Kinematics and metabolic cost of running on an irregular treadmill surface

The purpose of this study was to investigate the kinematic and metabolic effects of running on an irregular surface. We also examined how altering the frontal plane foot angle (inversion/eversion) at contact using real-time visual feedback would affect these other variables. Sixteen participants completed three running bouts lasting 5–7 minutes each on an irregular surface (IS) treadmill, a traditional smooth surface (SS) treadmill, and on SS while receiving visual feedback of the frontal plane foot angle at contact (SSF) with a goal of matching IS foot angle on SS. Frontal plane foot angle increased 40% from IS to SS (IS: 8.4 ± 4.09°, SS: 11.8 ± 4.52°, P < 0.0001, ES 1.40). Knee flexion angle at contact decreased 33% from IS to SS (IS: 9.2 ± 4.88°, SS: 6.2 ± 5.03°, P < 0.0001, ES 1.30). Rate of oxygen consumption decreased by 10% from IS to SS (IS: 37.9 ± 5.68 ml·kg^?1·min^?1, SS: 34.1 ± 5.07 ml·kg^?1·min^?1, P < 0.0001, ES 3.05). PSD of leg accelerations decreased by 38% (IS: 0.17 ± 0.07 g²/Hz, SS: 0.106 ± 0.05 g²/Hz, P < 0.000, ES 1.69). Frontal plane foot angle decreased by 14% from SS to SSF (SS: 11.8 ± 4.52°, SSF: 10.1 ± 4.42°, P = 0.027. ES 0.62) but did not result in significant changes in any other variables. There were no significant differences in shock attenuation between any conditions (IS: ?9.8 ± 2.26 dB, SS: ?9.5 ± 3.12 dB, SSF: ?9.9 ± 2.62 dB, P = 0.671). Running with greater eversion on the irregular surface may be an attempt by runners to reduce the perceived potential of an inversion ankle sprain. As a partial compensation for the decreased foot angle, runners increased knee flexion. This maintained shock attenuation but increased the rate of oxygen consumption. Altering the foot angle at contact using feedback on the SS caused the knee angle at contact to increase, but did not change shock attenuation or metabolic cost.     

秧歌舞练习对老年女性BMD与平衡能力的影响

以秧歌舞练习为干预因子，探讨长期秧歌舞练习对老年女性BMD（骨密度）及平衡能力的影响。结果显示：实验组的BMD值和左、右足的闭眼单足站立时间显著高于对照组（P〈0．05，P〈0．01）。说明长期坚持秧歌舞练习能有效地维持较高骨含量。改善机体的平衡能力，对老年女性防治骨质疏松症和防摔倒具有重要意义。     

投掷最后用力的合理顺序研究

对投掷最后用力顺序的分析,得出:最后用力时,推动骨盆作向前上方转动的动力矩来源于右侧腿的踝、膝关节肌肉收缩所形成的转动推力,而髋关节肌肉收缩只是对踝、膝关节肌肉收缩所形成的转动推动力产生协同作用,对骨盆以左侧支撑腿的髋关节为轴的加速转动不产生直接性的效果.投掷最后用力顺序是踝、膝、髋肌肉依次发力.     

练习太极拳对中老年单足站立平衡能力的影响

观察练习太极拳对于中老年单足站立平衡能力的影响。在一年的观察中,经过三次跟踪测试。结果显示：练习组在六个月后和一年后的测试中,睁眼平衡时间比练习前分别增加了5.13S和17.73S,闭眼平衡时间比锻炼前时间分别增加了5.12S和12.91S,均有显著性差异,而对照组略有下降,但无显著性差异。这表明练习太极拳有助于改善中老年机体的平衡能力。     

对短跑途中跑支撑脚后蹬扒地技术的初步探讨

通过对短跑运动员支撑脚后蹬扒地技术进行理论分析,认为运动员在途中跑过程中,支撑脚后蹬扒地是推动人体快速前移和提高大腿前摆效果的主要因素,从而提出了一些有关加强支撑脚后蹬扒地能力训练的方法,以达到提高运动成绩的目的。     

束缚与解放——《湘报》对女性缠足问题的讨论

戊戌变法时期,维新志士在城乡发起了轰轰烈烈的不缠足运动。《湘报》作为湖南维新派的喉舌,对倡导女性放足更是不遗余力,刊载了大量的关于推动女性放足的论说、文告、章程和启事等。这些文章探讨了缠足之源、缠足之害、禁缠之难和禁缠之益。     

奥运会运动员三级跳远技术与运动成绩关系

采用文献资料法、综合分析法等 ,将 (美国 )詹姆斯·海博士实验小组利用SVHS摄像机与PEAK扫描技术采集到的数据 ,对奥运会运动员所采用的技术与运动成绩的关系作全方位的研究。结论 :采用较小的单足跳百分比和较大的跳跃百分比 ,三级跳远成绩越好 ,跳跃式技术是 2 1世纪三级跳远技术的发展方向。     

浅析铅球、铁饼、标枪最后用力的转换衔接阶段常见错误

本文主要通过对学生平时训练的观察,结合各方文献资料,进行研究与分析在投掷项目训练时,铅球、铁饼、标枪运动最后用力的转换衔接阶段的时机与正确方法,陈述正确转换阶段对稳定和提高成绩的重要性,怎样才能更有效地正确地完成转换阶段,避免在技术中出现空中换步和左脚着地或快或慢的现象,根据各方文献资料、逻辑分析法、观察法和实习实践后自我认识理解对此阶段进行分析研究,总结问题出现的原因及提出纠正的方法。     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.     

双侧性迁移理论在高校女生毽球选项课教学中的实验研究

通过对高校女生毽球选项课教学的分组实验研究,探讨双侧性迁移理论在毽球基本技术教学中的应用效果.研究发现在毽球基本技术的学习过程中弱势脚向强势脚迁移的效果要好于强势脚向弱势脚迁移的效果,同时弱势脚掌握技术的好坏取决于弱势脚是否参与学习和练习,弱势脚参与练习的时间也影响着弱势脚掌握技术和技能迁移效果.