不同项目女运动员膝关节屈伸肌群肌力特征的比较

利用等速测力技术探讨优秀女子手球、足球和自行车运动员膝关节屈伸肌群肌力特征。结果发现:不同类型的运动项目的运动员膝关节在运动中的作用明显不同,导致膝关节屈伸肌群的力量成分要求也有所不同。因此结合专项特点,合理发展专一性力量素质,才是提高专项力量素质和预防运动性伤病的关键。     

等速测试在评价运动员肌力中的应用

运用文献资料法和专家访谈法对等速测试评价运动员肌力测试方法、指标分析、具体应用和测试中存在的问题几方面进行综述。等速测试作为运动员肌力评价的手段有着较高的使用价值,是一种较先进的一般力量测评手段。但等速测试技术自身存在一些技术瓶颈,而且在测试方法选择上有待统一和完善。     

等速力量测试在监控我国优秀女足运动员力量训练中的应用

利用CYBEX-NormT等速测试系统对我国46名优秀女子足球运动员膝关节屈伸肌群进行等速向心收缩测试与分析,结果提示:(1)提高我国女子足球运动员伸肌的最大力量和快速力量是提高运动能力的关键;(2)为防止腘绳肌的拉伤,应适当提高女足队员的膝关节屈肌的力量;(3)我国女子足球运动员膝关节屈伸肌比率不均衡是导致膝关节损伤的主要原因,力量训练中应加强屈、伸肌力量,尤其是伸肌的力量,以改善屈伸比率的不平衡,防止损伤的发生;(4)我国女子足球运动员存在两腿屈、伸肌力量不平衡现象,在力量训练中,应加强对弱势腿的力量训练,以保证两腿的肌力平衡,防止损伤的发生。     

掷标枪运动员主要关节屈伸肌峰力矩初探

采用澳大利亚KEYLINK公司生产的等速肌力测试系统,对男子标枪运动员肩、肘、髋关节肌肉力量进行等速向心测试,测试速度分别设定为60o/s,180o/s(肩120o/s)。测试的结果表明:屈伸肌由60o/s到120o/s或180o/s时,肩、肘屈伸肌和髋伸肌峰力矩、相对峰力矩减小,髋屈肌峰力矩、屈伸肌相对峰力矩增大;肩、髋屈伸比增大,肘屈伸比减小;屈肌快速力/绝对力比值大于伸肌。     

Mechanical energy generation and transfer in the racket arm during table tennis topspin backhands

The ability to generate a high racket speed and a large amount of racket kinetic energy on impact is important for table tennis players. The purpose of this study was to understand how mechanical energy is generated and transferred in the racket arm during table tennis backhands. Ten male advanced right-handed table tennis players hit topspin backhands against pre-impact topspin and backspin balls. The joint kinetics at the shoulder, elbow and wrist of the racket arm was determined using inverse dynamics. A majority of the mechanical energy of the racket arm acquired during forward swing (65 and 77% against topspin and backspin, respectively) was due to energy transfer from the trunk. Energy transfer by the shoulder joint force in the vertical direction was the largest contributor to the mechanical energy of the racket arm against both spins and was greater against backspin than against topspin (34 and 28%, respectively). The shoulder joint force directed to the right, which peaked just before impact, transferred additional energy to the racket. Our results suggest that the upward thrust of the shoulder and the late timing of the axial rotation of the upper trunk are important for an effective topspin backhand.     

智能化电机测功机实验装置的研制

对他励式电机测功机进行研究，研制出电机测功机实验装置，并设计出单片机数据采集系统对电机转矩进行智能化测量，为学生电机实验提供了良好的条件。     

车用涡轮增压柴油机低速和加速性能研究分析

随着涡轮增压柴油发动机转速下降,其外特性降低,转矩减小,与车用柴油机需扭矩增大不符.为了使其性能与柴油机在负荷和转速变化频繁的整个工作范围内有一良好匹配,需选用合适的增压器和排气系统等来提高其低速和加速性能.     

液力变矩器液黏零速加载试验系统的研制

介绍一种可以实现液力变矩器零速加载的试验系统。为完成液力变矩器的性能试验,特别是液力变矩器零速工况试验,应用液体黏性传动技术设计了液黏零速加载试验系统。试验系统由动力及其控制系统、液黏测功加载及其辅助系统和测控系统组成。试验系统利用电液比例控制技术实现液黏测功机加载转矩控制,应用虚拟仪器思想实现试验数据采集与处理。液黏零速加载试验系统具有广阔的应用前景。     

鼠笼式多相异步电动机转矩的讨论

从对鼠笼式三相异步电动机转子电流相数的分析,对其转矩的表示式进行了详细的讨论。     

Interferential therapy effect on mechanical pain threshold and isometric torque after delayed onset muscle soreness induction in human hamstrings

Abstract

This study was undertaken to examine the acute effect of interferential current on mechanical pain threshold and isometric peak torque after delayed onset muscle soreness induction in human hamstrings. Forty-one physically active healthy male volunteers aged 18?33 years were randomly assigned to one of two experimental groups: interferential current group (n = 21) or placebo group (n = 20). Both groups performed a bout of 100 isokinetic eccentric maximal voluntary contractions (10 sets of 10 repetitions) at an angular velocity of 1.05 rad · s^?1 (60° · s^?1) to induce muscle soreness. On the next day, volunteers received either an interferential current or a placebo application. Treatment was applied for 30 minutes (4 kHz frequency; 125 μs pulse duration; 80?150 Hz bursts). Mechanical pain threshold and isometric peak torque were measured at four different time intervals: prior to induction of muscle soreness, immediately following muscle soreness induction, on the next day after muscle soreness induction, and immediately after the interferential current and placebo application. Both groups showed a reduction in isometric torque (P < 0.001) and pain threshold (P < 0.001) after the eccentric exercise. After treatment, only the interferential current group showed a significant increase in pain threshold (P = 0.002) with no changes in isometric torque. The results indicate that interferential current was effective in increasing hamstrings mechanical pain threshold after eccentric exercise, with no effect on isometric peak torque after treatment.