统由认知，净化，愉悦，生命四个各具丰富内涵的子系统构成，并通过系统质的审美化合指向人本身，指向人自身的丰富与完善，指向人的诗意人生，因此，学功能是学之人学本义的回归。     

运算放大器工作状态的判断及分析

在电子技术教学中,分析运算放大器系统时,应根据运算放大器系统的反馈情况,判断它的工作状态;分析工作状态时,要充分考虑运放系统是处于线性区还是饱和区。线性区可按虚短或虚地原则处理,饱和时不能按虚短原则处理,应用“虚短”和“虚地”时应注意“虚短”是“虚地”的特殊形式。     

5-氨基四唑及其衍生物的合成和应用综述

文章综述了5-氨基四唑及其4种衍生物高氯酸.四氨.双(5-硝基四唑)合钴(Ⅲ)(BNCP)、3,6-双(l-氢-l,2,3,4-四唑-5-氨基)-l,2,4,5-四嗪(BTATz)、5-氨基四唑的Schiff碱、α-(5-四唑基)氨基烃基膦酸酯的合成、性质与应用.     

酒精体胀系数的测量方法

利用酒精温度计法测定玻璃体内酒精的体胀系数。     

大学生择业法律意识淡漠的成因及对策

面对就业市场的激烈竞争,大学生必须具备相应的择业意识才能在竞争中抓住机遇,顺利完成择业过程。但在择业过程中,由于大学生缺乏择业法律意识卷入了择业的劳动纠纷。从维权意识、契约意识、公民意识和对违法行为性质的认识四个角度对大学生的择业法律意识进行分析。