间歇性低氧训练对游泳运动员运动能力影响的实验研究     

姜涛  叶鸣  雷志平 《西安体育学院学报》2007,24(4):71-75

目的旨在通过对高水平游泳运动员间歇性低氧训练(IHT)中血液指标变化的研究,进一步探求IHT的有关机制,为游泳运动项目建立相应的IHT模型,使IHT成为一种具有实用价值的有效辅助训练方法,促进运动成绩提高发挥作用。方法以陕西省游泳队男运动员为受试对象,在实验室条件下实施为期3 w氧浓度逐周递减的间歇性低氧训练,测试血液学指标、血乳酸、力竭时间、心率。结果(1)RBC、HB、HCT均在正常生理范围内,但有个体差异;WBC、Lymph%均在正常生理含量;(2)在逐级递增负荷中,间歇性低氧训练后运动员力竭时间延长,由1 606.57 s提高至1 689 s,力竭负荷由低氧训练前267.7 w提高到281.5 w;(3)乳酸阈功率在七位受试者中有一人下降,两人不变,四人提高,总体平均值提高12.25%。结论(1)血液指标检查结果IHT前后均在正常生理含量,说明IHT对于游泳运动员机能影响机制有别于高原训练;(2)经过IHT后,运动时间延长,表明IHT可以提高机体的耐力素质;(3)IHT后安静心率比训练前降低,且同级负荷时训练后心率始终低于训练前,表明心脏的输出功率增大;(4)乳酸阈强度提高充分显示IHT使运动员有氧代谢能力提高,运动能力增强。  相似文献   

传统高原训练、HiLo训练、间歇性低氧训练及高海拔地区交替训练(低住高训)的理论比较     

李登光  张晓东 《山西师大体育学院学报》2007,22(2):113-115,120

运用文献综述法和基础理论分析法,对传统高原训练、HiLo训练、间歇性低氧训练及高海拔地区交替训练(低住高训)理论进行了全面系统的理论分析。通过比较发现HiLo训练和间歇性低氧训练是较为优越的训练方法。  相似文献   

Where populist citizens get the news: An investigation of news audience polarization along populist attitudes in 11 countries     

Anne Schulz 《Communication monographs》2019,86(1):88-111

This article presents a secondary analysis of two multi-national cross-sectional surveys conducted in 2015 (11 countries, N?=?10,570) and 2017 (4 countries, N?=?2165) to examine the relationship between populist attitudes and media use. The results indicate that populist citizens are more likely to consume news than non-populist citizens. Specifically, populist citizens exhibit a preference for commercial television (TV) news, as well as a tendency to read tabloid newspapers. While they use fewer quality newspapers, public TV news are not systematically avoided. Regarding the online news environment, populist citizens prefer Facebook over Twitter as a source of political information. This selective pattern will be discussed in light of the debates on news audience polarization and political polarization.  相似文献   

News audience fragmentation in the Japanese Twittersphere     

Tetsuro Kobayashi  Takahisa Suzuki  Hitoshi Yamamoto 《亚洲交流杂志》2019,29(3):274-290

ABSTRACT

Although computational approaches to ideology-based audience fragmentation are promising, they are not without limitations. First, most existing studies have focused on the US, and the cross-national validity of their results has rarely been tested. Second, previous studies that rely solely on behavioral data from social media tend to make strong analytical assumptions such as that Twitter users prefer to follow media and politicians whose ideological positions are similar to their own, and that the ideologies of political elites can be extrapolated to infer the ideologies of ordinary users. We aim to address these limitations. First, we focus on Japan to test the generalizability of US findings in an Asian context. Second, we do not rely solely on behavioral measurement but combine survey and social media data to infer the ideologies of Twitter users. Results indicate that our classifier built based on these self-reported ideologies produces more valid estimates than naïve extrapolation from views of the elites. Based on these improved estimates of Twitter users’ ideologies, we demonstrate that the ideological distributions of those who follow major Japanese media accounts on Twitter largely overlap, suggesting an absence of ideology-based audience fragmentation.  相似文献   

露迹:新生代小说中的元小说叙事手法   总被引：1，自引：0，他引：1  

赵映环 《阜阳师范学院学报(社会科学版)》2015,(2)

"露迹"是最重要的元小说叙事手法之一,也是先锋小说家们常用的写作策略。"露迹"手法的使用是新生代小说对先锋小说多元化创作的一种继承。但新生代小说家们将"露迹"手法纳入了更为合理的范畴,摆脱了先锋元小说创作中"形式大于内容"的怪圈。  相似文献   

新媒体语境特征与用户态度关系构建的实证研究     

薛可  阳长征  余明阳 《湖南师范大学社会科学学报》2015,(3):153-160

通过对上海市民进行抽样调查,并使用结构方法模型对新媒体语境下的受众社会态度倾向进行实证研究,得出如下结论：新媒体语境通过社会懈怠对用户风险偏好和群体极化倾向产生正向影响,对责任与公平意识、道德发展以及亲社会倾向产生负向影响;媒体接触频率在新媒体与社会懈怠关系中具有显著正向调节作用,而媒体接触的多样性在其中的调节作用并不明显;在主效应和调节作用中,均表现出对男性的影响大于对女性的影响,其影响大小随着年龄的增加而呈减弱趋势。  相似文献   

间歇低氧运动对胰岛素抵抗大鼠体成分及血脂指标的影响     

李旭武  翁锡全  林文弢 《广州体育学院学报》2014,(4):93-96

目的:探讨间歇低氧运动对胰岛素抵抗大鼠体成分及血脂指标的影响。方法:将高糖高脂膳食建模成功的48只胰岛素抵抗大鼠随机均分为常氧安静组、低氧安静组、常氧运动组和间歇低氧运动组,每组12只。每天进行1h跑速为25m/min的跑台运动,间歇低氧暴露为4h/d(14.5%O2),7d/w。干预4周末测量各组大鼠体成分及血清TG、TC、HDL-C、LDL-C浓度。结果:与常氧安静组比较,间歇低氧安静组、常氧运动组和间歇低氧运动组大鼠体重、肾周脂肪及附睾脂肪重量均出现显著性或极显著性下降(P0.05,P0.01),并以间歇低氧运动组下降最多,而股四头肌及腓肠肌虽有下降,但无统计学意义(P0.05),同时,血清脂代谢指标TG、TC和LDL-C均出现显著或极显著性低于常氧安静组(P0.05,P0.01),而HDL-C则极显著性高于常氧安静组(P0.01),且以间歇低氧运动组大鼠的效果最佳。结论:间歇低氧运动可以改善胰岛素抵抗大鼠体成分和血脂代谢。  相似文献   

Epidemiology of injuries in First Division Spanish football     

Javier Noya Salces  Pedro M. Gómez-Carmona  Diego Moliner-Urdiales  Manuel Sillero-Quintana 《Journal of sports sciences》2014,32(13):1263-1270

Abstract

The aim was to examine the injuries sustained by Spanish football players in the First Division and to compare injury-related variables in the context of both competition and training. The injury data were prospectively collected from 16 teams (427 players) using a specific web-based survey during the 2008/2009 season. A total of 1293 injuries were identified (145 were recurring injuries). The overall injury incidence was 5.65 injuries per 1000 h of exposure. Injuries were much more common during competition than during training (43.53 vs. 3.55 injuries per 1000 h of exposure, P < 0.05). Most of the injuries (89.6%) involved the lower extremities, and overuse (65.7%) was the main cause. Muscle and tendon injuries were the most common types of injury (53.8%) among the players. The incidence of training injuries was greater during the pre-season and tended to decrease throughout the season, while the incidence of competition injuries increased throughout the season (all P < 0.05). In conclusion, the results of this study suggest the need for injury prevention protocols in the First Division of the Spanish Football League to reduce the number of overuse injuries in the muscles and tendons in the lower extremities. In addition, special attention should be paid during the pre-season and the competitive phase II (the last four months of the season) in order to prevent training and competition injuries, respectively.  相似文献   

低氧训练过程中大鼠体重及能量代谢的变化   总被引：1，自引：0，他引：1  

黄徐根  冯连世  徐建方  路瑛丽 《体育科学》2007,27(10):61-68,96

目的：研究低氧训练过程中大鼠体重、体成分、能量摄入及静息代谢率的变化，初步探讨低氧训练过程中大鼠体重变化与能量代谢变化间关系。方法：经过适应性训练筛选出的50只SD大鼠平均分为5组，保证每组大鼠体重基本一致，随机分为常氧安静组、常氧限食组、常氧训练组、低氧安静组、低氧训练组。训练组大鼠采用水平动物跑台进行耐力训练6周。试验期间每周称量大鼠体重，每3天称量一次大鼠食物摄入量。试验前、试验1周、3周、5周末测定大鼠静息代谢率，试验后处死大鼠并剥离其肾周、腹股沟脂肪及腓肠肌，称量其重量。结果：低氧训练组大鼠体重增幅除在第6周末与常氧训练组无显著性差异外，均显著性低于其他试验组，试验前3周其体重出现负增长。试验后低氧训练组大鼠肾周及腹股沟脂肪总含量显著低于其他试验组，而腓肠肌重量与其他组无显著性差异。低氧训练组大鼠试验期间总食物摄入量较其他各组大鼠低，尤其在前3周。低氧训练组大鼠静息代谢率先上升而后逐渐下降，至试验3周末时仍高于试验前值，试验5周末时降至低于试验前值（差异不显著），而除低氧安静组外的其他组大鼠静息代谢率则持续下降，至试验5周末时均显著性低于试验前水平。结论：从减缓体重增加幅度及对体成分的影响角度看，低氧训练减体重的效果优于限制饮食、耐力训练及低氧暴露。低氧训练过程中食物摄入量减少及静息代谢率增加可能是大鼠体重增长减缓的原因。  相似文献   

肥胖儿童少年血脂、红细胞膜脂及PS外翻的研究     

赖爱萍 《浙江体育科学》2011,33(4)

目的：通过对肥胖儿童少年血脂及红细胞膜脂及磷脂酰丝氨酸（PS）外翻的研究,探讨肥胖对儿童少年脂代谢的影响,为早期监测儿童少年脂代谢紊乱提供理论依据。方法：64名肥胖儿童少年按体脂百分比分为轻度、中度和重度3组,测定其血脂六项、红细胞膜胆固醇、PS外翻量及膜Na＋K＋-ATPase和Ca2＋Mg2＋-ATPase活性。结果：①肥胖儿童少年的TC水平已超过参考标准的理想水平;②肥胖儿童少年血TG与BMI及WC、WHR明显正相关,其中和前两项指标显著性P≤0.01;③轻度肥胖组PS外翻量与其他两组肥胖者之间存在显著性差异（P≤0.05）,HDL仅在轻度肥胖者和重度肥胖者之间存在显著性差异。结论：肥胖儿童少年血脂出现紊乱的潜在可能,PS外翻异常可能比血脂指标更早表现出来,因此对儿童少年肥胖发展的预测和预防可能会有更大的价值。  相似文献