起跳过程送髋技术对跳远的影响

研究目的:跳远起跳过程中髋关节技术特征是跳远动作中最为重要的部分,对提高与改进跳远起跳技术有着重要的影响,掌握在跳远的起跳、着板、缓冲、蹬伸阶段"送髋"的角度和方法,为提高我国跳远水平提供具体量化参考指标。研究方法:根据我国运动员调控髋关节运动的状况和国内与国外优秀运动员跳高的差距,通过对比研究起跳过程中髋关节技术特征。研究结果和结论:跳远运动必须合理地完善起跳技术动作,在训练中专门发展髋关节肌肉的力量,以及髋关节灵活性,有意识地运用髋关节动作协调非常重要。     

田径速度性项群“髋动力”研究综述

近年来,在田径速度性项群中尤其是短跑途中跑动力来源论的研究一直成为争论的热点话题,然而研究较为突出的"髋动力"来源论已普遍被大家所接受.通过对"髋动力"学说进行综述研究,对"髋动力"研究的思路作进一步梳理,阐释"髋动力"来源论的科学性、合理性,旨在为今后的教学和训练提供科学的理论依据.     

Differences in hamstring activation characteristics between the acceleration and maximum-speed phases of sprinting

This study aimed to investigate activation characteristics of the biceps femoris long head (BFlh) and semitendinosus (ST) muscles during the acceleration and maximum-speed phases of sprinting. Lower-extremity kinematics and electromyographic (EMG) activities of the BFlh and ST muscles were examined during the acceleration sprint and maximum-speed sprint in 13 male sprinters during an overground sprinting. Differences in hamstring activation during each divided phases and in the hip and knee joint angles and torques at each time point of the sprinting gait cycle were determined between two sprints. During the early stance of the acceleration sprint, the hip extension torque was significantly greater than during the maximum-speed sprint, and the relative EMG activation of the BFlh muscle was significantly higher than that of the ST muscle. During the late stance and terminal mid-swing of maximum-speed sprint, the knee was more extended and a higher knee flexion moment was observed compared to the acceleration sprint, and the ST muscle showed higher activation than that of the BFlh. These results indicate that the functional demands of the medial and lateral hamstring muscles differ between two different sprint performances.     

针对步行平衡稳定性的外骨骼欠驱动髋关节设计

为改善脑卒中患者穿戴下肢外骨骼机器人进行步行康复训练时,步行平衡稳定性不足的问题,提出髋关节内收/外展自由度控制机理和设计方法,通过基于零力矩点理论的步行平衡稳定性分析,研究髋关节内收/外展主动运动对人机系统平衡的作用。通过设定欠驱动髋关节内收/外展运动自由度,改善人机系统步行平衡,并利用单电机驱动单元实现左右两侧髋关节内收/外展运动的协调控制,从而在运动安全的前提下提升步行平衡安全性。通过MATLAB与ADAMS仿真分析,分别验证步行平衡稳定性和欠驱动方案的有效节能性。仿真结果显示,欠驱动方案相比传统每个关节分别安装驱动的方案,扭矩降低了32.52%。该步行平衡解决方案与欠驱动设计方法对促进康复外骨骼机器人应用推广具有重要意义。     

Accuracy and Feasibility of Video Analysis for Assessing Hamstring Flexibility and Validity of the Sit-and-Reach Test

The accuracy of video analysis of the passive straight-leg raise test (PSLR) and the validity of the sit-and-reach test (SR) were tested in 60 men and women. Computer software measured static hip-joint flexion accurately. High within-session reliability of the PSLR was demonstrated (R > .97). Test-retest (separate days) reliability for SR was high in men (R = .97) and women R = .98) moderate for PSLR in men (R = .79) and women (R = .89). SR validity (PSLR as criterion) was higher in women (Day 1, r = .69; Day 2, r = .81) than men (Day 1, r = .64; Day 2, r = .66). In conclusion, video analysis is accurate and feasible for assessing static joint angles, PSLR and SR tests are very reliable methods for assessing flexibility, and the SR validity for hamstring flexibility was found to be moderate in women and low in men.     

Biomechanical loading of the hip during side jumps by soccer goalkeepers

Abstract

There is a risk of hip injury in dives to the side by soccer goalkeepers. In this study, we assessed hip loading in goalkeepers when performing such dives. The experiments were conducted in a laboratory setting using an in-ground force plate as well as on a grass surface when the athletes were equipped with force sensors. The forces acting on the hip were measured and high-speed video analysis was performed, allowing the investigation of the dive characteristics and techniques. The peak force values recorded in the laboratory setting ranged from 3 to 8 kN, which corresponded to 4.2–8.6 times body weight. The vertical impact velocities reached 3.25 m · s^?1. In the field experiments, a hip loading of 87–183 N · cm^?2 was determined. We found that goalkeepers who perform a rolling motion reduce their hip loading. The data provided by this study add to the biomechanics database and contribute to the establishment of injury criteria. Such information is necessary to develop and implement strategies to help prevent hip injuries.     

基于Proteus软件的单片机仿真实例

本文以AT89C51单片机显示汉字点阵系统为例,介绍了仿真软件Proteus的基本功能和特点,研究如何使用仿真软件进行仿真,以及和Keil软件联合仿真的方法,对学生学习Proteus仿真软件具有一定的指导意义,而且提高开发效率,降低开发成本,缩短开发周期。     

全髋关节置换术后脱位原因的分析

引起手术后关节脱位的因素有许多,可以从患者情况、假体设计、手术操作和康复护理这几个方面来考虑。假体置入位置欠佳、两侧软组织不平衡(尤其是外展肌的破坏)是造成THR术后脱位的主要原因;术前全面评价患者局部情况,并注意一些骨性标记的变异,术中注意正确安装假体,仔细清理髋臼周围的骨赘与骨水泥以及注意髋周围软组织的修复,关闭伤口前认真检查手术髋的稳定性,是预防THR术后脱位的有效措施。     

浅析如何提高我国短跑运动员途中跑的能力

途中跑技术在田径短距离跑项目中是最重要的一个技术环节,对短跑成绩起决定作用. 目前,我国短跑运动停滞不前,关键一环是运动员途中跑的能力没有得到有效的提高.通过和世界优秀运动员的比较,从运动技术、运动能力、能量供应等不同角度,分析影响我国短跑运动员途中跑能力的问题所在,提出解决的有效途径,供大家在以后的教学训练中参考.     

对我国优秀女子铁饼运动员肩、髋动作特征的研究

运用爱捷运动录像三维测量分析系统对我国优秀女子铁饼运动员的肩和髋的动作进行了三维运动学分析。结果表明 :左脚离地时的身体姿势对腾空、过渡阶段和最后用力阶段有着重要的影响 ;在最后用力阶段 ,拉引角数值的增量制约着铁饼运行的距离 ;我国运动员与世界优秀运动员的主要差距在过渡阶段。存在的问题 :运动员没能有效地做出右脚的转扣着地及着地后不停顿的旋转动作 ;左髋带动左大腿促使左脚尽快摆压动作过慢。