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   

一次性塑料快餐盒盖成型工艺分析及逆向设计     

吕淑艳 《包头职业技术学院学报》2020,(1):1-2,15

采用逆向思维方法,详细分析了一次性快餐盒盖的成型工艺,并对其结构进行改进设计。为那些以实物为制造基础的产品的设计提供了借鉴,在缩短产品开发周期,提高经济效益方面,起着重要作用。  相似文献   

高职院校农业类专业课程教学改革的实践与反思     

哈满林  李萍  黄守敏 《安徽职业技术学院学报》2020,(1):88-91

文章针对高职农业类专业学生类型结构趋向多元化、教学内容与生产实际相脱离、教学团队的结构亟待优化、教学组织形式亟待改进等突出问题,通过对岗位职业能力、工作任务进行梳理,重构教学内容,改进教学方法,组建结构化教学团队,会同行业专家共同开发活页式教材,使教学过程可控、课堂活力提升,显著改善了教学效果。  相似文献   

“体教结合”视角下体育运动学校“三集中”办学办训模式发展的困境及其对策——以徐汇区青少年体育运动学校为例          下载免费PDF全文

郑昕波  王春秀 《体育科研》2019,(2):49-55

当前在我国培养高水平竞技体育人才的多种方式中，“体教结合”的“三集中”（集中住、集中学、集中训）办学模式占据着独特的优势和特殊的地位。然而，伴随着高考制度的改革，上海市相关人口政策的相继出台，以及家长对子女未来职业选择的多元化趋势等，青少年体育运动学校的“三集中”式办学的主要矛盾凸显。以徐汇区青少年体育运动学校/徐汇位育体校为研究对象，分析学校“体教结合”的“三集中”办学模式发展的瓶颈问题，并对其产生的原因进行解析，进而提出解决“三集中”办学模式发展困境的若干对策及建议。  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   

Idea generation in biomedical engineering courses using Design Heuristics     

Jin Woo Lee  Anastasia Ostrowski  Aileen Huang-Saad  Colleen M. Seifert 《European Journal of Engineering Education》2019,44(3):360-378

ABSTRACT

With increasing demand for improved medical equipment and healthcare, next-generation biomedical engineers need strong design skills. Equipping biomedical engineering students with tools for idea generation and development can increase student design success. Design Heuristics are an ideation tool developed through empirical studies of product designs. While identified in the mechanical engineering space, Design Heuristics may be applicable in biomedical engineering design. In our study, we implemented a Design Heuristics session during upper-level undergraduate and first-year graduate biomedical engineering design courses. We examined the applicability of Design Heuristics within individual and team concept generation contexts. The findings demonstrated that biomedical engineering students were able to use Design Heuristics to generate multiple concepts, and that initial concepts produced using Design Heuristics were carried over into final team design. The results support the applicability of Design Heuristics to student idea generation in biomedical engineering design.  相似文献   

指向武术核心素养的中小学武术有效教学策略与方法设计     

柴广新  孙有平 《武汉体育学院学报》2020,54(4):87-92

为了有效促进学生武术核心素养的培育,针对我国武术教学中存在套路内容“繁难”、教法单一、重“形”轻“击”、重知识灌输,轻自主性培养、重教师的“教”,轻学生的“学”“学生不喜欢武术课”等一系列问题,提出了有效促进武术认知、武术运动能力、武术人格培育的原则,基于此原则,对“化难为易”策略、“化浅为深”策略、“化无趣为有趣”策略、“化技术为实践”策略、“知新温故”等策略进行了具体探索性设计,并对上述策略的具体实施方法进行了阐述,为中小学武术教学改革提供现实指导。  相似文献   

The biomechanical characteristics of high-performance endurance running     

Stephen J. Preece  Christopher Bramah  Duncan Mason 《European Journal of Sport Science》2019,19(6):784-792

The biomechanical profile of high-level endurance runners may represent a useful model that could be used for developing training programmes designed to improve running style. This study, therefore, sought to compare the biomechanical characteristics of high-performance and recreational runners. Kinematic and kinetic measurements were taken during overground running from a cohort of 14 high-performance (8 male) and 14 recreational (8 male) runners, at four speeds ranging from 3.3 to 5.6?m?s^?1. Two-way ANOVA analysis was then used to explore group and speed effects and principal component analysis used to explore the interdependence of the tested variables. The data showed the high-performance runners to have a gait style characterised by an increased vertical velocity of the centre of mass and a flight time that was 11% longer than the recreational group. The high-performance group were also observed to adopt a forefoot strike pattern, to contact the ground with their foot closer to their body and to have a larger ankle moment. Importantly, although observed group differences were mostly independent of speed, the tested variables showed a high degree of interdependence suggesting an underlying unitary phenomenon. This is the first study to compare high-performance and recreational runners across a full range of kinematic and kinetic variables. The results suggest that high-performance runners maintain stride length with a prolonged aerial phase, rather than by landing with a more extended knee. These findings motivate future intervention studies that should investigate whether recreational runners could benefit from instruction to decrease shank inclination at foot contact.  相似文献   

A qualitative investigation of design knowledge reuse in project-based mechanical design courses     

Dónal P. Holland  Conor J. Walsh 《European Journal of Engineering Education》2019,44(1-2):137-152

ABSTRACT

The interpretation and reuse of previous design solutions, or precedents, is central to design. This paper describes qualitative research conducted over three years at two institutions, aimed at investigating the role of design knowledge re-use in project-based mechanical design courses. Research data were collected through participant observation, student interviews, anonymous questionnaires, and website analytics. The paper identifies challenges that must be addressed in order to support novice engineers in rehearsing the types of knowledge required to successfully reason about and engage with design precedents. Two categories of design precedents are identified: concept precedents and detail precedents. Providing students with access to the latter is identified as a particular challenge, as is providing students with access to engineering communities of practice. Approaches to addressing these challenges are discussed.  相似文献   

Data Visualization as Participatory Research: A Model for Digital Collections to Inspire User-Driven Research     

A. Miller 《Journal of Web Librarianship》2019,13(2):127-155

The emerging creative practices of digital collections are increasing in prominence thanks to the access to, and appeal of, data visualizations. Interactive data visualizations, such as a map, timeline, chart, graph, or artist’s rendering of data, enable users to pursue their own research interests within a collection and participate in new areas of research. Use of these data visualizations enhances the scope of the collection and enables a modern and diverse thematic collection to emerge. This article considers the question: Does the addition of data visualizations affect how users participate with a research collection? Impacts on collection development, application of user-centered design, and analysis of users’ exploratory strategies are discussed. Examples of data visualizations used in digital humanities projects and digital collections are presented as case studies.  相似文献