String vibration dampers do not reduce racket frame vibration transfer to the forearm

In this study, we examined the effect of string vibration damping devices on reducing racket frame vibration transfer to the forearm. Twenty participants volunteered to hold a tennis racket stationary in a forehand and backhand stroking position while tennis balls were fired at 20 m x s(-1) towards two impact locations, the node of vibration and the dead spot. A three-way analysis of variance with repeated measures on damping condition, impact location and stroke condition was performed on the data. The resonant frequency of the hand-held racket was found to be approximately 120 Hz. No significant differences in amplitude of vibration at the resonant frequency were found for the wrist or the elbow when damped and non-damped impacts were compared. Impacts at the dead spot produced greater amplitudes of vibration (P < 0.01) but no interaction between impact location and string dampers was evident. The string dampers had no effect on the grip force used or the muscle electrical activity in the forearm after impact. In conclusion, we found that string dampers do not reduce the amount of racket frame vibration received at the forearm. We suggest that string dampers remain a popular accessory among tennis players because of their acoustic effects and psychological support rather than any mechanical advantage.     

从手球比赛中运动员受罚情况分析防守上存在的问题

通过对国内外一些重大手球比赛的情况分析，阐述在日常训练中，各级教练员要正确处理好防与攻的关系，加强提高一防一的对抗能力，从而使手球运动的技、战术更向前推进一步。     

名家信箱

中学生阿志宏通过E-mail问: 《中华武术》杂志编辑部的叔叔阿姨,你们好!我想通过“名家信箱”栏目向崔仲三老师询问一个问题,恳请指点。我是一个太极拳爱好者,同时也喜欢散打,请问外家拳能否跟内家拳同时习练?如果能同时练习,应先练哪一个?应注意些什么问题?望老师能给予详细     

The effect of two different 18-week walking programmes on aerobic fitness, selected blood lipids and factor XIIa

Forty-nine previously sedentary or low active individuals aged 40-71 years were allocated to three groups. The long walking group participated in an 18-week walking programme which consisted of walks lasting 20-40 min; the repetitive short walking group completed walks of between 10 and 15 min, up to three times a day, with no less than 120 min between each walk; and the control group maintained their low level of activity. Both walking programmes began at a prescribed 60 min x week(-1), which increased steadily up to 200 min x week(-1) by week 12. During the study, the long walking group walked for an estimated 2514 min (139 min x week(-1)), expending an estimated 67.5 MJ (3.72 MJ x week(-1)) at an estimated 73% of their age-predicted maximum heart rate and 68% of their estimated VO2max. The repetitive short walking group walked for an estimated 2476 min (135 min x week(-1)), expending an estimated 58.5 MJ (3.17 MJ x week(-1)) at an estimated 71% of their age-predicted maximum heart rate and 65% of their estimated VO2max. The results showed a statistically significant reduction in heart rate during a standardized step test (pre- vs post-intervention) in both walking groups, indicating an improvement in aerobic fitness, although the control group showed a higher average heart rate during the post-intervention test, indicating reduced fitness. When compared with the male subjects pre-intervention, the females possessed more favourable levels of high-density lipoprotein (HDL) cholesterol (P< 0.001), apolipoprotein (apo) AI (P < 0.001) and ratios of total cholesterol:HDL cholesterol (P< 0.02) and low-density lipoprotein (LDL) cholesterol: HDL cholesterol (P< 0.02). Compared with the controls post-intervention, the walking groups showed no statistically significant changes in total cholesterol, LDL cholesterol, HDL cholesterol, apo AI, apo AII, apo B, or the ratios of total cholesterol: HDL cholesterol, LDL cholesterol: HDL cholesterol, apo AI: apo B or apo AI: apo AII (P > 0.05). Relative to the walking groups, factor XIIa increased in the control group (P < 0.05). We conclude that, although both walking programmes appeared to improve aerobic fitness, there was no evidence of improvements in the blood lipids or associated apolipoproteins of the walking groups. Further analysis indicated that this apparent lack of change may have been related to the subjects' relatively good pre-intervention blood lipid profiles, which restricted the potential for change. The implications of the observed changes in the coagulation/fibrinolytic factors remain unclear.     

弈在淮海

新沂古称钟吾,位于苏鲁两省交界处,是江苏的北大门。新沂历史悠久灿烂,文化底蕴深厚,孔子、文天祥、徐霞客等都曾在此驻足流连,留下传世名篇。作为中国优秀传统文化的瑰宝,围棋在新沂呈现出蓬勃发展的良好态势,在新沂市围棋协会的大力推动下,成人和少儿围棋活动方兴未艾。     

多源流理论视域下我国体育财政政策的变迁动力研究

体育财政是体育产业发展的基石,也是提高体育治理能力的重要保障。本文基于多源流理论分析框架,运用文献资料法和历史分析法,回顾我国体育财政政策的变迁历程,探寻政策变迁的动力,深入剖析推动政策变迁的3种源流,从历史发展的各个阶段中对体育财政政策样态进行变迁动力描述,并结合我国“体育财政”政策议程的变迁动力进行整合和讨论,发现经济市场的催化以及关注市场失灵等焦点事件在推动“体育财政”政策议程建立的过程中具有积极影响,为我国体育产业的发展和体育财政的优化提供理论参考。     

自己的家园 2013女子围甲第一阶段赛事撷英

2013年6月23日,中国女棋手们盼望已久的女子围棋甲级联赛诞生了。作为一名职业棋手,我感到无比激动和高兴!中国女子棋手终于真正拥有了属于自己的沙场,自己的家园。     

诘棋新作

本人在“诘棋新作”28中的“盘石诘”写过“‘诘研’的‘保留劫”’一文,未曾想得到三村智保九段的回应。他在博客上贴出此文,说“诘棋新作”是他个人的最爱,其作品拿到“诘研”是再合适不过的。多谢三村九段的抬举,虽未曾谋面,想到本人的雕虫小技在“诘研”上现眼,实在汗颜。     

济南体育服装品牌营销的现状及竞争策略分析

随着我国体育产业快速发展,体育服装业正面临着前所未有的机遇和挑战。济南作为山东省的省会城市,其体育事业和经济的发展在全国具有一定的代表性。本文通过文献资料法等研究方法对济南体育服装品牌店的发展现状、影响发展的因素及竞争策略等诸多因素的分析,希望对济南体育品牌店的进一步发展有所帮助并启示我国体育服装业的发展。