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1.
神经网络模型预测纵跳时下肢关节内力矩   总被引：3，自引：2，他引：1  
关节肌肉力矩在生物力学研究中是一个非常有价值且应用性颇广的参数.要获得关节力矩数值,需同步测量运动学和地面反作用力参数,并通过逆向动力学(Inversce Dynamic)过程方能求得.目的在于建立推估两种纵跳:直立(Counter-Movement Jump,CMJ)和蹲位(Squat Jump,SJ)时下肢各关节力矩的人工神经网络(artificial ncural network,ANN),通过输入相对较容易测得的地面反作用力参数,推估下肢关节力矩(踝、膝、髋).以10位男性运动员为受试者,在测力台上完成两种纵跳,其所测得的地面反作用力参数作为神经网络模型的输入数据,以下肢各关节力矩为输出数据.经过网络优化后,所求得的最佳神经网络模型为"5-10-3模型"(即输入层有5个神经元;隐藏层为1层,有10个神经元;输出层有3个神经元).该模型所推估出的下肢各关节力矩极值相对误差均小于6%,与实测值的相关系数高达0.95以上,且在推估关节力矩曲线形态与角冲量方面的表现也十分良好,显示通过神经网络以地面反作用力来推估下肢各关节力矩的方法是准确和可行的.  相似文献   

2.
G804.63 20034496从不同高度下落到不同硬度的地面上下肢关节的力学响应=The biomechanical contributions of thelower extremity joints from different height tothe different landing[刊,中,A]/侯曼(北京师范大学体育与运动学院),侯佳(河北师范大学体育学院),王汉玉(北京联合大学应用文理学院生物化学系)//广州体育学院学报.-2003.23(4).-48-50图3 表1 参4(SJ)臂部//腿部//动作//髋关节//力矩//肌肉//力学分折本文研究了人从30cm 和60cm 高度下落到两种不同硬度的地面,即木板地面和海绵垫上下肢关节的力学响应。结果表明从两种高度下落到海绵垫上比落到木板地面时下肢关节的受力、力矩显著减小,关节的角度变化显著增加,从着地到落地停稳所用的时间显著增加。各关节力矩是外力矩与肌肉力矩共同作用的结果,正确的落地技术应该是三个关节的力矩同时减小,掌握正确的落地技术的实质是掌握正确的肌肉被拉伸与收缩的顺序和大小。从30cm和60cm 下落着地后,不论是何种地面条件,三个关节的力矩以髋关节力矩为最大,膝和踝关节肌肉是在髋关节控制下起互相协调作用。  相似文献   

3.
通过ISOMED 2000肌力测试系统对国家古典跤队优秀运动员的膝关节屈伸肌群、肘关节屈伸肌群、躯干屈伸肌群和肩关节外旋、内旋肌群进行了等长肌力测试,获得了优秀古典跤运动员所测关节肌群的力量数据。通过研究所测肌群的相对峰值力矩屈伸比,左右侧肌群相对峰值力矩差异和各关节力矩占躯干力矩百分比,初步揭示了古典跤运动员所测肌群的力量特征。  相似文献   

4.
通过 "逆向动力学计算"的方法,系统揭示了不同水平短跑运动员支撑过程中支撑腿下肢各关节净肌力矩与关节功率特点以及不同水平运动员之间的差异,更为深入地探讨了短跑途中跑技术以及专项力量特点.  相似文献   

5.
目的:对辽宁省排球队女运动员下肢急停纵跳落地时的力矩和最大关节角度进行研究,以期对有膝关节损伤的排球运动员进行科学训练提供参考。方法:以14名辽宁省排球队女运动员为研究对象,将运动员分为两组,其中无伤组8人,损伤组6人,采用三维测力平台和红外光电运动捕捉系统,记录受试者在完成急停纵跳动作落地时的髋关节、膝关节、踝关节的力矩以及最大关节角度数据。结果:在急停纵跳落地时,损伤膝关节的旋转、收展力矩大于无伤组,屈伸力矩小于无伤组,损伤组的髋关节的屈伸、收展、旋转力矩均大于无伤组;损伤组的踝关节旋转力矩小于无伤组,收展力矩和屈伸力矩大于无伤组。损伤组的踝关节在屈伸、收展和旋转时的最大关节角度大于无伤组;损伤组的膝关节在屈伸和收展时的最大关节角度大于无伤组,旋转时小于无伤组;损伤的髋关节屈伸和收展时的最大关节角度大于无伤组,髋关节旋转时的最大关节角度左侧小于无伤组,右侧大于无伤组。结论:膝关节损伤的运动员完成急停纵跳动作落地时,通过代偿性改变增大髋关节力矩、增加膝关节旋转和收展力矩,增大踝关节收展和屈伸力矩,增加膝关节和髋关节在屈伸和收展时活动角度,增加膝关节屈伸和收展时活动角度来完成动作。  相似文献   

6.
目的:研究我国男子自由式摔跤运动员主要关节的肌力表现,找出肌力规律和特征;方法:通过等动测试仪(ISOMED-2000)对我国优秀男子自由式摔跤运动员(共53名)进行主要关节的肌力测试与分析,测试角速度分别为0°/s和180°/s;结果:1)相对最大力矩、相对平均峰力矩及相对平均功率普遍表现出伸肌大于屈肌的特征;2)各关节在两种角速度下,存在同侧屈伸比和异侧同名肌群比较上的显著性差异(P＜0.05),即各关节存在不同程度的失衡性;3)随着角速度的增加,各主要关节的相对最大力矩基本呈现递减特征,但腰背部肌群呈现递增的特征,并且存在不同角速度上的显著性差异(P＜0.05),其屈/伸比值在180°/s时仍然小于1.结论:我国优秀男子自由式摔跤运动员在不同关节上存在肌力的双侧不对称性,并且腰背部表现出对伸肌的高度要求.  相似文献   

7.
对个体膝关节伸屈肌群力学性质的初步研究   总被引：12，自引：2，他引：10  
本文实验对象为10名体院本科男生（20岁），用CYBEX6000测膝屈伸肌群的力矩。一套实验由6个角速度实验组成，分别是60°/s，90°/s，120°/s，150°/s，180°/s，210°/s。实验时，角速度间休息20秒，套间休息半小时。先每个人做3套实验。一天后，每人再做3套实验（实验为等动实验）。各人实验数据按关节角（间隔5度）、角速度组成样本后，求样本平均值和样本标准差。以样本平均值做各关节角的不同速度的伸膝肌群和屈膝肌群的参数曲线族。实验发现，膝伸屈肌群的肌肉力矩，在动作开始和结束的膝角附近，膝伸屈肌群的肌肉力矩离散度大，表现为样本标准差大。其他膝角膝屈伸肌群的肌肉力矩离散度较小。各膝角的肌群力矩参数曲线并不全是随速度的增加而肌群的力矩减小。膝屈伸肌群的肌肉力矩参数曲线族呈现反S形趋势。在高速度时伸肌群表现弱趋势而屈肌群表现强趋势。分析认为是小腿的重力效应。运动员个人膝关节屈伸肌群力量的参数曲线族，可与其高速摄影解析运动学结果对照。对其做膝关节测试范围内任意膝角任意速度的动力进行估计。最大肌群力矩参数曲线可提供各速度下屈伸峰值力矩比，为医疗保健提供依据。  相似文献   

8.
目的考察不同拖拉阻力负荷下,短跑途中跑下肢髋膝踝三关节的动力学变化,探讨拖拉阻力训练对发展关节肌群力量的生物力学机制,从而为运动训练实践提供理论指导。方法采用高速摄像与测力台同步的方法,记录8名短跑运动员在0 N、50 N、80 N和110 N4种阻力条件下途中跑阶段的运动学与动力学数据。结果施加拖拉阻力与不施加拖拉阻力相比,支撑阶段人体重心最大水平速度、步长、着地躯干角、髋角与膝角均呈显著性下降,步频与着地踝角则不存在显著性差异;施加拖拉阻力后,下肢各关节力矩与功率指标峰值均表现为不同程度的下降趋势。结论拖拉阻力跑时,运动员途中跑阶段下肢各关节的力矩及功率输出明显降低,这与阻力条件下重心水平速度的下降有直接关系。  相似文献   

9.
体操运动员跳马落地时下肢受到较大的冲击负荷,通常会导致关节损伤,探寻运动员落地垫力学特性的改变对下肢关节负荷的影响,旨在为下肢关节损伤的预防提供科学依据.首先,通过人体运动仿真软件LifeMod/ADAMS构建19个环节的个性化人体模型,之后,通过受试者落地过程的动作捕捉、高速摄像和测力台实验对模型加以验证,证明所建立模型的有效性.利用所建的模型,对高水平运动员在实际比赛中完成跳马技术动作进行捕捉,随后改变跳马落地垫的力学参数进行仿真研究.结果发现,人体落地冲击分为冲击和平衡两个阶段,人体肌肉骨骼系统具有缓冲减震的功能,踝、膝和髋关节分别延迟15 ms、17ms和19ms达到关节反作用力峰值.另外,落地过程中膝关节的伸肌力矩和髋关节的外展力矩分别在矢状面、额状面内起主导作用.当增加落地垫的阻尼导致踝关节在矢状面内受到的负荷明显增大,但增加刚度对体操运动员负荷的影响相对较小.而在额状面内,增加落地垫的刚度和阻尼导致下肢各关节的力矩明显增大,将增加下肢损伤的风险.  相似文献   

10.
不同负重超等长练习下肢各关节作用分析   总被引：2，自引：0，他引：2  
目的:研究不同负重超等长练习髋、膝、踝关节平均净关节力矩,比较下肢各关节的贡献度,探讨不同负重超等长练习对下肢各关节肌肉力量和爆发力的影响;方法:对16名篮球运动员进行不同负重的下肢超等长练习,采用VICON和三维测力台采集不同负重超等长练习动作的运动学和动力学数据,并经标准逆向动力学计算下肢净关节力矩;结果:无负重超等长练习膝关节贡献度最大,加裁不同负重后的超等长练习髋关节贡献度明显增加.关节贡献度的升高与负重的增加并无线性关系;结论:无负重超等长练习优先发展膝关节肌快速力量;低负重超等长练习主要发展髋关节肌肉绝对力量和爆发力;较大负重超等长练习主要发展髋关节肌肉绝对力量.  相似文献   

11.
Abstract

We aimed to illustrate support leg dynamics during instep kicking to evaluate the role of the support leg action in performance. Twelve male soccer players performed maximal instep kicks. Their motions and ground reaction forces were recorded by a motion capture system and a force platform. Moments and angular velocities of the support leg and pelvis were computed using inverse dynamics. In most joints of the support leg, the moments were not associated with or counteracting the joint motions except for the knee joint. It can be interpreted that the initial knee flexion motion counteracting the extension joint moment has a role to attenuate the shock of landing and the following knee extension motion associated with the extension joint moment indirectly contributes to accelerate the swing of kicking leg. Also, appreciable horizontal rotation of the pelvis coincided with increase of the interaction moment due to the hip joint reaction force on the support leg side. It can be assumed that the interaction moment was the main factor causing the pelvis counter-clockwise rotation within the horizontal plane from the overhead view that precedes a proximal-to-distal sequence of segmental action of the swing leg.  相似文献   

12.
The purpose of this study was to investigate effects of the ground reaction forces on the rotation of the body as a whole and on the joint torques of the lower limbs associated with trunk and pelvic rotation in baseball tee batting. A total of 22 male collegiate baseball players participated in this study. Three-dimensional coordinate data were acquired by a motion capture system (250 Hz), and ground reaction forces of both legs were measured with three force platforms (1,000 Hz). Kinetic data were used to calculate the moment about the vertical axis through the body’s centre of mass resulting from ground reaction forces, as well as to calculate the torque and mechanical work in the lower limb joints. The lateral/medial ground reaction force generated by both legs resulted in the large whole body moment about its vertical axis. The joint torques of flexion/extension of both hips, adduction of the stride hip and extension of the stride knee produced significantly larger mechanical work than did the other joint torques. To obtain high bat-head speed, the batter should push both legs in the lateral/medial direction by utilising both hips and stride knee torques so as to increase the whole body rotation.  相似文献   

13.
The purpose of the investigation was to study the relationship between thrust phase duration, ground reaction force, velocity increase after pole thrust and pole angles versus pole length during double poling in roller skiing. Seven male regional elite cross-country skiers volunteered as subjects for the study. The subjects performed a maximal double pole thrust on roller skis with each of the three different pole lengths: 'short', self-selected (normal) and 'long'. The short and long poles were 7.5 cm shorter and 7.5 cm longer than the self-selected pole length. The subjects made seven maximal pole thrusts with each pole length, which were randomly selected during 21 trials. For each trial the subjects accelerated from a 1.2 m high downhill slope attaining a speed of 3.92 m.s-1 before making a maximal double pole thrust on a force plate placed at the bottom of the slope. The vertical (F2), anterior-posterior (Fy) and mediolateral (Fx) reaction forces of the left pole were measured by the force plate. The positions of the pole were recorded in 3-D by an opto-electronic system. Thrust phase duration, impulse, mean force, velocity increase after pole thrust and pole angles were calculated from the recorded data. Double poling with long poles produced a significantly larger propulsive anterior-posterior reaction force impulse and velocity increase than normal (p < .05) and short poles (p < .05). This was in spite of a larger mean anterior-posterior reaction force being produced with short poles. Thus, thrust phase duration was a primary factor in determining propulsive anterior-posterior impulse. For the practitioner, the results can be useful in the selection of pole length when the aim is to increase thrust phase duration, anterior-posterior force impulse and velocity.  相似文献   

14.
运用CYBEX NORM等速测力系统,对两名健将级女子速滑运动员左、右腿髋、膝、踝三关节的屈、伸肌群进行了向心运动形式的肌力测试,并根据需要对左、右腿膝关节还进行了等速离心测试,以便找出两人运动学差异的内在动力学原因,为改进技术提供动力学依据。同时描述了速滑运动员髋关节、膝关节和踝关节的力矩曲线特性,进行深入探讨。测试结果:两名运动员的髋关节肌力发展不平衡;快速运动中,二人膝屈肌的肌力水平较差;二人踝关节伸肌群在适应较快速度收缩能力方面较差。  相似文献   

15.
The objective of this study was to develop and evaluate a methodology for quantifying the contributions of modelling error terms, as well as individual joint torque, gravitational force and motion-dependent terms, to the generation of ground reaction force (GRF), whose true value can be measured with high accuracy using a force platform. Dynamic contributions to the GRF were derived from the combination of (1) the equations of motion for the individual segments, (2) the equations for constraint conditions arising from the connection of adjacent segments at joints, and (3) the equations for anatomical constraint axes at certain joints. The contribution of the error term was divided into four components caused by fluctuation of segment lengths, geometric variation in the constraint joint axes, and residual joint force and moment errors. The proposed methodology was applied to the running motion of thirteen rear-foot strikers at a constant speed of 3.3?m/s. Modelling errors arose primarily from fluctuations in support leg segment lengths and rapid movement of the virtual joint between the foot and ground during the first 20% of stance phase. The magnitudes of these error contributions to the vertical and anterior/posterior components of the GRF are presented alongside the non-error contributions, of which the joint torque term was the largest.  相似文献   

16.
通过对两名高水平女子链球运动员双侧的髋关节和膝关节进行等速测试,探究运动员髋关节和膝关节周围肌群的生物力学特性,为运动训练和运动康复等提供理论依据。利用等速肌力测试系统对两名运动员的髋关节和膝关节屈伸肌群以及髋关节的旋内旋外肌群进行等速测试。结果发现:两名运动员双侧髋关节和膝关节屈伸肌群以及髋关节的旋内旋外肌群的峰力矩随测试速度的增加呈递减趋势,髋膝关节峰力矩屈伸比和髋关节旋内旋外比随既定测试速度的增加呈递增趋势;同一测试速度下,伸肌肌群的峰力矩大于屈肌肌群,髋关节旋外肌群的峰力矩大于旋内肌群。  相似文献   

17.
撑杆跳高运动插斗处动态力的测试受到多种因素的影响，分析测力平台在测试中的受力状态，指出装置的设计中应重点考虑装置的实用性，分析其刚性、质量及阻尼的影响，在最大限度简化结构的基础上提高其测试精度。  相似文献   

18.
Skiing     
The purpose of the investigation was to study the relationship between thrust phase duration, ground reaction force, velocity increase after pole thrust and pole angles versus pole length during double poling in roller skiing. Seven male regional elite cross‐country skiers volunteered as subjects for the study. The subjects performed a maximal double pole thrust on roller skis with each of the three different pole lengths: ‘short’, self‐selected (normal) and ‘long’. The short and long poles were 7.5 cm shorter and 7.5 cm longer than the self‐selected pole length. The subjects made seven maximal pole thrusts with each pole length, which were randomly selected during 21 trials. For each trial the subjects accelerated from a 1.2 m high downhill slope attaining a speed of 3.92 m.s‐1 before making a maximal double pole thrust on a force plate placed at the bottom of the slope. The vertical (Fz), anterior‐posterior (Fy) and medio‐lateral (Fx) reaction forces of the left pole were measured by the force plate. The positions of the pole were recorded in 3‐D by an opto‐electronic system. Thrust phase duration, impulse, mean force, velocity increase after pole thrust and pole angles were calculated from the recorded data. Double poling with long poles produced a significantly larger propulsive anterior‐posterior reaction force impulse and velocity increase than normal (p < .05) and short poles (p < .05). This was in spite of a larger mean anterior‐posterior reaction force being produced with short poles. Thus, thrust phase duration was a primary factor in determining propulsive anterior‐posterior impulse. For the practitioner, the results can be useful in the selection of pole length when the aim is to increase thrust phase duration, anterior‐posterior force impulse and velocity.  相似文献   

19.
Muscle power patterns in the mid-acceleration phase of sprinting   总被引：3，自引：2，他引：1  
To assess the role of the lower limb joints in generating velocity in the mid-acceleration phase of sprinting, muscle power patterns of the hip, knee and ankle were determined. Six male sprinters with a mean 100 m time of 10.75 s performed repeated maximal sprints along a 35 m indoor track. A complete stride across a force platform, positioned at approximately 14 m into the sprint, was video-recorded for analysis. Smoothed coordinate data were obtained from manual digitization of (50 Hz) video images and were then interpolated to match the sampling rate of the recorded ground reaction force (1000 Hz). The moment at each joint was then calculated using inverse dynamics and multiplied by the angular velocity to determine the muscle power. The results showed a proximal-to-distal timing in the generation of peak extensor power during stance at the hip, the knee and then the ankle, with the plantar flexors producing the greatest peak power. Apart from a moderate power generation peak towards toe-off, knee power was negligible despite a large extensor moment throughout stance. The role of the knee thus appears to be one of maintaining the centre of mass height and enabling the power generated at the hip to be transferred to the ankle.  相似文献   

20.
Diagonal skiing as a major classical technique has hardly been investigated over the last two decades, although technique and racing velocities have developed substantially. The aims of the present study were to 1) analyse pole and leg kinetics and kinematics during submaximal uphill diagonal roller skiing and 2) identify biomechanical factors related to performance. Twelve elite skiers performed a time to exhaustion (performance) test on a treadmill. Joint kinematics and pole/plantar forces were recorded separately during diagonal roller skiing (9°; 11 km/h). Performance was correlated to cycle length (r = 0.77; P < 0.05), relative leg swing (r = 0.71), and gliding time (r = 0.74), hip flexion range of motion (ROM) during swing (r = 0.73) and knee extension ROM during gliding (r = 0.71). Push-off demonstrated performance correlations for impulse of leg force (r = 0.84), relative duration (r = ? 0.76) and knee flexion (r = 0.73) and extension ROM (r = 0.74). Relative time to peak pole force was associated with performance (r = 0.73). In summary, diagonal roller skiing performance was linked to 1) longer cycle length, 2) greater impulse of force during a shorter push-off with larger flexion/extension ROMs in leg joints, 3) longer leg swing, and 4) later peak pole force, demonstrating the major key characteristics to be emphasised in training.  相似文献   

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