Are gait characteristics and ground reaction forces related to energy cost of running in elite Kenyan runners?     

J. Santos-Concejero  N. Tam  D. R. Coetzee  J. Oliván  T. D. Noakes  R. Tucker 《Journal of sports sciences》2017,35(6):531-538

The aim of this study was to determine whether gait cycle characteristics are associated with running economy in elite Kenyan runners. Fifteen elite Kenyan male runners completed two constant-speed running sets on a treadmill (12 km ·h^?1 and 20 km ·h^?1). VO₂ and respiratory exchange ratio values were measured to calculate steady-state oxygen and energy cost of running. Gait cycle characteristics and ground contact forces were measured at each speed. Oxygen cost of running at different velocities was 192.2 ± 14.7 ml· kg^?1· km^?1 at 12 km· h^?1 and 184.8 ± 9.9 ml· kg^?1· km^?1 at 20 km· h^?1, which corresponded to a caloric cost of running of 0.94 ± 0.07 kcal ·kg^?1·km^?1 and 0.93 ± 0.07 kcal· kg^?1· km^?1. We found no significant correlations between oxygen and energy cost of running and biomechanical variables and ground reaction forces at either 12 or 20 km· h^?1. However, ground contact times were ~10.0% shorter (very large effect) than in previously published literature in elite runners at similar speeds, alongside an 8.9% lower oxygen cost (very large effect). These results provide evidence to hypothesise that the short ground contact times may contribute to the exceptional running economy of Kenyan runners.  相似文献   

Relationship between foot strike pattern,running speed,and footwear condition in recreational distance runners     

Roy T. H. Cheung  Rodney Y. L. Wong  Tim K. W. Chung  R. T. Choi  Wendy W. Y. Leung  Diana H. Y. Shek 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(2):238-247

Compared to competitive runners, recreational runners appear to be more prone to injuries, which have been associated with foot strike patterns. Surprisingly, only few studies had examined the foot strike patterns outside laboratories. Therefore, this study compared the foot strike patterns in recreational runners at outdoor tracks with previously reported data. We also investigated the relationship between foot strike pattern, speed, and footwear in this cohort. Among 434 recreational runners analysed, 89.6% of them landed with rearfoot strike (RFS). Only 6.9 and 3.5% landed with midfoot and forefoot, respectively. A significant shift towards non-RFS was observed in our cohort, when compared with previously reported data. When speed increased by 1 m/s, the odds of having forefoot strike and midfoot strike relative to RFS increased by 2.3 times and 2.6 times, respectively. Runners were 9.2 times more likely to run with a forefoot strike in minimalists compared to regular running shoes, although 70% of runners in minimalists continued to use a RFS. These findings suggest that foot strike pattern may differ across running conditions and runners should consider these factors in order to mitigate potential injury.  相似文献   

论“三个代表”与解放思想的统一性     

肖芳 《怀化学院学报》2002,21(4):9-10

论述了“三个代表”与解放思想的辩证关系 ,即坚持“三个代表”是解放思想的政治基础 ,只有坚持“三个代表”才能谈得上思想的真正解放。同时 ,只有在解放思想的前提下 ,才能更好地把“三个代表”的坚持建立在科学的基础上。并且用唯物史观的方法论、认识论来分析认识坚持“三个代表”与解放思想之间的共性与个性 ,在实践中把两者有机地结合起来  相似文献   

Gender differences in the junior secondary (grade 7) mathematics curriculum in Hong Kong     

K. C. Cheung 《Educational Studies in Mathematics》1989,20(1):97-103

This article seeks to examine gender differences across the mathematics curriculum in the various topic areas and mathematical abilities. It is suggested that a profile of these differences, when compared with students at different grade levels or across curricula, would be more fruitful for classroom teachers and curriculum developers. Breakdown and discriminant function statistics reveal that boys performed better than girls in Geometry and excelled in comprehension, and solving routine and non-routine problems. Girls were better at mathematical manipulation problems.  相似文献   

Later life learning experiences: listening to the voices of Chinese elders in Hong Kong     

Maureen Tam 《International Journal of Lifelong Education》2016,35(5):569-585

Abstract

Governments’ anxieties about ageing populations are mostly concerned with the costs of welfare, care and health provision which all have to be paid for by an ever dwindling working population. However, research in later life learning indicates the significant role that lifelong learning can play in promoting mental well-being and resilience, and in assisting with maintaining personal self-confidence and self-coping strategies that prevent cognitive decline in an ageing population. This paper draws on the research with a group of Chinese elders in Hong Kong, who provide information about their experiences and views on learning in later life, including the meaning of learning, barriers to participation, learning interests, needs, motivations, and instructional preferences. Both quantitative and qualitative findings are reported to shed light on later life learning experiences, which contribute to the global understanding of later life learning and serve to inform the development of policy and practice geared to the planning and provision of opportunities to keep learning at the later stages of life.  相似文献   

Nationalistic Education in a Post-colonial Age: the Impact of Study Trips to China and the Development of Hong Kong Students' National Identity     

Sammy King-fai Hui  Frankie Ka-ki Cheung  Yama Yuk-ngo Wong 《Asia Pacific Journal of Education》2004,24(2):205-224

With the return of its sovereignty to the People's Republic of China (PRC) on 1 July 1997, Hong Kong attained a new political status as a Special Administrative Region. Hong Kong students, under British rule, had long been receiving de-politicised education, and a sense of belonging to China was limited to the cognitive domain of Chinese history. The ideal of promoting national identity, underpinned in the current civic education curriculum, is proving to be a difficult task. While much literature has documented how curriculumbased educational practices fail to instil students with such an identity, little study has been undertaken to suggest effective alternatives and to examine how they work. This paper reports a study investigating the impact of study trips on developing students' national identity. Through observation and interviews, it takes an in-depth look into students' experience, into how they identify with a Chinese identity. Results indicate that though the study trips help to nurture the cognitive and affective dimensions of national identity, there are limits and possibilities involved. This paper concludes with reminders which teachers should have taken into account when thinking of using co-curricular activities to address the legitimate need of fostering nationalistic education.  相似文献   

Acute fatigue negatively affects risk factors for injury in trained but not well-trained habitually shod runners when running barefoot     

Nicholas Tam  Devon R. Coetzee  Safwaan Ahmed  Robert P. Lamberts  Yumna Albertus-Kajee  Ross Tucker 《European Journal of Sport Science》2017,17(9):1220-1229

Introduction: Many factors may contribute to running-related injury. These include fatigue and footwear, the combination of which has rarely been studied, in particular with reference to barefoot running, recently advocated as a method to reduce injury risk. Methods: Twenty-two runners (12 well-trained and 10 trained) participated in a 10?km fatiguing trial. Knee and ankle joint kinematics and kinetics and electromyography were assessed during overground running in the barefoot and shod condition. This was performed pre- and post-fatigue using a motion capture system and force platforms. Results: Initial loading rate increased in the trained runners when barefoot but not shod. Shod knee stiffness increased in both groups after fatigue, whereas barefoot knee stiffness decreased only in the trained group. A reduction in barefoot bicep femoris pre-activation was found in both groups. During stance, a reduction in vastus lateralis and biceps femoris and an increase in tibialis anterior activity were found over time in both groups and conditions. Trained runners decreased gluteus medius and increased lateral gastrocnemius median frequency for both conditions after fatigue. Conclusion: When fatigued, gait adjustments in habitually shod runners may increase injury risk when running barefoot. Training status may be a risk factor for injury, as less-trained runners experience muscular fatigue changes that may compromise ground reaction force attenuation. Caution is recommended when transitioning to pure barefoot running.  相似文献   

All Roads Lead to the American City by Peter Swirski,Editor     

Lisa Cheung 《Journal of American culture (Malden, Mass. : 2003)》2008,31(1):104-105

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Core-shell hydrogel beads with extracellular matrix for tumor spheroid formation     

L. Yu  S. M. Grist  S. S. Nasseri  E. Cheng  Y.-C. E. Hwang  C. Ni  K. C. Cheung 《Biomicrofluidics》2015,9(2)

Creating multicellular tumor spheroids is critical for characterizing anticancer treatments since they may provide a better model of the tumor than conventional monolayer culture. Moreover, tumor cell interaction with the extracellular matrix can determine cell organization and behavior. In this work, a microfluidic system was used to form cell-laden core-shell beads which incorporate elements of the extracellular matrix and support the formation of multicellular spheroids. The bead core (comprising a mixture of alginate, collagen, and reconstituted basement membrane, with gelation by temperature control) and shell (comprising alginate hydrogel, with gelation by ionic crosslinking) were simultaneously formed through flow focusing using a cooled flow path into the microfluidic chip. During droplet gelation, the alginate acts as a fast-gelling shell which aids in preventing droplet coalescence and in maintaining spherical droplet geometry during the slower gelation of the collagen and reconstituted basement membrane components as the beads warm up. After droplet gelation, the encapsulated MCF-7 cells proliferated to form uniform spheroids when the beads contained all three components: alginate, collagen, and reconstituted basement membrane. The dose-dependent response of the MCF-7 cell tumor spheroids to two anticancer drugs, docetaxel and tamoxifen, was compared to conventional monolayer culture.  相似文献   

Teachers Curating Virtual Exhibitions for Learning Visual Arts: A Study of Impact and Effectiveness     

Cheung-On Tam  Claire Ka-Yan Hui 《The International Journal of Art & Design Education》2023,42(3):469-485

Although visual arts teachers have free access to high quality online artwork images offering them immense teaching resources, making meaningful use of them remains a pedagogical challenge. During the COVID-19 pandemic, the transition from face-to-face to online teaching caused an immediate need for teachers to enhance their digital competencies and technological capability for planning and delivering a blended art curriculum. Herein, I propose a ‘teacher-curator pedagogy’ via a study in six primary and secondary schools in Hong Kong to assess its effectiveness. The study took place in the academic year of 2021-22 with 331 student participants. The proposed pedagogy puts visual arts teachers in the role of ‘digital curators’ who create virtual exhibitions for teaching art appreciation and artmaking. This paper addresses the theoretical framework, implementation strategies, and the results of the study highlighting its effectiveness, impact and limitations on teaching when using teacher-curated virtual exhibitions in both physical and virtual learning contexts. It was found that the technological capacity and confidence of the teacher participants was enhanced through the use of online resources and virtual exhibition tools. Making use of the 3D presentation of exhibits in themes and context through digital content curation, the teachers engaged students with deep interaction through the blending of online and face-to-face teaching. However, the proposed pedagogy was limited by the high demand of training and preparation work, hardware and software support, and difficulties in assessing and monitoring learning beyond class.  相似文献