不同踢球方式摆动腿的运动学与肌电信号特征研究

为研究脚背内侧踢球、脚背正面踢球、脚内侧踢球以及脚背外侧踢球4种基本踢球方式摆动腿的运动学和肌肉力学特征,获取人体运动内外信息,运用三维运动学分析与表面肌电信号特征分析的方法对其研究发现,4种基本踢球方式摆动腿的摆动时间、摆动幅度以及摆动速度均表现出不同特点;后摆阶段摆动腿肌群的兴奋程度表现出了较好的一致性,而前摆阶段摆动腿肌群的兴奋程度表现出了较大差异性;此外,股二头肌在前摆阶段对关节的控制程度与踢球精度间存在一定相关性。     

优势脚与非优势脚正脚背踢球的运动学特征对比研究

足球运动中踢球脚有优势脚与非优势脚之分,优势脚踢球主要表现为踢球力量大、出球准确,而非优势脚则与之相反。两者摆动腿摆动特征具有相似性,但运用生物力学手段对其研究发现,优势脚与非优势脚摆动腿的摆动特征存在很多差异性,主要表现在非优势脚摆动腿的蹬地不充分、股后肌群力量较弱、小腿屈曲不充分、小腿前摆时间过早、膝关节制动太早以及小腿前摆不充分等一系列差异上。因此,平时应该加强非优势脚训练,以形成正确动力定型。     

足球运动中不同踢球方式摆动腿的运动学特征比较与分析

踢球是决定比赛胜负的主要技术手段之一.其中,脚背内侧踢球、正脚背踢球、脚内侧踢球及脚背外侧踢球是4种最基本的踢球方法.4种踢球方法踢球腿的摆动具有相似性,运动生物力学手段对其进行研究比较发现,脚背内踢球摆动腿的大腿前摆角最大,脚内侧踢球小腿前摆角最小,脚触球时,正脚背踢球与脚背外侧踢球的小腿角速度最快,脚内侧最慢.摆动腿的摆动存在鞭打动作,但不仅仅局限于鞭打动作.     

短跑运动员摆动腿前摆动作迟缓及产生原因

本文通过对短跑运动员途中跑过程中摆动腿前摆动作迟缓进行了理论分析，认为支撑腿后蹬过直，踝关节肌群离心与向心收缩能力差，以及大腿股后肌群快速收缩力量簿弱，是造成摆动腿前摆动作迟缓的主要因素。针对这一问题，本文提出一些克服摆动腿前摆动作迟缓的训练方法。     

足球运动踢球腿摆动阶段的不同时相运动特征

运用生物力学手段对5名高水平足球运动员摆动腿进行研究发现:根据摆动腿环节摆动顺序与环节摆动速度相结合的方法可将其划分为用力蹬伸、主动后摆、大腿前摆、小腿前摆,脚触球5个阶段.其中,用力蹬伸阶段是不可忽视的重要阶段之一,主动后摆阶段摆动腿应在不影响前摆速度的前提下尽力后摆;大腿前摆阶段摆动腿应在大腿摆到一定幅度时进行积极制动,摆动幅度不宜过大;小腿前摆阶段摆动腿除了膝关节的积极制动外还应主动施力.     

短跑运动员摆动腿前摆动作迟缓及产生原因

短跑运动员在跑动中摆动腿前摆动作迟缓,主要表现在两个方面:一是支撑腿后蹬转换为前摆的时间较长;二是摆动腿前摆速度缓慢。支撑与摆动是短跑中相互交替的两个动作,而摆动腿前摆的速度是人体获得向前运动的重要动力。在教学与训练中,大都采用抗阻力摆腿的练习方法,增大髋屈肌群的收缩力量,以达到提高摆动腿前摆速度的目的。从训练实践中我们得知,髋屈肌群力量的增长并非与前摆的速度成正比,摆动腿前摆的速度不仅与髋屈肌群收缩力量有关,而且     

浅析短跑训练中的放松训练

一、短跑技术中肌肉放松的作用 肌肉放松能减小肢体的转动惯量,提高摆动角速度,提高频率。短跑中,从腿后蹬地结束脚离地面开始的屈膝前摆,是先屈膝关节,后屈髋关节。屈膝关节时,若充分放松傅展股肢肌,股内侧肌,股外侧肌,股中间肌就更有利于股后群肌肉坐近固定时向心收缩工作,使小腿靠近大腿折叠,缩短了向前摆腿的距离,使整个下肢绕髋关节轴的转动惯量减小,     

短跑运动员缩小大腿后摆幅度的练习方法

大腿后摆幅度是指支撑腿后蹬时,大腿随后蹬惯性向后摆动动作的大小。我们知道,现代短跑技术应视为以髋关节为轴的高速摆动,十分注重大腿前摆的效果即大腿前摆的速度、力量和幅度。那么如何提高大腿前摆的效果呢?许多人认为增大摆动腿主动肌群快速收缩的力量,是提高大腿前摆效果的有效途径。然而对于大腿后摆的幅度与其向前摆动时所产生的影响,似乎还没引     

不同高度脚背正面射门动作的生物力学特征

为揭示不同高度脚背正面射门的生物力学机制。招募12名受试者对地面球、1/2膝关节高、膝关节高3种位置进行脚背正面射门和空踢各10次。利用2台JVC9800摄像机、国产JP6060多维测力平台进行运动学及动力学同步测量。结果显示:地面球、1/2膝关节及全膝关节3种高度射门,球速、足速经多因素方差分析均有显著差异,其中地面球球速最快、1/2膝关节高度次之、膝关节高最小;实验组受试者摆动腿大腿前摆与后摆、小腿后摆等各运动学指标在不同高度位置射门间无显著性差异,而小腿前摆运动学数据在不同高度射门间存在显著性差异;支撑腿与球垂直距离跟各高度射门的球速、摆动腿足速度、触球即刻膝角、小腿前摆角速度、小腿前摆幅度、小腿前摆时间呈显著相关,而3种高度位置的射门球速与支撑腿着地所受地面反作用力不存在线性关系。结果说明:脚背正面射门击球点高度越低球速越快,故脚背正面射门想要获取更快球速就应该在球高度处于较低位置时将球踢出;通过控制支撑腿与球垂直距离可以控制脚背正面射门的球速、球路、动作时间;支撑腿受到的地面反作用力与踢出球的球速无关,故支撑腿在踢球过程中的主要作用是固定支撑、维持平衡,从而使摆动腿发力更加充分。     

短跑途中跑臀部后坐对跑速的不利影响

臀部后坐是短跑运动员在途中跑时较为常见的一种不合理的跑动技术,其技术动作的不合理性表现在下肢的支撑与摆动动作上。由于臀部后坐,支撑腿从着地缓冲转变为后蹬,髋部伸展的速度与幅度降低,削弱髋关节的用力程度,使后蹬力量得不到充分地发挥。随着髋部伸展速度的降低,髋屈肌群被拉长的速度缓慢。当支撑腿后蹬结束再转换为前摆时,快速收缩的力量减退,不能有力地带动大腿快速前摆,导致摆动腿前摆动作迟缓。在跑动中容易造成蹬地腿与摆动腿配合不协调,达不到以摆促蹬、蹬摆结合的效果。那么,蹬伸与摆动所产生的力量不能有效地促进身体重心向水平方向快速移动,从而延长了支撑时间,对跑速的增长产生一些不利的影响。主要影响有以下几个方面。     

Dynamics of the support leg in soccer instep kicking

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.     

Dynamics of submaximal effort soccer instep kicking

During a soccer match, players are often required to control the ball velocity of a kick. However, little information is available for the fundamental qualities associated with kicking at various effort levels. We aimed to illustrate segmental dynamics of the kicking leg during soccer instep kicking at submaximal efforts. The instep kicking motion of eight experienced university soccer players (height: 172.4 ± 4.6 cm, mass: 63.3 ± 5.2 kg) at 50, 75 and 100% effort levels were recorded by a motion capture system (500 Hz), while resultant ball velocities were monitored using a pair of photocells. Between the three effort levels, kinetic adjustments were clearly identified in both proximal and distal segments with significantly different (large effect sizes) angular impulses due to resultant joint and interaction moments. Also, players tended to hit an off-centre point on the ball using a more medial contact point on the foot and with the foot in a less upright position in lower effort levels. These results suggested that players control their leg swing in a context of a proximal to distal segmental sequential system and add some fine-tuning of the resultant ball velocity by changing the manner of ball impact.     

Contributions of the non-kicking-side arm to rugby place-kicking technique

To investigate non-kicking-side arm motion during rugby place kicking, five experienced male kickers performed trials under two conditions, both with an accuracy requirement but one with an additional maximal distance demand. Joint centre coordinates were obtained at 120 Hz during kicking trials and a three-dimensional model was created to enable the determination of segmental contributions to whole-body angular momentum. All kickers possessed minimal non-kicking-side arm angular momentum about the global medio-lateral axis. The more accurate kickers exhibited greater non-kicking-side arm angular momentum about the global antero-posterior axis. This augmented the whole-body antero-posterior angular momentum, and altered the whole-body lateral lean at ball contact. The accurate kickers also exhibited greater non-kicking-side arm angular momentum about the global longitudinal axis, which opposed the kicking leg longitudinal angular momentum and attenuated the whole-body longitudinal angular momentum. All participants increased the longitudinal angular momentum of the non-kicking-side arm in the additional distance demand condition, except for one participant whose accuracy decreased, suggesting that the longitudinal angular momentum of the non-kicking-side arm assists maintenance of accuracy in maximum distance kicking. Goal kickers should be encouraged to produce non-kicking-side arm rotations about both the antero-posterior and longitudinal axes, as these appear important for both the initial achievement of accuracy, and for maintaining accuracy during distance kicking.     

Segmental dynamics of soccer instep kicking with the preferred and non-preferred leg

Detailed time-series of the resultant joint moments and segmental interactions during soccer instep kicking were compared between the preferred and non-preferred kicking leg. The kicking motions of both legs were captured for five highly skilled players using a three-dimensional cinematographic technique at 200 Hz. The resultant joint moment (muscle moment) and moment due to segmental interactions (interaction moment) were computed using a two-link kinetic chain model composed of the thigh and lower leg (including shank and foot). The mechanical functioning of the muscle and interaction moments during kicking were clearly illustrated. Significantly greater ball velocity (32.1 vs. 27.1 m . s(-1)), shank angular velocity (39.4 vs. 31.8 rad . s(-1)) and final foot velocity (22.7 vs. 19.6 m . s(-1)) were observed for the preferred leg. The preferred leg showed a significantly greater knee muscle moment (129.9 N . m) than the non-preferred leg (93.5 N . m), while no substantial differences were found for the interaction moment between the two legs (79.3 vs. 55.7 N . m). These results indicate that the highly skilled soccer players achieved a well-coordinated inter-segmental motion for both the preferred and non-preferred leg. The faster leg swing observed for the preferred leg was most likely the result of the larger muscle moment.     

The effect of muscle fatigue on instep kicking kinetics and kinematics in association football

The aim of this study was to examine the effect of leg muscle fatigue on the kinetics and kinematics of the instep football kick. Fatigue was induced by repeated, loaded knee extension (40% body weight) and flexion (50% body weight) motions on a weight-training machine until exhaustion. The kicking motions of seven male players were captured three-dimensionally at 500 Hz before and immediately after the fatigue protocol. The significantly slower ball velocity observed in the fatigue condition was due to both reduced lower leg swing speed and poorer ball contact. The reduced leg swing speed, represented by a slower toe linear velocity immediately before ball impact and slower peak lower leg angular velocity, was most likely due to a significantly reduced resultant joint moment and motion-dependent interactive moment during kicking. These results suggest that the specific muscle fatigue induced in the present study not only diminished the ability to generate force, but also disturbed the effective action of the interactive moment leading to poorer inter-segmental coordination during kicking. Moreover, fatigue obscured the eccentric action of the knee flexors immediately before ball impact. This might increase the susceptibility to injury.     

Contributions of the non-kicking-side arm to rugby place-kicking technique

To investigate non-kicking-side arm motion during rugby place kicking, five experienced male kickers performed trials under two conditions, both with an accuracy requirement but one with an additional maximal distance demand. Joint centre coordinates were obtained at 120 Hz during kicking trials and a three-dimensional model was created to enable the determination of segmental contributions to whole-body angular momentum. All kickers possessed minimal non-kicking-side arm angular momentum about the global medio-lateral axis. The more accurate kickers exhibited greater non-kicking-side arm angular momentum about the global antero-posterior axis. This augmented the whole-body antero-posterior angular momentum, and altered the whole-body lateral lean at ball contact. The accurate kickers also exhibited greater non-kicking-side arm angular momentum about the global longitudinal axis, which opposed the kicking leg longitudinal angular momentum and attenuated the whole-body longitudinal angular momentum. All participants increased the longitudinal angular momentum of the non-kicking-side arm in the additional distance demand condition, except for one participant whose accuracy decreased, suggesting that the longitudinal angular momentum of the non-kicking-side arm assists maintenance of accuracy in maximum distance kicking. Goal kickers should be encouraged to produce non-kicking-side arm rotations about both the antero-posterior and longitudinal axes, as these appear important for both the initial achievement of accuracy, and for maintaining accuracy during distance kicking.     

Adductor longus mechanics during the maximal effort soccer kick

Groin pain is a common cause of athletic disability and often involves the adductor longus. A common complaint of patients with groin problems is pain while preparing to kick the ball. The purpose of this study was to examine muscle length and activation of the adductor longus while kicking a soccer ball. Three-dimensional joint positions and muscle activation were obtained from 15 National Collegiate Athletic Association (NCAA) Division 1 male soccer players during maximal effort kicks. Musculoskeletal modeling techniques incorporating joint position and muscle attachments were used to estimate adductor longus length from the beginning of the kicking leg's swing phase until ball strike. The maximum rate of stretch of the adductor longus (22.3 ± 5.3 cm/s) and maximum hip extension (23.3 ± 8.8°) occurred near 40% of swing phase. Activation of the adductor longus occurred between 10% and 50% of the swing phase. Adductor longus maximum length occurred at 65% of the swing phase. Maximum hip abduction (25.3 ± 5.4°) occurred at 80% of swing phase. The adductor longus appears to be at risk of strain injury during its transition from hip extension to hip flexion. This knowledge could be applied to muscle injury prevention and rehabilitation programs to aid with treatment of adductor longus related groin pain.