大学生步态特点与踝关节等动肌力的相关性研究

运用Cybex-NORM等速肌力测试系统,RSscan足底压力板测试系统对27名在校大学生（男15名,女12名）进行步向角测试,30°/s,120°/s两种角速度踝关节内收、外展的等动肌力测试,旨在探讨大学生步态特点及内、外八字形成的肌力学机制.研究结果：（1）大学生青年步向角的正常范围为1～15°;（2）男性步向角均值约为11.4°,女性步向角均值约为4.7°,男女性别差异具显著性;（3）角速度为30°/s和120°/s的内收、外展峰力矩,内收、外展平均力矩以及外展内收力矩比值均显示男性大于女性,且有显著性差异;（4）踝关节外展、内收肌力并非随着步向角的增大而增大或减小,内、外八字步态踝关节外展、内收肌力均小于正常步态;（5）30°/s和120°/s两种速度下,3种步态的踝关节外展内收肌力比都几近相等,没有显著性差异.结论：（1）23岁左右青年大学生步向角的正常范围为1～15°,小于1°为内八字步态,大于15°为外八字步态;（2）步向角、踝关节外展、内收肌力矩,外展内收肌力比均存在性别差异;（3）内、外八字不良步态形成的肌力学原因是踝关节外展、内收肌力同时薄弱,而不是外展内收肌力发展失衡,深层原因需要进一步深入探讨和研究.     

交变负荷训练法对下肢肌肉力量训练效果的影响

目的:采用自制振动台为干预手段对下肢肌肉进行力量交变负荷力量训练,研究交变负荷力量训练对肌肉力量增长效果的影响.方法:上海体育学院体育教育专业男子跳远运动员10名,随机分为1)"交变负荷训练组"(Ⅰ组,n=5),振动刺激的频率为20～25 Hz,加速度为15～20m/s2;2)"传统力量训练组"(Ⅰ组,n=5),两组共接受8周训练,实验前后一周内利用Biodex对原地纵跳能力和下肢三大关节屈伸肌肌群的一般、快速力量和功率等指标进行测定.结果:振动刺激训练能够有效地提高受试者的原地纵跳能力、肢三大关节屈伸肌肌群的一般和快速力量,组间比较具有显著性差异.结论:交变负荷力量训练法能有效地提高肌肉力量训练的效果.     

船载式AMP电缆卷筒转矩控制方法

为在船舶持续使用岸电的过程中对电缆张力进行有效的监测和控制,研究电缆重力变化和电缆卷筒转矩变化的数学模型。基于中远海运科技股份有限公司研制的船载式AMP电缆卷筒CS-AMPJC-H2,结合通用变频原理,设计一套卷筒转矩控制方案。该方案能实现对电缆张力的有效控制。     

青少年击剑运动员膝关节屈伸肌群等速肌力测试分析

运用文献资料法、实验法、数据统计法,对安徽省击剑队青少年运动员下肢膝关节屈伸肌群等速肌力进行分析研究,客观评价青少年与成年击剑运动员在下肢膝关节屈伸肌群力量特征方面存在的差异,同时为青少年击剑专项力量训练提供理论依据和针对性建议。     

攀岩运动员正反握法下肘关节等速肌力及峰力矩角度研究

采用德国Isomed2000等速肌力测试系统,通过对优秀攀岩运动员左右肘关节正反两握法下的等速向心肌力及峰力矩角度的测试与分析,探讨肘关节屈伸肌群在攀岩竞技能力发展中的作用,为科学安排专项训练及预防运动损伤提供一定的理论依据。其测试结果表明：优秀攀岩运动员肘关节屈伸峰力矩（PT）随测试速度的增大而减小,峰力矩屈伸比值随...     

汽车制动器试验台模拟控制方法分析

本文主要研究制动器试验台上进行汽车制动性能模拟测试问题。通过对试验台上制动过程的等效分析,建立了对电动机进行能量补偿与利用电流来补偿模拟惯量存贮动能的方法,最后根据能量守恒定律建立了驱动电流依赖于可观测量的数学模型。文中对给定的某种试验方法进行了评价,并提出了改进试验精度的方法。     

应用开关磁阻电机激励参数控制转矩脉动仿真

针对开关磁阻电机转矩脉动控制问题,以六相12/10开关磁阻电机为例,根据相电感、相电流、转子位置相互关系,建立非线性简化数学模型。采用关断角模糊补偿控制减小转矩脉动,由关断角滞后带来的输出转矩减小问题,采用开通角自调整控制,设计开通角自调整控制器,优化相电流,提高平均转矩输出。应用MATLAB构建开关磁阻电机控制系统仿真模型,得到开通角自调整与关断角模糊补偿仿真波形,仿真实验表明转矩脉动减小,平均输出转矩增大,采用的控制策略是可行的,为实际开关磁阻电机调速控制系统的设计提供了有效的方法。     

Comparison of methods for determining power generated on a rope-braked cycle ergometer during low-intensity exercise

This study compares the instrumentation and analysis techniques used when determining the power expended pedalling a rope-braked ergometer manufactured by Monark (Sweden) during a low intensity test. Power values were generated by eight subjects. The instrumentation consisted of load cells to measure the rope brake forces, a tachometer to measure the flywheel velocity and instrumented pedal cranks manufactured by Schoberer Rad Messtechnik (SRM). The subjects pedalled a rope-braked ergometer at 60 rev min^-1, against a resistance of 3 kg, for 5 minutes. Three different measurements of the mean power were recorded and these were compared with the value given by Monark. The SRM cranks provided two sets of results using different software packages supplied with the cranks. SRM standard software is used for taking measurements during training and cycle races over long time periods. An additional piece of software is provided by SRM called Ptnew, which gives readings of torque and pedal cadence over periods up to 30 seconds. Using the values supplied by Monark each subject generated 180 W of power. The mean power for the eight subjects, measured using the SRM cranks, was 170.36 W (SD 4.11) using the alternative SRM software (Ptnew) over a 30 second period and 173.68 W (SD 2.21) using the standard SRM software. From the direct measurement of the brake forces and flywheel velocity the mean power across the eight subjects was 148.90 W (SD 5.89). The SRM cranks measure the input power, whereas the direct measurement system measures the power output excluding mechanical losses. These values give a figure for the mechanical efficiency for the roped-braked ergometer of 88%. It was found that Monark overestimates the power generated by the subjects when compared with both the SRM systems and the direct measurement instrumentation.     

广东省优秀短跑、跨栏、三级跳运动员髋关节肌肉力量的等速测试研究

通过Cybex-6000等速测试系统,对广东省优秀短跑、跨栏、三级跳远项目30名(男16人、女14人)一线训练运动员髋关节进行等速向心肌力测试,对髋关节伸屈肌在60°/s、120°/s、180°/s、240°/s四种测试速度下的峰力矩、功及功率的变化进行了研究,为优秀运动员有针对性的力量训练提供科学依据.实验结果表明:随着收缩速度的增加,髋关节伸展肌相对峰力矩有下降的趋势,相对功呈逐渐减小的趋势,相对功率呈明显增大的趋势,髋关节屈伸肌峰力矩比值在0.71～0.79范围内波动,髓关节屈伸肌做功比值呈略有减少的趋势.     

Automatic measurement of key ski jumping phases and temporal events with a wearable system

We propose a new method, based on inertial sensors, to automatically measure at high frequency the durations of the main phases of ski jumping (i.e. take-off release, take-off, and early flight). The kinematics of the ski jumping movement were recorded by four inertial sensors, attached to the thigh and shank of junior athletes, for 40 jumps performed during indoor conditions and 36 jumps in field conditions. An algorithm was designed to detect temporal events from the recorded signals and to estimate the duration of each phase. These durations were evaluated against a reference camera-based motion capture system and by trainers conducting video observations. The precision for the take-off release and take-off durations (indoor < 39 ms, outdoor = 27 ms) can be considered technically valid for performance assessment. The errors for early flight duration (indoor = 22 ms, outdoor = 119 ms) were comparable to the trainers' variability and should be interpreted with caution. No significant changes in the error were noted between indoor and outdoor conditions, and individual jumping technique did not influence the error of take-off release and take-off. Therefore, the proposed system can provide valuable information for performance evaluation of ski jumpers during training sessions.