Musculoskeletal loading during the round-off in female gymnastics: the effect of hand position

Chronic elbow injuries from tumbling in female gymnastics present a serious problem for performers. This research examined how the biomechanical characteristics of impact loading and elbow kinematics and kinetics change as a function of technique selection. Seven international-level female gymnasts performed 10 trials of the round-off from a hurdle step to flic-flac with ‘parallel’ and ‘T-shape’ hand positions. Synchronized kinematic (3D-automated motion analysis system; 247 Hz) and kinetic (two force plates; 1,235 Hz) data were collected for each trial. Wilcoxon non-parametric test and effect-size statistics determined differences between the hand positions examined in this study. Significant differences (p < 0.05) and large effect sizes (ES>0.8) were observed for peak vertical ground reaction force (GRF), anterior–posterior GRF, resultant GRF, loading rates of these forces and elbow joint angles, and internal moments of force in sagittal, transverse, and frontal planes. In conclusion, the T-shape hand position reduces vertical, anterior–posterior, and resultant contact forces and has a decreased loading rate indicating a safer technique for the round-off. Significant differences observed in joint elbow moments highlighted that the T-shape position may prevent overloading of the joint complex and consequently reduce the potential for elbow injury.     

我国优秀摔跤运动员运动损伤调查分析

研究目的:探讨我国优秀摔跤运动员运动损伤特征、损伤易患部位、导致损伤发生的原因,以期为第28届奥运会的备战提供有效的预防和治疗措施。研究对象:我国备战2004年奥运会的国家摔跤集训队三跤(男子古典跤、男子自由跤、女子自由跤)的44名重点运动员(包括奥运会的8名参赛运动员)。研究结果:从运动损伤性质和种类来看,三跤没有明显区别,都以关节挫伤、韧带损伤和肌肉拉伤最为常见,其次为耳廓损伤和劳损;从运动损伤的部位看,女子自由跤与男子自由跤没有明显区别,损伤部位多发生于膝关节、肘关节、指关节、耳部、肩关节和腰背;但男子古典跤腰背部损伤占第一位,其次为膝关节、肘关节;在三跤中,专项训练中发生的损伤最多;发生损伤的原因主要是准备活动不充分、动作不正确、慢性劳损和场地监督不够等;针灸、推拿是首选的治疗手段,其次为理疗、外敷药物、内服药物等。     

射箭运动员开弓直线力的分析

射箭运动是一项借助弓的弹力,在规定范围内,准确瞄准目标发射的一项体育锻炼项目,对射击运动员开弓直线力的要求较高。文章主要通过查阅大量有关韩国高水平射手的开弓动作技术特征,从理论上进行分析,以揭示开弓动作及具相关技术的潜在规律,旨在有效提高设计运动员的开弓质量和实际比赛水平。     

对我国优秀女子标枪运动员投掷步阶段的重心及角度参数研究

通过查阅大量文献资料获得当前世界优秀女子标枪运动员投掷步阶段的重心及角度参数,以此为基础,采用三维摄像解析法对2012年全国长投公开赛暨奥运会选拔赛女子标枪前3名运动员投掷步阶段的身体特征进行运动学分析,并将中国运动员与世界优秀运动员的相关运动学参数进行比较研究,从中找出中国优秀运动员投掷步技术所存在的不足,为促进女子标枪运动水平的提高提供理论参考。     

Cricket

The laws of bowling in cricket state ‘a ball is fairly delivered in respect of the arm if, once the bowler's arm has reached the level of the shoulder in the delivery swing, the elbow joint is not straightened partially or completely from that point until the ball has left the hand’. Recently two prominent bowlers, under suspicion for transgressing this law, suggested that they are not ‘throwing’ but due to an elbow deformity are forced to bowl with a bent bowling arm. This study examined whether such bowlers can produce an additional contribution to wrist/ball release speed by internal rotation of the upper arm. The kinematics of a bowling arm were calculated using a simple two‐link model (upper arm and forearm). Using reported internal rotation speeds of the upper arm from baseball and waterpolo, and bowling arm kinematics from cricket, the change in wrist speed was calculated as a function of effective arm length, and wrist distance from the internal rotation axis. A significant increase in wrist speed was noted. This suggests that bowlers who can maintain a fixed elbow flexion during delivery can produce distinctly greater wrist/ball speeds by using upper arm internal rotation.     

标枪肘与技术训练关系的探讨

本文采用调查研究方法,明确了标枪运动员肘部损伤发生的基本状况和致伤的主要原因,提出了标枪技术训练中纠正错误动作、避免和减少“标枪肘”损伤发生的基本方法。     

“标枪肘”损伤理论研究

为避免和减少标枪运动员的肘部损伤，本文通过调查．从理论角度分析探讨标枪运动员“标枪肘”发生的一般规律、原因，明确提出预防和训练的关系和重点。     

石油化工管道弯头冲蚀磨损数值模拟

针对油气管道运输系统存在的固液两相流对管道弯头的冲蚀破坏问题,采用CFD软件Fluent中的DPM和k-ε模型模拟多相流冲蚀现象.分析弯头内流场压力流速分布和颗粒运动轨迹,找出弯头最大冲蚀率与冲蚀位置分布规律.研究表明:在弯头内45°外侧壁面区域流场压强最大;弯头内流体流速在弯头内侧45°近壁区域达到最大值,其附近有二...     

等级运动员左右臂力-电特征的比较观察

采用实验法,通过美国产Humac Norm等速测力系统与PM150 Biopac16导生物电记录仪记录肌力和肌电变化,观察比较了福建师大体育科学学院三级以上（或成绩相当三级以上）等级运动员（都为右利者）左右上臂等速肌力与积分肌电特征。结果表明无论三级还是二级以上运动员均存在左右肌肉活动不平衡的状况,左臂肌在许多特性稍弱于右臂,提示应加强左上臂肌群的力量训练,达到均衡发展的效果。此外二、三级运动员之间亦存在一定的差异。