Physical activity and nutrition guidelines to help with the fight against COVID-19     

Kayvan Khoramipour  Aref Basereh  Amirhoseein Ahmadi Hekmatikar  Lindy Castell  Ruheea Taskin Ruhee 《Journal of sports sciences》2021,39(1):101-107

ABSTRACT

As the world is witnessing the epidemic of coronavirus disease 2019, emerging genetics and clinical pieces of evidence suggest a similar immunopathology to those of severe acute respiratory syndrome and Middle East respiratory syndrome. Staying at home to prevent the spread of the virus and consequently being largely inactive is associated with unintended consequences. These can actually enhance the infection risk and exacerbate poor health conditions including impaired immune function. Physical activity is a feasible way of improving health, particularly physical and mental health in a time of social isolation. However, people with certain health conditions in these circumstances may need a special physical activity programme in addition to any exercise they may already be performing via online programmes. This review aims to provide practical guidelines during the COVID-19 quarantine period. We suggest performing aerobic, resistance training, respiratory muscle training and yoga in the healthy, and in those with upper respiratory tract illness, patients with lower respiratory tract illness should be restricted to respiratory muscle training and yoga. In addition, vitamins D and C, omega-3 fatty acids, and regular consumption of fruit and vegetables might be considered as nutritional aids to support the immune system in those affected by COVID-19.  相似文献   

Fatigue increases ankle sprain risk in badminton players: A biomechanical study     

Alexis Herbaut  Julien Delannoy 《Journal of sports sciences》2020,38(13):1560-1565

ABSTRACT

Ankle sprains are the most common injury in regular badminton players and usually occur at the end of a match or training. The purpose of the present study was to examine the influence of fatigue produced by badminton practice on the lower limb biomechanics of badminton players. It was hypothesized that fatigue induces ankle kinematic and lower leg muscle activity changes which may increase the risk of ankle sprain. Ankle kinematics, ankle kinetics and muscles activities of 17 regular badminton players were recorded during lateral jumps before and after an intense badminton practice session. Post-fatigue, ankle inversion at foot strike and peak ankle inversion increased (+2.6°, p = 0.003 and +2.5°, p = 0.005, respectively). EMG pre-activation within 100 ms before foot landing significantly decreased after fatigue for soleus (?23.4%, p = 0.031), gastrocnemius lateralis (?12.2%, p = 0.035), gastrocnemius medialis (?23.3%, p = 0.047) and peroneus brevis (?17.4%, p = 0.036). These results demonstrate impaired biomechanics of badminton players when fatigue increases, which may cause a greater risk of experiencing an ankle sprain injury.  相似文献   

一类二元非乘积型Meyer-knig-Zeller概率算子的饱和定理     

刘生贵 《嘉应学院学报》2011,(11):10-14

借助二元抛物线引理,探讨一类二元非乘积型Meyer-knig and Zeller概率算子的饱和性,得到了一个点态饱和定理.  相似文献   

Tribute to Dr Jacques Rogge: muscle activity and fatigue during hiking in Olympic dinghy sailing     

Jan G. Bourgois  Jasmien Dumortier  Margot Callewaert  Bert Celie  Carlo Capelli  Gisela Sjøgaard 《European Journal of Sport Science》2017,17(5):611-620

‘A tribute to Dr J. Rogge’ aims to systematically review muscle activity and muscle fatigue during sustained submaximal quasi-isometric knee extension exercise (hiking) related to Olympic dinghy sailing as a tribute to Dr Rogge’s merits in the world of sports. Dr Jacques Rogge is not only the former President of the International Olympic Committee, he was also an orthopaedic surgeon and a keen sailor, competing at three Olympic Games. In 1972, in fulfilment of the requirements for the degree of Master in Sports Medicine, he was the first who studied a sailors’ muscle activity by means of invasive needle electromyography (EMG) during a specific sailing technique (hiking) on a self-constructed sailing ergometer. Hiking is a bilateral and multi-joint submaximal quasi-isometric movement which dinghy sailors use to optimize boat speed and to prevent the boat from capsizing. Large stresses are generated in the anterior muscles that cross the knee and hip joint, mainly employing the quadriceps at an intensity of 30–40% maximal voluntary contraction (MVC), sometimes exceeding 100% MVC. Better sailing level is partially determined by a lower rate of neuromuscular fatigue during hiking and for ≈60% predicted by a higher maximal isometric quadriceps strength. Although useful in exercise testing, prediction of hiking endurance capacity based on the changes in surface EMG in thigh and trunk muscles during a hiking maintenance task is not reliable. This could probably be explained by the varying exercise intensity and joint angles, and the great number of muscles and joints involved in hiking.

Highlights

• Dr Jacques Rogge, former president of the International Olympic Committee and Olympic Finn sailor, was the first to study muscle activity during sailing using invasive needle EMG to obtain his Master degree in Sports Medicine at the Ghent University.

• Hiking is a critical bilateral and multi-joint movement during dinghy racing, accounting for >60% of the total upwind leg time. Hiking generates large stresses in the anterior muscles that cross the knee and hip joint.

• Hiking is considered as a quasi-isometric bilateral knee extension exercise. Muscle activity measurements during sailing, recorded by means of EMG, show a mean contraction intensity of 30-40% maximal voluntary contraction with peaks exceeding 100%.

• Hiking performance is strongly related to the development of neuromuscular fatigue in the quadriceps muscle. Since maximal strength is an important determinant of neuromuscular fatigue during hiking, combined strength and endurance training should be incorporated in the training program of dinghy sailors.

  相似文献   

Nrf2在有氧运动训练中对小鼠骨骼肌抗氧化能力的作用     

何诗依  张缨 《北京体育大学学报》2017,40(12):50-54

摘要：目的：Nrf2是机体氧化还原平衡的主要调节因子，本研究试图探讨Nrf2在有氧运动训练中对小鼠骨骼肌抗氧化能力的作用。方法：8周龄野生C57BL/6J小鼠和Nrf2敲除小鼠40只，雌雄各半。进一步各为安静组和运动组，每组10只，共4组：分别为野生安静组（WC），野生运动组（WE），敲除安静组（KC）和敲除运动组（KE）。运动组进行4周运动强度为70%VO2max跑速的跑台运动，每周运动6 d，每天运动1 h。运动组最后一次运动后休息48 h脱颈处死，取小鼠后腿骨骼肌。RT-PCR测量Nrf2及Nrf2介导的抗氧化基因mRNA表达量；Western blot法测定骨骼肌Nrf2及抗氧化蛋白含量； GSH试剂盒测量GSH/GSSG比值。结果：1）在安静情况下，KC组和WC组相比，骨骼肌中GSR、NQO1、GCLc、GPX、HO-1和SOD2这6个抗氧化蛋白表达以及GSH/GSSG值没有显著性改变。 2）4周有氧运动训练之后，Nrf2敲除运动组的大部分抗氧化蛋白（CAT, NQO1-1, GCLc, HO-1 and SOD2）和GSH/GSSG值都要显著低于野生运动组。结论：4周70%VO2max强度的有氧运动训练，增加了成年Nrf2敲除和野生鼠骨骼肌抗氧化蛋白表达量和GSH/GSSG比值的差异，而在无训练安静情况下在两种鼠中这些指标的差异不大。说明Nrf2对有氧运动训练中骨骼肌的抗氧化反应起着非常重要的作用。  相似文献   

基于SWMM的地表径流量与城市下垫面和降雨特征关系的空间分析——以中国科学院大学雁栖湖校区为例     

罗英杰  张娜  李琪  王昕  景永才  乐荣武 《中国科学院大学学报》2020,37(1):27-38

以中国科学院大学雁栖湖校区为例，用城市雨洪管理模型（SWMM）模拟2016-2017年48场降雨事件中所有子汇水小区的径流过程；在验证可靠的基础上，探讨径流量空间分布与降雨和下垫面的关系，是开展防汛工作的重要基础。结果表明，径流量高值区多位于沥青小区，而低值区多位于绿地小区。沥青最易产流，绿地最不易产流。砌砖易产生中等量级的径流，混凝土较砌砖更易产流，但二者在不同降雨事件下的产流规律相似。沥青小区和砌砖小区的地表径流量均与坡度呈极显著或显著线性正相关关系。对沥青-砌砖和沥青-绿地小区，将非渗透面积比例（PIC）降至60%可明显控制其暴雨和大雨径流。要明显控制大暴雨径流，可将沥青-绿地小区的PIC降至30%以下；但降低PIC对沥青-砌砖小区大暴雨径流的控制作用不明显。研究结果可为海绵城市建设和城市内涝防洪提供理论依据和决策建议。  相似文献   

基于任务要求的海警船船型论证     

赵瑞嘉  谢新连  李猛  魏照坤 《上海海事大学学报》2017,38(1):16-20

为使海警船性能满足新形势的要求,建立以满足任务要求且使单位投资与使用成本最低为目标的海警船船型论证模型.利用回归分析方法找到船舶主尺度的变化规律和船舶主要要素对投资与使用成本的影响规律.利用该模型可以实现对船舶主尺度的优化.以一艘设计排水量为4 500 t的海警船为例进行船型论证,并将论证结果与国外类似船舶进行比较,分析差异及差异产生的原因.结果验证了该模型的合理性与实用性,表明该模型能够为海警船的论证选型提供决策支持.  相似文献   

矩形截面纤维流场压降及细颗粒扩散捕集效率     

黄浩凯  赵海波 《中国科学院大学学报》2017,34(2):210-217

采用格子波尔兹曼气固两相流模型模拟扩散机制下矩形纤维捕集颗粒过程，研究纤维周围流场压降和扩散捕集效率随不同纤维布置方式的变化规律。把模拟得到的值（系统压降与捕集效率）与相同体积分数的圆柱纤维所对应的理论值相比，得到相应比例系数。分析规律，并采用Levenberg-Marquardt方法对其进行处理，得到相应比例系数的拟合公式。根据已有的圆形纤维压降与扩散效率的理论公式，再结合求得的拟合公式，对不同工况下的矩形纤维系统压降和扩散捕集效率进行计算。分析结果发现：矩形纤维系统压降与放置角度和长宽比均相关；而扩散捕集效率与长宽比成正比，与放置角度基本无关。  相似文献   

日本近代两次对外战争对学校体育的影响     

刘春燕  谭华  季浏 《北京体育大学学报》2016,39(8):102-108

摘要：甲午战争和日俄战争是导致近代中日两国历史剧变的两次重要战争，对中日两国社会和学校体育的发展都产生了巨大影响。20世纪90年代以来，日本学术界曾盛行甲午战争“偶发论”，为驳此论，本文采用文献资料法，依据大量日文史料梳理日本学校体育随两次对外侵略战争而发生重大转变的过程，分析两次战争对日本学校体育的重要影响，以及学校体育为战争胜利而发挥的特殊作用，从体育角度证实了甲午战争是日本长期准备并精心谋划的。认为甲午战争和日俄战争是日本近代学校体育的重大转折点，学校体育从此由培养现代化人才的途径转变为为扩军备战服务的工具，并对20世纪日本乃至中国的学校体育都产生了深远影响。学校体育作为甲午、日俄战前日本精心备战的环节之一，为日本两次获胜有效发挥了军事预备教育的作用，但也影响了自身的正常发展，留下了深刻的历史教训。  相似文献   

发电企业防范知识型员工流失的管理策略     

李绍丽 《洛阳师范学院学报》2006,25(5):149-152

随着国内电力市场化改革的逐步深入,知识型员工作为掌握专业技术知识的人才,日益成为企业间争夺的对象.本文探讨了知识型员工的特点,并由此入手分析了知识型员工流失的原因,提出了一套变管理为服务的制度以及防范该类员工流失可能对企业造成损失的措施.  相似文献