从知识人的视角看教师角色变迁     

李素立 《河南师范大学学报(哲学社会科学版)》2007,34(3):217-219

在漫长的历史中,教师作为知识人,其角色发生了重大的转变:从“知识的传授者”转变为“开发者”、“行动研究者”和“激励者、组织者和指导者”。这一角色变迁的实质是师生逐渐摆脱教育过程中的“非人”地位,发挥其作为教育主体的自主性和创造性的过程。  相似文献   

转型期高校图书馆存在的问题与对策     

郭玮 《山东电大学报》2003,(1):57-58

当前，面临转型期的图书馆事业存在着一系列的问题，解决的途径和对策需要我们从技术、经济、人才三方面进行认真研究。  相似文献   

DSⅡ方程的Darboux变换及其孤立子解     

唐国雄 《黄冈师范学院学报》1992,(3)

本文找到了DSⅡ方程的Darboux变换,利用所给出的Darboux变换求得了DS Ⅱ方程的一簇解。还利用[1]中给出的规范变换自然地得到(2+1)维Heisenberg链的无限多个解。  相似文献   

Specific tackling situations affect the biomechanical demands experienced by rugby union players     

Elena Seminati  Dario Cazzola  Ezio Preatoni  Grant Trewartha 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(1):58-75

Tackling in Rugby Union is an open skill which can involve high-speed collisions and is the match event associated with the greatest proportion of injuries. This study aimed to analyse the biomechanics of rugby tackling under three conditions: from a stationary position, with dominant and non-dominant shoulder, and moving forward, with dominant shoulder. A specially devised contact simulator, a 50-kg punch bag instrumented with pressure sensors, was translated towards the tackler (n = 15) to evaluate the effect of laterality and tackling approach on the external loads absorbed by the tackler, on head and trunk motion, and on trunk muscle activities. Peak impact force was substantially higher in the stationary dominant (2.84 ± 0.74 kN) than in the stationary non-dominant condition (2.44 ± 0.64 kN), but lower than in the moving condition (3.40 ± 0.86 kN). Muscle activation started on average 300 ms before impact, with higher activation for impact-side trapezius and non-impact-side erector spinae and gluteus maximus muscles. Players’ technique for non-dominant-side tackles was less compliant with current coaching recommendations in terms of cervical motion (more neck flexion and lateral bending in the stationary non-dominant condition) and players could benefit from specific coaching focus on non-dominant-side tackles.  相似文献   

我国男生引体向上“零”分探因:基于三角互证的研究策略     

何素艳  石岩 《武汉体育学院学报》2019,53(10):81-87

我国多数男生引体向上得"零"分，使上肢力量测评出现"地板效应"。采用量化研究和质性研究两种范式提高研究效度。量化研究对学生体质与健康调研数据和监测数据进行方差分析、多重比较和回归分析，结果表明：（1）每5~10年，男生的握力、体重、身高、BMI、引体向上均值差异显著；（2）年龄、握力、体重、身高、BMI分别显著预测引体向上成绩，体重和握力是影响我国男生引体向上成绩的主要影响因素。质性研究结果表明，引体向上"零"分主要有四个方面的原因：体重增长难挡，力量增长受限，个体认知偏差，社会支持薄弱。结论：我国男生引体向上"零"分的首要原因是体重增长较快，其次，主要肌群绝对力量和耐力增长不足，男生对引体向上的认知有偏差，学校、家长、社会支持较弱；借助政策控制体重、发展肌力、完善测评标准、促进男生积极练习引体向上十分重要。  相似文献   

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   

公共体育场馆功能改造之理论逻辑与现实困境--以洪山体育中心为例     

陈元欣  陈磊  刘恒  郑芒芒 《上海体育学院学报》2020,(5):37-46

运用实地考察法、问卷调查法、主成分分析法等,对公共体育场馆功能改造的理论逻辑与现实困境进行剖析。认为消费者需求与公共体育场馆功能之间存在相互作用的理论逻辑,据此提出基于消费需求识别的公共体育场馆功能选择路径,以洪山体育中心为例进行实证分析。同时,对当前公共体育场馆功能改造在土地利用、消费场景营造、利益主体参与机制和改造程序等方面面临的现实困境进行总结。提出:创新用地政策,鼓励公共体育场馆进行功能改造;加强公共体育场馆消费场景营造;健全利益主体参与机制;建立健全多部门合作的公共体育场馆功能改造工作机制。  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   

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