Body composition differences by age and playing standard in male rugby union and rugby league: A systematic review and meta-analysis     

Tom Geeson-Brown  Ben Jones  Kevin Till  Sarah Chantler  Kevin Deighton 《Journal of sports sciences》2020,38(19):2161-2176

ABSTRACT

This systematic review and meta-analysis aimed to determine differences in body compositionn between playing standard and age in male rugby union and rugby league athletes. The MOOSE (Meta-analysis of Observational Studies in Epidemiology) guidelines for design, implementation, and reporting were followed. Studies were required to be in male rugby union or league and have body composition as the primary or secondary outcome. Data was required to be presented separately for positional groups and body composition presented as whole-body. A systematic search was performed in PubMed, Cochrane Library, MEDLINE, SPORTDiscus, and CINHAHL via EBSCOhost. 57 studies were included for meta-analysis. Results highlighted significantly higher fat-free mass in senior elite than senior sub-elite or junior elite athletes for all RU and RL forwards. Small and non-significant differences were found in fat mass between rugby union playing standards and age categories. Rugby league senior elite forwards had less fat mass than junior elite forwards. Practitioners should prioritise training and nutritional strategies that maximise fat-free mass development, especially in junior elite cohorts.  相似文献   

植物转基因沉默     

谷维娜  王建辉 《保定师专学报》2002,15(4):20-23

转基因沉默分为两种水平:第一种是转录水平上的基因沉默,发生原因主要是位置效应、异染色质化以及甲基化;第二种是转录后水平上的基因沉默,发生原因是通过对靶标RNA进行特异性降解而使基因失活,并就此研究提出RNA阈值模型、异常RAN模型、分子间(内)配对模型与RNA干涉模型来解释这种现象产生的机制。  相似文献   

试析我国司法独立理论与实践的偏差     

杨艳茹 《辽宁师范大学学报(社会科学版)》2002,25(3):10-12

司法独立是我国法制现代化历程进程中的关键问题。目前，虽然在理论上我国司法独立有宪法依据，但实践中面临着许多严峻问题，司法受到各方面干预而不能独立的现状已是不争的事实。造成这种状况的原因是多方面的；有领导体制和监督机制方面的原因；有司法自身方面的原因；有社会化方面的原因；有法律本身不完善方面的原因；有历史的和经济的方面原因。  相似文献   

缀饰态表象下二能级原子系统的跃迁理论     

伏振兴 《宁夏师范学院学报》2007,28(6):1-5

利用缀饰态表象讨论了二能级原子系统的跃迁过程;从量子干涉的角度对原子跃迁过程给出了非常清晰的理论描述.在其表述中揭示出脉冲面积在量子干涉效应中扮演着十分重要的相位因子功能,表明了激发光场的演变对原子跃迁的控制作用.  相似文献   

Effects of glucose–fructose versus glucose ingestion on stride characteristics during prolonged treadmill running     

Patrick B. Wilson  Stacy J. Ingraham 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(3):270-282

Scarce research has examined the effects of carbohydrate composition on running stride characteristics. On two occasions, 14 males and 6 females completed a 120-min sub-maximal run followed by a 4-mile time trial. Participants consumed glucose (GLU) or glucose–fructose (GLU–FRU) beverages supplying 1.3 g/min carbohydrate. Substrate use, psychological affect [Feeling Scale (FS)], and stride characteristics (stride frequency, stride length, and contact time) were assessed. Effects were expressed as Cohen’s d (90% confidence limits [90% CL]). CLs for stride frequency differences at 53 min (90% CL = 0.04–0.21) and 113 min (90% CL = 0.02–0.24) did not cover 0, indicating a positive effect of GLU–FRU. However, effect sizes were small (d = 0.13) and likely-to-very-likely trivial. Energy expenditure differences at sub-maximal end were very likely trivial (d = 0.08; 90% CL = 0.00–0.17), while FS ratings were possibly higher for GLU–FRU at 50 (d = 0.19; 90% CL = ?0.10–0.48) and 110 min (d = 0.16; 90% CL = ?0.13–0.45). During the time trial, stride length was possibly higher with GLU–FRU (d = 0.13; 90% CL = ?0.08–0.33). Glucose–fructose co-ingestion has no significant effect on stride characteristics during constant-velocity running but may result in slightly higher stride length during self-paced running.  相似文献   

PCS抗干扰问题的应用     

邓睿 《连云港师范高等专科学校学报》2004,(2):92-95

分析了电磁干扰及其对PCS干扰的来源，指出在实际应用时要综合考虑PCS的抗干扰性能，并结合实际提出了几种抗干扰措施。  相似文献   

雷达对抗模拟训练系统设计     

李鸣 《教育教学论坛》2019,(29):73-75

在分析了雷达对抗与反对抗模拟训练系统功能需求的基础上,设计了一种基于分布式局域网络的模拟训练系统。实践证明,该设计功能齐全、技术成熟、运行稳定,能够独立地形成训练所需的战场环境和电磁态势,对同类模拟训练设备的设计开发具有借鉴意义。  相似文献   

二语写作中母语负迁移对句法层面的影响及对策     

胡彩霞 《海外英语》2011,(9):333-334,344

二语写作中母语负迁移的影响客观存在而且涉及到写作的各个环节。句子作为表达独立完整观点、构建段落篇章的基本单位起着至关重要的作用。因此,分析和探究母语负迁移对句法造成的影响有利于写作教学的有效开展。  相似文献   

基于Matlab GUI的薄膜干涉仿真     

李继军  程庆华  杨长铭 《洛阳师范学院学报》2011,30(11):16-19,22

为动态反映薄膜干涉图样随波长和干涉装置的几何参数的改变而产生的变化,利用Matlab图形用户界面的设计和开发功能,结合真实的可见光谱,制作了劈尖干涉、牛顿环干涉以及迈克尔逊干涉的交互式图形仿真界面.仿真结果图形细致逼真,使该过程的物理规律直观形象,有助于学生理解这几种典型薄膜干涉过程中的物理规律.  相似文献   

双语词汇通达：理论、范式及其研究进展     

王亚鹏  李继利  丁小兵 《宁波大学学报(教育科学版)》2011,33(5):19-24

从双语词汇通达的理论假设、研究范式、实验研究等方面介绍了当前双语词汇通达的研究现状与进展。指出了目前双语词汇通达研究面临的一些问题以及未来的研究方向,认为未来的研究一方面要运用多种研究范式探讨双语词汇通达的机制,另一方面要探讨双语词汇通达的机制是否因为双语类型的不同而不同。  相似文献