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George Dallas 《Sports biomechanics / International Society of Biomechanics in Sports》2020,19(4):467-482
ABSTRACT The aim of this study was to investigate if a visible target for the hurdle take-off would influence the onset of visual regulation and hurdle kinematics during the approach run. Ten elite male gymnasts (age 23.4 ± 4.9 years, height 1.68 ± 0.06 m, mass 63.3 ± 6.2 kg) performed six handspring vaults with a full approach run under two controlled conditions: (a) with a 5-cm white tape on the runway marking the last touchdown of the approach run and the commencement of the hurdle (tape condition—T) and (b) under the standard vaulting regulations (non-tape condition—NT). Spatiotemporal data of the approach run and the hurdle were collected by four stationary and one panning cameras (sampling rate 300 fps). Eight out of 10 gymnasts commenced regulation earlier under T than under NT. Under T condition, horizontal velocity (Vx to = 9.06 ± 0.41 m/s) and vertical velocity (V to = 9.35 ± 0.37 m/s) was significantly faster than under NT condition (Vx to = 8.85 ± 0.49 m/s; V to = 9.11 ± 0.47 m/s). Introducing a target for the hurdle facilitates an early onset of step regulation and significantly improves the kinematics of the hurdle. 相似文献
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Dallas R. Jensen 《Journal of College Counseling》2003,6(1):25-34
College students' sleep habits are changing dramatically, and related sleep problems are increasing. The author reviews the current literature on sleep problems, focusing on the college student population. An explanation of the basics of sleep is provided as a base for understanding sleep disorders. The unique challenges of college settings are discussed as they apply to understanding sleep problems, and suggestions are made for professionals who work with college students. 相似文献
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美国以一个诉讼多的国度而闻名于世。但在美国法院提起确认不侵犯知识产权之诉却决非易事。原告必须满足美国《宪法》"案例和争议"要求才可起诉。美国《确认不侵权法案》的标准并未明确规定处理Medlmmune(医学免疫公司)诉 相似文献
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We understand very little about what is special that leaders do to facilitate improvement that is both transformational and lasting in previously persistently failing schools in the United States. Relatively little is understood about change not just during the initial turnaround stage, but that endures on the larger journey as the school becomes a healthy organisation for adults and students. This lack of understanding is likely due to the lack of data sources because schools struggle to attain turnaround, let alone maintain the improvement and continue to grow. We conducted a literature review of frameworks implicated in leading a sustained school turnaround. This study synthesises existing frameworks relevant to implicated constructs of (1) school turnaround, (2) effective educational leadership, (3) turnaround external to education, and (4) sustained improvement external to education through developing a cohesive set of practices to inform the work of researchers and practitioners. We end by suggesting that this framework be tested and refined through examination of principal data so that it more robustly represents the work that leaders of sustained improvement undertake. 相似文献