Relationship between Achilles tendon properties and foot strike patterns in long-distance runners

The purpose of this study was to investigate the relationship between Achilles tendon properties and foot strike patterns in long-distance runners. Forty-one highly trained male long-distance runners participated in this study. Elongation of the Achilles tendon and aponeurosis of the medial gastrocnemius muscle were measured using ultrasonography, while the participants performed ramp isometric plantar flexion up to the voluntary maximum. The relationship between the estimated muscle force and tendon elongation during the ascending phase was fit to a linear regression, the slope of which was defined as stiffness. In addition, the cross-sectional area of the Achilles tendon was measured using ultrasonography. Foot strike patterns (forefoot, midfoot and rearfoot) during running were determined at submaximal velocity (18 km · h^?1) on a treadmill. The number of each foot strike runner was 12 for the forefoot (29.3%), 12 for the midfoot (29.3%) and 17 for the rearfoot (41.5%). No significant differences were observed in the variables measured for the Achilles tendon among the three groups. These results suggested that the foot strike pattern during running did not affect the morphological or mechanical properties of the Achilles tendon in long-distance runners.     

Forefoot running requires shorter gastrocnemius fascicle length than rearfoot running

ABSTRACT

This study aimed to investigate the influence of foot strike patterns on the behaviour of the triceps surae muscle-tendon unit, including the Achilles tendon whose length nearly corresponds to force of the triceps surae, and the medial gastrocnemius muscle (MG) during running. Seven male volunteers ran with forefoot and rearfoot strikes at 10, 14 and 18 km h^?1 on a treadmill. The MG fascicle length was measured using ultrasonography. The in vivo length of the curved Achilles tendon was quantified by combining ultrasonography with optical motion capture of reflective markers on the right lower limb and an ultrasound probe. The forefoot strike resulted in a significantly shorter MG fascicle length at the initial contact, at Achilles tendon peak elongation, and at toe-off, than the rearfoot strike. The Achilles tendon length at initial contact was greater during the forefoot strike than during the rearfoot strike at 18 km h^?1, while its peak elongation was not significantly different during forefoot and rearfoot running. These results indicate that the MG, with a shorter length during forefoot running, manages to address demands for a similar peak force of the triceps surae than during rearfoot running.     

优秀女子体操运动员肩关节屈伸肌群的肌力特征研究

为研究体操运动员肩关节肌肉力量,采用美国研制的CyBex-6000型测力仪,对我国17名女子体操运动员右肩关节进行屈伸肌群的等动向心收缩测试(60°/s、240°/s)。受试者包括国际健将级4名、国家健将级6名和国家一级7名。比较受试者的肌力水平表明,运动水平高的运动员肩关节肌肉力量较高。本研究获得了不同等级的运动员肩关节屈伸肌群的基础数据,为体操运动员的力量训练及康复医疗提供理论依据。     

跳跃运动员膝关节屈伸肌群等速向心收缩时肌力与sEMG变化特征

采用ISOMED2000等速测力系统、ME6000无线肌电遥测系统,同步测试优秀跳跃运动员膝关节屈伸肌群在不同速度向心收缩过程中肌肉组织的力学及肌电活动特性.发现,跳跃运动员膝关节屈伸肌群在60°/s、180°/s、300°/s向心用力时力矩、功随着速度增加逐渐下降,而功率随速度增大而增加(P<0.01).sEMG显示,伸肌和屈肌均被最大程度地动员,且伸肌肌电各参数普遍高于屈肌.iEMG随速度增加而下降,RMS、MF和MPF均随运动速度增加而增加.力矩一功率关系以及功率-iEMG关系的相关性分析表明,在快速运动时,功率与力矩呈不显著性相关(P>0.05),而与iEMG呈高度相关(P<0.01).等速测试与肌电结合可作为监测与评价运动员膝关节神经肌肉交互活动的有效方法.     

沙滩排球训练对女排运动员弹跳肌群等速向心收缩肌力影响的比较研究

为探讨在沙滩这种特殊的介质上进行排球训练对运动员膝、踝关节肌群肌力的影响．在1998年沙滩排球训练周期前后．对我国12名兼职沙滩女排运动员的膝、踩关节屈伸肌群进行了等速向心收缩肌力测试。结果表明。沙滩训练后．膝关节屈肌群快肌纤维的爆发力．伸肌群快肌纤维的最大肌力和爆发力,踝关节跖肌群慢、快肌纤维的最大肌力和爆发力增长有显性意义。这是沙滩训练后原地纵跳成绩提高的重要肌力原因。     

大学生短跑运动员膝关节肌等速向心收缩的肌力研究

采用德国Isomed2000等速肌力测试系统、ME6000无线肌电遥测系统,同步测试优秀大学生短跑运动员膝关节屈伸肌群在不同速度向心收缩过程中肌肉组织的力学及肌电活动特性。结果显示：大学生短跑运动员膝关节屈伸肌群在60b／s、120b／s、240b／s向心用力时峰力矩随着速度增加逐渐下降;iEMG随着角速度的增加而下降;运动员左右腿屈、伸峰力矩比值接近运动员的正常范围,发展较均衡。     

踝关节跖屈肌肌肉肌腱形态及收缩效应的相关研究

应用螺旋CT及体视学研究方法对普通大学生踝关节跖屈肌肌肉肌腱形态进行了较全面的测量分析,同时采用六维测力平台结合表面肌电测量仪测定最大跖屈力,探讨跖屈肌肌肉肌腱形态与收缩效应之间的关系。结果表明:①小腿跖屈肌横断面积、体积和小腿围度与肌肉力量之间存在密切的关系;②小腿长、腓肠肌长、比腓肠肌肌腱长与肌力有着明显的相关;比目鱼肌长只与提踵肌力有关;③跟腱长、比跟腱长和腓肠肌肌腱长与肌力之间不具相关性。     

男子跳高一二级运动员髋关节肌力特征对比研究

采用等速测力实验等研究方法，对男子跳高一二级运动员髋关节肌力进行测试分析。发现两者表现出以下肌力平衡特征：一级运动员髋关节的肌力特征与跳高起跳技术用力特点相一致，即摆动腿髋关节屈肌力显著大于起跳腿，屈肌缺失值和伸肌缺失值较大；摆动腿髋关节屈伸比大、起跳腿小。而二级运动员髋关节肌力矩未表现出此特征。     

Connective tissue adaptations in the fingers of performance sport climbers

Abstract

This study investigates the changes of the connective tissue in the fingers of performance sport climbers resulting after a minimum of 15 years of climbing. Evaluation was performed by ultrasonography on the palmar side of the fingers (Dig) II–V to measure the thickness of the A2 and A4 annular pulleys, the flexor digitorum superficialis (FDS) and profundus (FDP) tendons and the palmar plates (PP's) of the proximal interphalangeal (PIP) as well as distal interphalangeal (DIP) joint in sagittal and axial direction. Totally, 31 experienced male sport climbers (mean age 37y, 30–48y grade French scale median 8b, range 7b+ to 9a+) participated in the study. The control-group consisted of 20 male non-climbers (age 37y, 30–51y). The A2 and A4 pulleys in climbers were all significantly thicker (A2 Dig III 62%, Dig IV 69%; A4 Dig III 69%, Dig IV 76%) as compared to non-climbers pulleys. All PP's of the DIP joints were also significantly thicker, particularly at Dig III and IV (76 and 67%), whereas the PP's at PIP joints were only scarce significant for three joints. Differences of the diameter of the flexor tendons were less distinct (1–21%) being significant only over the middle phalanx. High load to the fingers of rock climbers after a minimum of 15 years of climbing years induced considerable connective tissue adaptions in the fingers, most distinct at the flexor tendon pulleys and joint capsule (PP) of the DIP joints and well detectable by ultrasound.     

影响短跑运动员运动成绩的要因

通过等动测力系统对短跑运动员在角速度为60°/s、180°/s及300°/s的膝关节和髋关节伸、屈肌峰力矩进行了测试,并就测试结果与不同距离短跑成绩之间的相关性进行了探讨,发现不同角速度的伸肌峰力矩均明显高于屈肌峰力矩,同时也发现100m加速跑成绩相关最显著的是角速度为300°/s时膝关节伸肌力矩和180°/s时髋关节伸肌力矩.