集训对舞龙队女大学生血常规及内皮祖细胞的影响     

孔明涯  任路遥 《体育科技文献通报》2020,(4):156-158

目的:分析舞龙运动对女大学生血常规及内皮祖细胞含量的影响。方法:选取2017级舞龙队女大学生10人为训练组,2017级普通女大学生10人作为对照组。舞龙队女大学生备战比赛进行连续4周,每周3次,每次90min的赛前集训,普通女大学生除日常活动外,没有额外进行任何其他运动队的集训。集训结束后,在受试者都处于空腹状态下对两组受试者进行静脉采血并进行血常规、早期内皮祖细胞和晚期内皮祖细胞的检测。所得数据进行统计学分析。结果:参加舞龙集训的女大学生的血常规指标与普通女大学生的血常规指标无显著差异,早期EPCs和晚期EPCs无显著性差异,但在数值上显示出不同的趋势。结论:参加舞龙集训的女大学生身体处于健康状态。参加舞龙集训有可能增强运动员血管的自我修复能力。  相似文献   

Acute cardiovascular responses to interval exercise: A systematic review and meta-analysis     

Kym Joanne Price  Brett Ashley Gordon  Stephen Richard Bird  Amanda Clare Benson 《Journal of sports sciences》2020,38(9):970-984

ABSTRACT

Interval exercise training is increasingly recommended to improve health and fitness; however, it is not known if cardiovascular risk is different from continuous exercise protocols. This systematic review with meta-analyses assessed the effect of a single bout of interval exercise on cardiovascular responses that indicate risk of cardiac fibrillation and infarction compared to continuous exercise. Electronic databases Medline, CINAHL, Embase, Scopus and Cochrane were searched. Key inclusion criteria were: (1) intervals of the same intensity and duration followed by a recovery period and (2) reporting at least one of blood pressure, heart rate variability, arterial stiffness or function. Cochrane Risk of Bias tool and GRADE approach were used. Meta-analyses found that systolic blood pressure responses to interval exercise did not differ from responses to continuous exercise immediately (MD 8 mmHg [95% CI ?32, 47], p = 0.71) or at 60 min following exercise (MD 0 mmHg [95% CI ?2, 1], p = 0.79). However, reductions in diastolic blood pressure and flow-mediated dilation with interval exercise were observed 10–15 min post-exercise. The available evidence indicates that interval exercise does not convey higher cardiovascular risk than continuous exercise. Further investigation is required to establish the safety of interval exercise for clinical populations.  相似文献   

低负荷加压训练改善自发性高血压大鼠的血压效果及机制研究     

谭朝文  赵彦  俞莹莹  马晓缓  郑玉婵 《体育科学》2020,(3):46-53,63

目的:探究低负荷加压训练对自发性高血压大鼠的降压效果及其作用机制。方法:选取4周龄雄性自发性高血压大鼠,随机分为对照组(高血压安静组)、低负荷训练组、低负荷加压训练组和高负荷训练组。低负荷训练组进行35%~55%1RM递进式低负荷爬梯训练,低负荷加压训练组进行30%~40%血流受限结合35%~55%1RM递进式低负荷爬梯训练,高负荷训练组进行55%~75%1RM递进式高负荷爬梯训练,训练后测定血压、血液中内皮素-1、血管内皮生长因子、一氧化氮合成酶的表达和心肌组织中内皮型一氧化氮合成酶的表达。结果:1)与对照组、高负荷训练组相比,低负荷加压训练组收缩压、舒张压显著下降(P<0.05);与低负荷训练组相比,低负荷加压训练组舒张压显著下降(P<0.05)。2)与对照组相比,低负荷加压训练组血液中内皮素-1表达显著下调(P<0.05),血管内皮生长因子和一氧化氮合成酶表达显著上调(P<0.05);3)与对照组相比,低负荷加压训练组心肌中内皮型一氧化氮合成酶表达显著上调(P<0.05);4)在低负荷加压训练组中,收缩压与内皮素-1呈正相关,相关性分析具有统计学意义(P<0.05);收缩压与一氧化氮合成酶、血管内皮生长因子、内皮型一氧化氮合成酶均呈负相关,相关性分析具有统计学意义(P<0.05)。结论:1)低负荷加压训练降压效果优于高负荷训练;2)低负荷加压训练能够通过下调血液中内皮素-1的表达,上调血液中血管内皮生长因子和一氧化氮合成酶的表达,同时上调心肌中内皮型一氧化氮合成酶表达,改善内皮细胞功能,达到降压的效果。  相似文献   

Combined effects of exposure to hypoxia and cool on walking economy and muscle oxygenation profiles at tibialis anterior     

Masahiro Horiuchi  Yoko Handa-Kirihara  Daijiro Abe  Yoshiyuki Fukuoka 《Journal of sports sciences》2019,37(14):1638-1647

We investigated combined effects of ambient temperature (23°C or 13°C) and fraction of inspired oxygen (21%O₂ or 13%O₂) on energy cost of walking (C_w: J·kg^?1·km^?1) and economical speed (ES). Eighteen healthy young adults (11 males, seven females) walked at seven speeds from 0.67 to 1.67 m s^?1 (four min per stage). Environmental conditions were set; thermoneutral (N: 23°C) with normoxia (N: 21%O₂) = NN; 23°C (N) with hypoxia (H: 13%O₂) = NH; cool (C: 13°C) with 21%O₂ (N) = CN, and 13°C (C) with 13%O₂ (H) = CH. Muscle deoxygenation (HHb) and tissue O₂ saturation (StO₂) were measured at tibialis anterior. We found a significantly slower ES in NH (1.289 ± 0.091 m s^?1) and CH (1.275 ± 0.099 m s^?1) than in NN (1.334 ± 0.112 m s^?1) and CN (1.332 ± 0.104 m s^?1). Changes in HHb and StO₂ were related to the ES. These results suggested that the combined effects (exposure to hypoxia and cool) is nearly equal to exposure to hypoxia and cool individually. Specifically, acute moderate hypoxia slowed the ES by approx. 4%, but acute cool environment did not affect the ES. Further, HHb and StO₂ may partly account for an individual ES.  相似文献   

Effects of periodic carbohydrate ingestion on endurance and cognitive performances during a 40-km cycling time-trial under normobaric hypoxia in well-trained triathletes     

Yi-Hung Liao  Toby Mündel  Yan-Ting Yang  Chen-Chan Wei  Shiow-Chwen Tsai 《Journal of sports sciences》2019,37(16):1805-1815

The purpose of this study was to examine CHO ingestion on a cognitive task using a field-simulated time-trial (TT) under hypoxia in well-trained triathletes. Ten male triathletes (age: 22.1 ± 1.1 years; VO₂max: 59.4 ± 1.4 ml/kg/min) participated in this double-blind/crossover/counter-balanced design study. Participants completed 3 TT trials: 1) normoxic placebo (NPLA; FiO₂ = 20.9%), 2) hypoxic placebo (HPLA; FiO₂ = 16.3%), and 3) hypoxic CHO (HCHO; 6% CHO provided as 2 ml/kg/15 min; FiO₂ = 16.3%). During the TT, physiological responses (SpO₂, HR, RPE, and blood glucose/lactate), cognitive performance, and cerebral haemodynamics were measured. Hypoxia reduced TT performance by ~3.5–4% (p < 0.05), but CHO did not affect TT performance under hypoxia. For the cognitive task, CHO slightly preserved exercise-induced cognitive reaction speed but did not affect response accuracy during hypoxic exercise. However, CHO did not preserve the decreased Hb-Diff (cerebral blood flow, CBF) and increased HHb in the prefrontal lobe (p < 0.05) during hypoxic exercise, and CHO failed to preserve hypoxia-suppressed prefrontal CBF and tissue oxygen saturation. In conclusion, the present study demonstrates that CHO is effective in sustaining reaction speed for a cognitive task but not promoting TT performance during hypoxic exercise, which would be important for strategy-/decision-making when athletes compete at moderate high-altitude.  相似文献   

中外历史比较札记六则     

葛志毅 《大连大学学报》2007,28(5):1-10

在世界历史的发展中,往往会在不同的民族间发生些彼此相近似的社会现象。一方面可能是在相近似的社会历史条件下,人们可能采用相类似的应对方法所致;另一方面则可能是不同民族间在文化上相互借鉴的结果;也有可能是偶然如此,无从考察说明其联系。但世界历史的整体性、相互关联性,从来是无可否认的,更有些同中有异,异中见同的历史现象耐人寻味。通过比较的方法研究这类现象,对人们认识历史应该有所启发。这篇文章以比较的方法,指出领土主权、血缘原则与地缘原则、盟约仪式、采地与永佃权、城邦制度与专制制度、法律传统与专制制度等政治法权概念在中外历史上反映出的不同意义,以及与之相关的中外历史发展中的不同社会文化特征,同时也借以追溯相关制度在中外历史上的各自渊源与差别之所在。  相似文献   

面向智能车的新型电子液压制动系统设计与分析          下载免费PDF全文

查云飞  孟宪锋郑寻侯乃仁郭炎荣 《福建工程学院学报》2021,(4):335-341

针对传统液压制动系统应用场景受限的问题,面向智能车设计新型电子液压制动系统,由车辆配备的智能驾驶系统将制动信号传递给制动系统,制动系统由助力制动子系统和备份制动子系统组成,两系统之间通过单向导通梭阀完成解耦。利用系统硬件在环实验,分析电子液压制动系统的动态特性。实验结果表明:影响电子液压制动系统建压响应性与精度的因素众多,为使得系统可以快速响应,应确保整车制动管路排气良好,尽量避免使用制动软管?同时,不宜长时间进行高压力保压工况,避免电机及电机驱动器过热从而降低制动效能。  相似文献   

SPOC整合翻转课堂教学模式在输血与输血技术课程中的应用和效果评价     

李宗吉  丁淑琴 《科教导刊》2021,(2):146-147,182

探索解决输血与输血技术课程中知识点复杂、实践性强、教学效果不理想等问题的教学新模式,以期提升学生将医学理论知识和临床技能结合用于分析解决临床实际问题的能力.  相似文献   

小汽车使用外部性内部化效果分析     

张香平 《中国软科学》2007,(8):156-160

本文从交通运输方式外部性的概念出发阐述了外部性内部化的意义,利用小汽车出行需求曲线、小汽车出行的平均成本曲线以及小汽车使用的社会边际成本曲线,以小汽车使用的社会边际成本为参考依据,分三种情况对外部成本内部化效果进行了经济分析。另外,利用经济学原理,分析了小汽车外部成本内部化的替代效应与收入效应。结论表明,由于存在着收入效应和替代效应,对小汽车使用外部成本内部化,有利于城市客运交通系统中各种运输方式间的公平竞争,真正体现和实现公交优先政策。  相似文献   

Oxidant and antioxidant status in vegetarians and fish eaters     

K. Poornima  M. Cariappa  K. Asha  H. P. Kedilaya  M. Nandini 《Indian journal of clinical biochemistry : IJCB》2003,18(2):197-205

An adequate antioxidant reserve which is usually present in a vegetarian diet is associated with higher life expectancy. On the other hand habitual consumption of fish is associated with lower risk of cardiovascular diseases which is attributed to the polyunsaturated fatty acids (PUFA) present in it. However the PUFA are readily susceptible to oxidation leading to the formation of free radicals which is known to be involved in the causation of several diseases. The oxidant-antioxidant status of 23 vegetarians and 22 fish eaters was studied by determining the plasma lipid peroxides measured as malondialdehyde (MDA) and the antioxidants, viz. glutathione (GSH), ascorbic acid, ceruloplasmin and uric acid. Results show that the ascorbic acid values were significantly higher in vegetarians. In addition, MDA correlated negatively with ascorbic acid only in vegetarians. However, correlation of MDA with glutathione showed a significant negative correlation only in fish eaters. There was no statistically significant difference in the MDA, GSH, ceruloplasmin and uric acid levels. The mechanism behind these findings are not clear and needs to be explored.  相似文献