Effect of gear ratio on peak power and time to peak power in BMX cyclists     

Lee P. Rylands  Simon J. Roberts  Howard T. Hurst 《European Journal of Sport Science》2017,17(2):127-131

The aim of this study was to ascertain if gear ratio selection would have an effect on peak power and time to peak power production in elite Bicycle Motocross (BMX) cyclists. Eight male elite BMX riders volunteered for the study. Each rider performed three, 10-s maximal sprints on an Olympic standard indoor BMX track. The riders’ bicycles were fitted with a portable SRM power meter. Each rider performed the three sprints using gear ratios of 41/16, 43/16 and 45/16 tooth. The results from the 41/16 and 45/16 gear ratios were compared to the current standard 43/16 gear ratio. Statistically, significant differences were found between the gear ratios for peak power (F(2,14)?=?6.448; p?=?.010) and peak torque (F(2,14)?=?4.777; p?=?.026), but no significant difference was found for time to peak power (F(2,14)?=?0.200; p?=?.821). When comparing gear ratios, the results showed a 45/16 gear ratio elicited the highest peak power,1658?±?221?W, compared to 1436?±?129?W and 1380?±?56?W, for the 43/16 and 41/16 ratios, respectively. The time to peak power showed a 41/16 tooth gear ratio attained peak power in ?0.01?s and a 45/16 in 0.22?s compared to the 43/16. The findings of this study suggest that gear ratio choice has a significant effect on peak power production, though time to peak power output is not significantly affected. Therefore, selecting a higher gear ratio results in riders attaining higher power outputs without reducing their start time.  相似文献   

Campus commons: The calculus of grief     

Lee Burdette Williams 《About Campus》2010,15(1):28-31

Lee Burdette Williams shares her firsthand experience of her students' resilience in the face of loss.  相似文献   

What Is Right About Special Education     

Cynthia R. Chambers  Michael L. Wehmeyer  Yumiko Saito  Kerry M. Lida  Youngsun Lee  Vandana Singh 《Exceptionality》2013,21(1):3-15

Abstract

Promoting self-determination has become an important aspect of the educational programs of students with disabilities. There is now a sufficient literature base to support some syntheses that enable researchers to judge their progress in this area to date and to provide direction for future research and practice. For this study, we conducted a literature review of studies that measured or examined global self-determination.  相似文献   

Cultivating a sense of belonging in part-time students     

David Kember  Kenneth Lee  Natalia Li 《International Journal of Lifelong Education》2013,32(4):326-341

This study investigated the sense of belonging of part-time students through interviews with 53 novice or experienced students enrolled in part-time programmes in Hong Kong. It was found that students were more easily able to affiliate with their class groups or teaching staff than with their department or university. Seven methods are suggested for promoting a sense of belonging. Class cohesiveness can be developed through learning activities and maintaining classes as a cohort. Relationships with teaching staff can be developed through encouraging interaction, providing good quality teaching and making a positive initial impression. There was also evidence that a sense of belonging was more likely to develop if enrolment was through departments and part-time students had access to resources and facilities. The data showed that promoting a sense of belonging contributed to better quality learning outcomes and increased the chances of students completing programmes.  相似文献   

Kicking modality during erratic-dynamic and static condition effects the muscular co-activation of attacker     

Tae-Whan Kim  Sang-Cheol Lee  Se-Kee Kil  Sung-Chul Kang  Young-Tae Lim 《Journal of sports sciences》2017,35(9):835-841

The purpose of the study was to investigate the effect of different kicking modality, i.e., erratic-dynamic target (EDT) versus static target (ST) on the performance of the roundhouse kick in two groups of taekwondo athletes of different skill level. Three-dimensional analysis and surface electromyography (SEMG) analysis were performed on 12 (Group A: six sub-elite, Group B: six elite) athletes to investigate muscle co-activation pattern under two conditions, i.e., EDT versus ST. In the results, the muscle recruitment ratio of the agonistic muscles was higher for Group A, whereas Group B had higher recruitment ratio for antagonist muscles. Overall, the co-activation index (CI) of hip joints appeared higher in the extensors for Group A, whereas higher CI was observed in flexor muscles for Group B with comparatively higher CI during EDT condition than ST condition. Higher value of CI was observed in flexor muscles of the knee joints among Group A during EDT conditions, in contrast, higher CI in the extensor muscles was observed among Group B during ST conditions. In conclusion, the study confirmed that erratic-dynamic movements of target could change the movement coordination pattern to maintain the joint stability of participants.  相似文献   

The information gulag: Rethinking openness in times of national danger     

Lee S. Strickland 《Government Information Quarterly》2005,22(4):546-572

The founding fathers of the United States recognized that freely available information and an educated citizenry were essential to the functioning of a representative democracy. But almost as soon as the ink dried on the Constitution, political forces moved, and have continued to move, to restrict the flow of information from the government to the public, as well as among members of the public. This article examines whether information availability has become a victim of the war on terrorism – whether the nation has entered a time in which legal and policy initiatives are creating information gulags – secreting government information and restricting communications among members of the public, including the academic community. This article explores how policy is shaping the information relationship among the government, the public, academia, and the media and whether new models may be appropriate and more beneficial to society. In doing so, we examine in depth not only public access to government information but also the emerging and vital issue of government restrictions on scholarly exchange, as most recently presented by the legal dispute between the Institute of Electrical and Electronic Engineers (IEEE) and the Office of Foreign Asset Control (OFAC), Department of Treasury, and subsequently the litigation brought by the Association of American University Presses (AAUP).  相似文献   

Grounded theory analysis of e-government initiatives: Exploring perceptions of government authorities     

Jungwoo Lee  Jinhwa Kim 《Government Information Quarterly》2007

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反者道之动(2本)——后现代主义思潮与教育     

李永全 《和田师范专科学校学报》2006,26(2):1-3

从后现代主义的起源、流变及其表现形式来看,后现代主义思潮具有反传统、反理性、多元化、自组织等特征.这种思潮已经波及科学及教育领域,正在并将继续对教育科学的理论及实战产生诸多正面、负面的影响.  相似文献   

Libraries,publishers and information provision: Life after FIGIT     

David Lee 《Learned Publishing》1996,9(1):29-31

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reading without words     

Lee Bennett Hopkins 《Early Childhood Education Journal》1973,1(2):31-36

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