Joint work is not shifted proximally after a long run in rearfoot strike runners     

Jake A. Melaro  Allison H. Gruber 《Journal of sports sciences》2021,39(1):78-83

ABSTRACT

Distal-to-proximal redistribution of joint work occurs following exhaustive running in recreational but not competitive runners but the influence of a submaximal run on joint work is unknown. The purpose of this study was to assess if a long submaximal run produces a distal-to-proximal redistribution of positive joint work in well-trained runners. Thirteen rearfoot striking male runners (weekly distance: 72.6 ± 21.2 km) completed five running trials while three-dimensional kinematic and ground reaction force data were collected before and after a long submaximal treadmill run (19 ± 6 km). Joint kinetics were calculated from these data and percent contributions of joint work relative to total lower limb joint work were computed. Moderate reductions in absolute negative ankle work (p = 0.045, Cohen’s d = 0.31), peak plantarflexor torque (p = 0.004, d = 0.34) and, peak negative ankle power (p = 0.005, d = 0.32) were observed following the long run. Positive ankle, knee and hip joint work were unchanged (p < 0.05) following the long run. These findings suggest no proximal shift in positive joint work in well-trained runners after a prolonged run. Runner population, running pace, distance, and relative intensity should be considered when examining changes in joint work following prolonged running.  相似文献   

两种大强度间歇训练对优秀公路自行车运动员有氧能力的影响          下载免费PDF全文

屈成刚  唐一丹 《体育科研》2019,(1):64-71

目的：比较两种大强度间歇训练手段对优秀自行车运动员有氧运动能力的影响。方法：将15名备战全国“十三运”的云南省自行车队男子运动员随机分为3组， S组训练方案采用SIT/耐力训练， H组训练方案采用HIIT/耐力训练， C组为对照组，进行传统耐力性训练；训练持续3周。训练前后进行递增负荷测试和有氧运动能力测试，测试指标包括最大摄氧量绝对值（VO2max）、最大摄氧量相对值（VO2max/kg）、每分通气量（VE）、最大心率（HRmax），并通过公式计算每搏输出量（SV），以及测试递增负荷后即刻血乳酸（BLA）、最大有氧功率（P）和40 km个人计时成绩进行了测试。结果：（1）3周训练后，S组运动员VE、HRmax、SV、VO2max、VO2max/kg、P和ITT40km均较训练前有显著性提高（P＜0.05）；H组运动员VE、VO2max/kg、ITT40km较训练前有显著性增加（P＜0.05），BLA有显著性的下降（P＜0.05）。（2）S组运动员ΔVE、ΔHRmax、ΔSV、ΔVO2max、ΔVO2max/kg、ΔBLA、ΔITT40km显著提升（P＜0.05），且优于其余两组；H组仅ΔITT40km存在明显提升（P＜0.05）。结论：间歇训练结合耐力训练对优秀公路自行车运动员的呼吸系统、有氧供能系统可产生积极的影响；而且，SIT结合耐力训练较HIIT结合耐力训练或传统耐力训练更能提高公路自行车运动员的有氧代谢能力和有氧运动能力，训练效果更佳。  相似文献   

Effect of different loading conditions on running mechanics at different velocities     

Germán Carretero-Navarro  Doménico Cherubini  Wolfgang Taube 《European Journal of Sport Science》2019,19(5):595-602

Weighted vests are widely used to improve running economy and performance. However, it is not well-studied how running mechanics are adapted to counteract the higher peak vertical ground reaction forces (Fpeak) while running with such a device. Therefore, the present study aimed to investigate the effects of different loading conditions on running mechanics at different velocities. Thirteen subjects participated in two separate sessions one week apart. In the first session, maximal aerobic speed (MAS) was determined through a maximal incremental running test while in the second session, they were instructed to run during one minute under different loading (0%, +10% and +20% of body mass [BM]) and velocity (60%, 80% and 100% of MAS) conditions in a random order. Spatiotemporal data were recorded and then running mechanics modelled using the spring-mass model. The main results indicated that vertical and leg stiffness (Kvert and Kleg, respectively) were increased (P?P?>?.05) when load was changed. At the same time, alterations of the running kinematics were observed such as longer contact times, reduced flight times, stride frequencies and step lengths, as well as an increase of the centre of mass dynamics. Based on these results it is assumed that runners maintain a certain stiffness level for each velocity despite different loading conditions. As a consequence, Fpeak increases and this probably causes spatiotemporal adjustments in the movement kinematics.  相似文献   

From the body to the city: participatory action research with social cartography for transformative education and global citizenship     

Monique Leivas 《Educational Action Research》2019,27(1):40-56

ABSTRACT

In times of globalization we are facing a crisis of care. The invisibility of relations of domination and oppression against nature, women and girls, as well as the elderly, generate inequalities and structural problems that increase the unsustainability of life on the planet. The uncertainty towards the future, generated by climate change, pollution and scarcity of water resources, is leading us towards war or revolution – a revolution that requires the involvement of the new generations to transform reality and confront contemporary problems. In this sense, it is necessary to educate, raise awareness and empower girls and boys in citizen participation, in overcoming gender inequalities and in the development of fairer and more sustainable practices and behaviours. The participatory action-research experience with social cartography ‘From the Body to the City’, promoted by the Institute of Innovation and Knowledge Management – INGENIO (CSIC-UPV) in collaboration with the primary school CEIP Vicente Gaos of Valencia (Spain), developed together with the students of 4th primary grade, intended to reflect and act collectively on our territories from the principles of transformative education and global citizenship.  相似文献   

全球媒体语境下广州城市形象的传播与建构     

王大可  李本乾 《中国名城》2020,(5):93-98

城市形象是城市竞争力的重要组成部分。依托全球媒体有关广州的报道,对广州城市形象的全球媒体影响力开展实证分析,并从强化政府主导、畅通参与渠道;融入国家战略、提升传播层级;推进科技创新、塑造崭新形象;发展数字产业、夯实传播基础;布局未来传播、增强舆论引导等方面构建提出了增强广州城市形象全球传播能力的对策建议。  相似文献   

银川市社区居民体力活动现状调查与分析     

王慧  谭秋实 《当代体育科技》2020,(8):158-160

目的:调查银川市居民体力活动现状并对其进行分析。方法:采用IPAQ-长卷对银川市社区居民进行调查。结果:高水平体力活动者为55.3%,中等水平者为36%。男性的一周VPA显著高于女性(P<0.05);大专及以上教育程度者TPA、MPA和WPA都显著低于其他教育程度者(P<0.05);85%的居民达到了世卫组织推荐的身体活动量。结论:银川城市居民体力活动水平较高,中等强度体力活动和步行体力活动的比例大;男性在VPA上显著高于女性,但在其他方面与女性无显著差异;受教育程度对体力活动的影响较大;大多数社区居民达到了世卫组织推荐的身体活动量。  相似文献   

哈密市沙漠体育旅游赛事资源开发构想与对策分析     

任婷 《当代体育科技》2020,(12):224-224,226

哈密市沙漠旅游发展的晚,尚属于不成熟期,有不少旅游资源亟待开发,沙漠体育旅游赛事资源就是其中重要一项。哈密市的经济实力较强,旅游资源丰富,在沙漠旅游体育赛事的开发上具有鲜明的代表性,对国内其他城市的沙漠旅游体育赛事的开发有借鉴作用。本文运用实地走访法,以哈密市沙漠旅游体育赛事的开发构想为例,展开调查与研究,找出在开发问题中可能遇到的问题和困难,并提出意见和建议为更好地指导哈密市开展沙漠体育旅游赛事提供现实指导。  相似文献   

海绵城市、城市公园、城市建筑与绿色城市     

曹婷  连之伟  周武忠 《中国名城》2021,(4):8-14

“绿色”作为现代城市主题,将“城市种进大自然”成为由城市建设不当导致生态问题的核心解决策略。依据设计实践和相关案例分析,可提出:(1)海绵城市的核心治理理念和目前建筑能耗相关概念结合,以“削峰填谷”解决环境、城市内涝问题。(2)城市公园设计必须从生态的丰富内涵出发,尊重城市地格,同时注意整个城市的公园联络性,形成城市空间内的自然轴线.。(3)垂直绿化不仅是单一的绿色外观建筑设计形式,还需要和建筑功能空间、理念结合,让自然这个元素由外向内渗透到建筑内部、人居环境、人们健康饮食以及健康生活方式甚至是思想观念,从建筑外观或者城市形象来增添城市与自然的相关性。  相似文献   

Leg amputation side determines performance in curve sprinting: a case study on a Paralympic medalist     

Johannes Funken  Kai Heinrich  Steffen Willwacher  Ralf Müller  Jonas Böcker  Hiroaki Hobara 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(1):75-87

The lower limb kinetics of curve sprinting in amputees are not well described in the literature, particularly with respect to the effect of the side of amputation. This is an issue due to the importance of the knowledge for prosthetic design and classification of athletes. Thus, the aim of this study was to investigate the influence of side of amputation on curve sprinting performance in athletes with a unilateral leg amputation. A three-dimensional motion analysis system (Vicon), four force plates (Kistler) and a modified mathematical human model (ALASKA) were used to compare clockwise and counter clockwise curve sprinting lower limb kinematics and kinetics of a Paralympic medalist with a left-sided knee exarticular amputation. Results reveal that vertical ground reaction force application and total vertical impulse were lower when the affected limb was at the inside of the curve. The unaffected limb showed joint mechanics different to those established for non-amputee athletes and might contribute better to propulsion when being the inside limb. Curve sprinting biomechanics and the ability to attain high radial velocities are directly dependent on the side of amputation relative to the curve direction in a unilateral amputee athlete of highest performance level.  相似文献   

Russians are the fastest and the youngest in the “Comrades Marathon”     

Pantelis T. Nikolaidis 《Journal of sports sciences》2019,37(12):1387-1392

The present retrospective study intended to determine age, performance, the role of nationality and participation trends across calendar years in runners competing in “Comrades Marathon”, the ultra-marathon with the longest tradition and the highest number of finishers worldwide. We analysed 235,467 finishers (40,211 women and 195,256 men) competing between 1994 and 2017. In women and men, Russians were the fastest (12.55 ± 2.03 km/h and 12.24 ± 2.93 km/h, respectively) and Indians the slowest (7.87 ± 0.64 km/h and 7.91 ± 0.60 km/h) (p < 0.001, η2 = 0.053 and η2 = 0.010, small effect size, ES). Also, Russians were the youngest (33.9 ± 4.6 and 36.3 ± 5.9 years, respectively) and Japanese the oldest (49.3 ± 9.6 and 51.4 ± 12.3 years, respectively) (p < 0.001, η2 = 0.011, small ES). Performance improved (r = 0.90 in women and r = 0.92 in men), age of finishers (r = 0.91 in women and r = 0.97 in men), participation (r = 0.92 in women and r = 0.87 in men) and sex difference in age increased (r = 0.71), whereas men-to-women ratio (r = ?0.91) and sex difference in performance (r = ?0.68) decreased across calendar years (p < 0.001). In summary, runners from Russia were the fastest and the youngest in both sexes. The knowledge of the relationship of nationality with performance, age and participation trends of finishers, and changes across calendar years are of practical importance for ultra-runners and coaches working with them.  相似文献