Effects of purposeful soccer heading on circulating small extracellular vesicle concentration and cargo

BackgroundConsidering the potential cumulative effects of repetitive head impact (HI) exposure, we need sensitive biomarkers to track short- and long-term effects. Circulating small extracellular vesicles (sEVs) (<200 nm) traffic biological molecules throughout the body and may have diagnostic value as biomarkers for disease. The purpose of this study was to identify the microRNA (miRNA) profile in circulating sEVs derived from human plasma following repetitive HI exposure.MethodsHealthy adult (aged 18–35 years) soccer players were randomly assigned to one of 3 groups: the HI group performed 10 standing headers, the leg impact group performed 10 soccer ball trapping maneuvers over 10 min, and the control group did not participate in any soccer drills. Plasma was collected before testing and 24 h afterward, and sEVs were isolated and characterized via nanoparticle tracking analysis. Next-generation sequencing was utilized to identify candidate miRNAs isolated from sEVs, and candidate microRNAs were analyzed via quantitative polymerase chain reaction. In silico target prediction was performed using TargetScan (Version 7.0; targetscan.org) and miRWalk (http://mirwalk.umm.uni-heidelberg.de/) programs, and target validation was performed using luciferase reporter vectors with a miR-7844-5p mimic in human embryonic kidney (HEK) 293T/17 cells.ResultsPlasma sEV concentration and size were not affected across time and group following repetitive HI exposure. After 24 h, the HI read count from next-generation sequencing showed a 4-fold or greater increase in miR-92b-5p, miR-423-5p, and miR-24-3p and a 3-fold or greater decrease in miR-7844-5p, miR-144-5p, miR-221-5p, and miR-22-3p. Analysis of quantitative polymerase chain reaction revealed that leg impact did not alter the candidate miRNA levels. To our knowledge, miR-7844-5p is a previously unknown miRNA. We identified 8 miR-7844-5p mRNA targets: protein phosphatase 1 regulatory inhibitor subunit 1B (PPP1R1B), LIM and senescent cell antigen-like domains 1 (LIMS1), autophagy-related 12 (ATG12), microtubule-associated protein 1 light chain 3 beta (MAP1LC3B), integrin subunit alpha-1 (ITGA1), mitogen-activated protein kinase 1 (MAPK1), glycogen synthase kinase 3β (GSK3β), and mitogen-activated protein kinase 8 (MAPK8).ConclusionCollectively, these data indicate repetitive HI exposure alters plasma sEV miRNA content, but not sEV size or number. Furthermore, for the first time we demonstrate that previously unknown miR-7844-5p targets mRNAs known to be involved in mitochondrial apoptosis, autophagy regulation, mood disorders, and neurodegenerative disease.     

Relative age and maturation selection biases in academy football

ABSTRACT

This study examined the simultaneous effects of relative age and biological maturity status upon player selection in an English professional soccer academy. A total of 202 players from the U9 to U16 age groups, over an eight-year period (total of 566 observations), had their relative age (birth quarter) and biological maturity (categorised as late, on-time or early maturing based upon the Khamis-Roche method of percentage of predicted adult height at time of observation) recorded. Players born in the first birth quarter of the year (54.8%) were over-represented across all age groups. A selection bias towards players advanced in maturity status for chronological age emerged in U12 players and increased with age; 0% of players in the U15 and U16 age group were categorised as late maturing. A clear maturity selection bias for early maturing players was, however, only apparent when the least conservative criterion for estimating maturity status was applied (53.8% early and 1.9% late maturing in the U16 age group). Professional football academies need to recognise relative age and maturation as independent constructs that exist and operate independently. Thus, separate strategies should perhaps be designed to address the respective selection biases, to better identify, retain and develop players.     

我国优秀青少年男子足球队教练员领导行为的研究

本文通过《运动领导行为量表》(简称LSS)对中国青少年足球运动员喜爱的及教练员实际的领导行为进行了测量与研究，分析了领导行为维度指标与运动员特征。教练员特征及比赛成绩等因素之间的关系。研究结果表明：不同年龄、不同运动年限和不同位置的运动员对教练领导行为的喜爱程度不一样；年龄、执教年限或运动年限不同的教练员实际的领导行为之间差异显著；不同成绩组球队运动员喜爱的及其教练员实际的领导行为之间也存在着显著性差异。     

岩巷下山施工技术探讨

开滦钱家营矿业公司在矿井衔接紧张的情况下，优先安排下山施工-600水平以下八采区，十采区的大部分开拓工程，在施工初期，由于受施工技术，管理水平限制工程进度慢、效率低不能满足生产要求，通过采用光面爆破新技术、科学选择和利用施工设备、合理调整工序充分利用工时，提高了施工效率，使施工进度、工程质量得到明显提高，为矿井的总体衔接提供了基础保障。     

足球运动肌肉损伤后功能恢复手段的研究与发展

肌肉损伤是足球运动损伤的主要类型,对于肌肉损伤后功能恢复手段的研究与发展一直是现代足球运动发展过程中亟待解决的重要课题.本文主要采用文献资料、逻辑分析、归纳比较等研究方法,通过对足球运动损伤的类型及损伤后肌肉功能恢复的机制进行研究分析,重点提出了肌肉功能恢复的3种主要治疗手段:中医疗法、运动疗法以及药物疗法.最后对足球运动损伤后肌肉功能恢复手段的发展趋势做了进一步的探讨.     

洱海周边农田水稻抽穗期害虫及害虫天敌资源初步调查

2007年7-8月对洱海周边的下关、大理、喜洲、上关、双廊、挖色、海东、满江的水稻抽穗期稻田蜘蛛及昆虫资源进行了初步调查,共采集的节肢动物13225头,其中害虫2879头,害虫天敌2211头,鉴定结果显示：洱海周边地区水稻抽穗期稻田害虫有10种,隶属4目6科8属,害虫天敌46种,隶属5目18科27属。其中,挖色、上关、双廊、喜洲、下关、满江、海东和大理地区的害虫物种分别占整个洱海周边地区水稻抽穗期稻田害虫物种总数的80％、80％、70％、70％、50％、50％、50％和40％;害虫天敌分别为52％、50％、46％、46％、41％、39％、37％和35％。     

学习型教练员团队建设研究——试论足球科研教练员培养

学习型教练员团队的建立是科技发展的必然结果,其内容更具时代特征,更接近我国竞技体育教练员发展的需要;建立学习型教练员团队是有价值且可行的。通过论述我国足球科技工作的现状以及国外教练员体制的发展趋势,建立足球科技教练员体系的总体思路,并明确科技教练员的工作任务,为提高我国足球的整体水平提供借鉴。     

分层教学法在高校足球选项课中的运用研究

以大二男学生作为研究对象,通过实验:运用学生分层、目标分层、分层施教、分层练习测评、分层小结提高的教学方法,实行因材施教、实施异步教学,使学生在原有基础上得到逐步提高和发展,最终实现分层达标,个个进步。分层教学法不仅能够调动学生的学习积极性,提高教学质量,教学效果比传统教学法显著;而且还实现了因材施教,发展了学生个性。     

对影响足球运动员球感因素的研究

球感是足球运动员必须具备的基本功之一,是控制球的基础,是技术水平获得高度发展的前提。足球运动员技术动作完成质量的高低很大程度上依赖其对球感的熟练程度。球感的正确形成和发展是一个长期的过程。本文对影响足球运动员球感发挥的若干因素,即感觉敏锐度、足球意识、注意力分配能力、自信心、情绪以及对比赛规律的认识和把握进行了分析论证,力求找到各因素内在的积极影响并提出针对性的训练方法,旨在为足球运动员的球感训练及选材提供参考依据。     

网络支持下的西文名称规范工作

阐述图书馆规范控制工作的定义，认为规范工作是一个建立、跟踪、维护、使用和评估规范记录的全过程，是提高文献检索效率与工作效率的有效措施。以图书馆必做的名称规范工作为例，探讨如何利用网络信息轻松快捷地完成规范记录的具体操作措施，指出规范控制工作中合理利用网络信息是必要的，也是可行的。