共查询到20条相似文献，搜索用时 15 毫秒
1.
Execution time, kinetics, and kinematics of the mae-geri kick: comparison of national and international standard karate athletes 总被引：1，自引：1，他引：0
Little is known of the performance characteristics of the shotokan karate mae-geri kick. The aim of this study was to compare the execution time, the lower limb kinetics and kinematics, and their respective repeatability in the mae-geri kick of karate athletes of two different standards. Seventeen adult black belt karate competitors (9 national and 8 international athletes) performed six kicks with their dominant lower limb on a striking surface, combining maximum force impact and velocity. Execution time of movement and lower limb kinematics were recorded with a high-speed camera. Maximum force at impact and the forces exerted on the ground were measured using three force plates. The duration of the kick was significantly shorter for international than for national standard athletes. However, no significant difference in the maximum impact force of the kick was observed between the two groups. In addition, significant kinematic differences were observed between the groups, with two angles of motion and one velocity peak occurring sooner in the kick movement for the international athletes, specifically for the knee joint. International athletes also performed the kick with a significantly higher repeatability for duration and kinematics, specifically during the pre-loading phase that precedes the attack phase. We conclude that the duration of the kick and repeatability of lower limb kinematics could be useful in selecting top-level karate athletes and monitoring their training status. 相似文献
2.
Abstract Little is known of the performance characteristics of the shotokan karate mae-geri kick. The aim of this study was to compare the execution time, the lower limb kinetics and kinematics, and their respective repeatability in the mae-geri kick of karate athletes of two different standards. Seventeen adult black belt karate competitors (9 national and 8 international athletes) performed six kicks with their dominant lower limb on a striking surface, combining maximum force impact and velocity. Execution time of movement and lower limb kinematics were recorded with a high-speed camera. Maximum force at impact and the forces exerted on the ground were measured using three force plates. The duration of the kick was significantly shorter for international than for national standard athletes. However, no significant difference in the maximum impact force of the kick was observed between the two groups. In addition, significant kinematic differences were observed between the groups, with two angles of motion and one velocity peak occurring sooner in the kick movement for the international athletes, specifically for the knee joint. International athletes also performed the kick with a significantly higher repeatability for duration and kinematics, specifically during the pre-loading phase that precedes the attack phase. We conclude that theduration of the kick and repeatability of lower limb kinematics could be useful in selecting top-level karate athletes and monitoring their training status. 相似文献
3.
Wilson C Simpson SE van Emmerik RE Hamill J 《Sports biomechanics / International Society of Biomechanics in Sports》2008,7(1):2-9
The aim of this study was to examine the influence of skill of expert triple jumpers on the coordination variability of lower extremity intra-limb couplings. In contrast to the traditional motor learning perspective, we hypothesized that as skill and thus performance increases, movement coordination variability will also increase. Three-dimensional kinematic and ground reaction force data were collected during the hop-step transition phase of the triple jump. Relative motion plots and a modified vector coding technique were used to quantify the coordination variability across the trials. The results were consistent with a U-shaped curve, representing coordination variability, as skill increases. The high coordination variability in less skilled athletes is present while the appropriate characteristics defining the movement coordination patterns are acquired. This coordination variability may not be beneficial to performance. As the refinement of these characteristics is achieved, coordination variability decreases, resulting in a more consistent or regulated performance. In the final stages of developing a skilled performance, a functional variability is accessed that brings flexibility to the system allowing it to cope with perturbations. This study highlights the need to address the learning effect when analysing coordination variability from a dynamical systems perspective. 相似文献
4.
李继辉 《沈阳体育学院学报》2007,26(1):68-70
采用文献资料、问卷调查、立体定点定机摄像与解析、逻辑分析和数理统计等方法,对中国优秀竞走运动员的技术风格和技术动作进行全面分析,以期为教练员、科研人员和运动员提供有益的参考。研究认为:我国优秀男子、女子竞走运动员目前的技术特点仍是在采用高步频的竞走技术风格;我国优秀男子竞走运动员均采用“足踵触地、踝关节背屈”滚动式着地技术,以及后蹬腿脚尖离地技术,符合当今世界竞走运动发展趋势。 相似文献
5.
Giulia Donà Ezio Preatoni Claudio Cobelli Renato Rodano Andrew J. Harrison 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(4):284-301
This study considered the problem of identifying and evaluating the factors of individual performance during race walking. In particular, the study explored the use of functional principal component analysis (f-PCA), a multivariate data analysis, for assessing and classifying the kinematics and kinetics of the knee joint in competitive race walkers. Seven race walkers of international and national level participated to the study. An optoelectronic system and a force platform were used to capture three-dimensional kinematics and kinetics of lower limbs during the race walking cycle. Functional principal component analysis was applied bilaterally to the sagittal knee angle and net moment data, because knee joint motion is fundamental to race walking technique. Scatterplots of principal component scores provided evidence of athletes' technical differences and asymmetries even when traditional analysis (mean ± s curves) was not effective. Principal components provided indications for race walkers' classification and identified potentially important technical differences between higher and lower skilled athletes. Therefore, f-PCA might represent a future aid for the fine analysis of sports movements, if consistently applied to performance monitoring. 相似文献
6.
Bartlett R Wheat J Robins M 《Sports biomechanics / International Society of Biomechanics in Sports》2007,6(2):224-243
This paper overviews the importance for sports biomechanics of movement variability, which has been studied for some time by cognitive and ecological motor skills specialists but, until quite recently, had somewhat been overlooked by sports biomechanists. The paper considers biomechanics research reporting inter- and intra-individual movement variability in javelin and discus throwing, basketball shooting, and locomotion. The overview does not claim to be comprehensive and we exclude such issues as the theoretical background to movement and coordination variability and their measurement. We overview evidence, both theoretical and empirical, of inter-individual movement variability in seeking to achieve the same task goal, in contrast to the concept of "optimal" movement patterns. Furthermore, even elite athletes cannot reproduce identical movement patterns after many years of training, contradicting the ideas of motor invariance and "representative" trials. We contend that movement variability, far from being solely due to neuromuscular system or measurement "noise"--as sports biomechanists may have previously supposed--is, or could be, functional. Such functionality could allow environmental adaptations, reduce injury risk, and facilitate changes in coordination patterns. We conclude by recommending that sports biomechanists should focus more of their research on movement variability and on important related topics, such as control and coordination of movement, and implications for practice and skill learning. 相似文献
7.
竞走速度是所有关于竞走运动技术和特征研究的首要问题,也是所有竞速项目最终要解决的问题。运用文献资料法、数理统计法、逻辑分析法对12运会男子、女子20km前8名运动员的速度特征进行分析,探求中国竞走运动员速度发展的趋势以及存在的问题,为中国竞走运动员参加2015世界田径锦标赛和2016里约奥运会提供参考。 相似文献
8.
Roger Bartlett Jon Wheat Matthew Robins 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):224-243
This paper overviews the importance for sports biomechanics of movement variability, which has been studied for some time by cognitive and ecological motor skills specialists but, until quite recently, had somewhat been overlooked by sports biomechanists. The paper considers biomechanics research reporting inter- and intra-individual movement variability in javelin and discus throwing, basketball shooting, and locomotion. The overview does not claim to be comprehensive and we exclude such issues as the theoretical background to movement and coordination variability and their measurement. We overview evidence, both theoretical and empirical, of inter-individual movement variability in seeking to achieve the same task goal, in contrast to the concept of “optimal” movement patterns. Furthermore, even elite athletes cannot reproduce identical movement patterns after many years of training, contradicting the ideas of motor invariance and “representative” trials. We contend that movement variability, far from being solely due to neuromuscular system or measurement “noise” – as sports biomechanists may have previously supposed – is, or could be, functional. Such functionality could allow environmental adaptations, reduce injury risk, and facilitate changes in coordination patterns. We conclude by recommending that sports biomechanists should focus more of their research on movement variability and on important related topics, such as control and coordination of movement, and implications for practice and skill learning. 相似文献
9.
对我国优秀少年女子竞走运动员主要技术特征的运动学分析 总被引：4，自引：0，他引：4
赵俊龙 《沈阳体育学院学报》2004,23(6):766-768
采用摄像及录像解析等研究方法,对2002年"海尔斯"杯全国竞走锦标赛暨亚运会选拔赛少年女子5000米场地赛前3名运动员(年龄在17岁以下)的技术进行分析,分别拍摄每个运动员在比赛进行到1150米处、2750米处、4350米处的技术图片资料,并进行解析,以取得每个运动员一个复步的各个阶段和各个技术环节的定量数据。研究结果表明:有2名运动员的腾空时间超过了合理的腾空时限;单步身体重心垂直位移和头顶垂直位移均较大;躯干前倾后仰幅度较大;膝关节技术动作符合竞走定义的要求;运动员的足掌触地角较小。 相似文献
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11.
Abstract The aim of this study was to analyse lower limb joint moments, powers and electromyography patterns in elite race walking. Twenty international male and female race walkers performed at their competitive pace in a laboratory setting. The collection of ground reaction forces (1000 Hz) was synchronised with two-dimensional high-speed videography (100 Hz) and electromyography of seven lower limb muscles (1000 Hz). As well as measuring key performance variables such as speed and stride length, normalised joint moments and powers were calculated. The rule in race walking which requires the knee to be extended from initial contact to midstance effectively made the knee redundant during stance with regard to energy generation. Instead, the leg functioned as a rigid lever which affected the role of the hip and ankle joints. The main contributors to energy generation were the hip extensors during late swing and early stance, and the ankle plantarflexors during late stance. The restricted functioning of the knee during stance meant that the importance of the swing leg in contributing to forward momentum was increased. The knee flexors underwent a phase of great energy absorption during the swing phase and this could increase the risk of injury to the hamstring muscles. 相似文献
12.
我国优秀女子竞走运动员关键技术的生物力学研究 总被引：4，自引：0，他引：4
用１６ｍｍ高速摄影机进行比赛现场单步技术动作拍摄，拍摄频率为１２２幅／ｓ。采用国家体委体育科研所运动生物力学研究室影片解析系统，对国家竞走集训队运动员王妍、谷燕的竞走技术进行解析。研究结果，王妍、谷燕竞走技术符合国际田联新竞走定义。 相似文献
13.
Hanley B Bissas A Drake A 《Sports biomechanics / International Society of Biomechanics in Sports》2011,10(2):110-124
The aim of this study was to analyse the important kinematic variables in elite men's and women's 20 km race walking. Thirty men and 30 women were analysed from video data recorded during the World Race Walking Cup. Video data were also recorded at four points during the European Cup Race Walking and 12 men and 12 women analysed from these data. Two camcorders operating at 50 Hz recorded at each race for 3D analysis. The two main performance determinants of speed were step length and cadence. Men were faster than women because of their greater step lengths but there was no difference in cadence. A reduction in step length was the initial cause of slowing down with later decreases in speed caused by reductions in cadence. Shorter contact times were important in optimising both step length and cadence, and faster athletes tended to have longer flight times than slower athletes. It was less clear which other kinematic variables were critical for successful walking, particularly with regard to joint angles. Different associations were found for some key variables in men and women, suggesting that their techniques may differ due to differences in height and mass. 相似文献
14.
青少年竞走运动员的心理诊断 总被引：1，自引：0，他引：1
采用"福莱斯特心理负荷症状调查表 "对影响竞走运动员的竞赛心理因素进行测试和研究.结果说明:不同因素使不同性别、组别、年龄的竞走运动员参赛时的心理表现不同.各种不利因素的出现使运动员主要产生"这是我经常失败的原因"和"成绩总是不好"的心理.生理因素的影响是造成运动员经常失败的原因之一.认知因素和刺激因素的出现使运动员的心理表现主要为"这一情况对我无所谓",其次是"激励我去夺取优异成绩".影响成绩的因素主要为"失眠"、"情绪过于紧张"和"出师不利"、"自我感觉身体不适,竞技状态不佳". 相似文献
15.
The aim of this study was to analyse gait variability and symmetry in race walkers. Eighteen senior and 17 junior athletes race walked on an instrumented treadmill (for 10 km and 5 km, respectively) at speeds equivalent to 103% of season’s best time for 20 km and 10 km, respectively. Spatio-temporal and ground reaction force (GRF) data were recorded at 2.5 km, and at 4.5, 6.5 and 8.5 km for a subsection of athletes. Gait variability was measured using median absolute deviation (MAD) whereas inter-leg symmetry was measured using the symmetry angle. Both groups showed low variability for step length (<0.9%), step frequency (<1.1%), contact time (≤1.2%) and vertical peak force values (<5%), and neither variability nor symmetry changed with distance walked. Junior athletes were more variable for both step length (P = 0.004) and loading force (P = 0.003); no differences for gait symmetry were found. Whereas there was little mean asymmetry overall, individual analyses identified asymmetry in several athletes (symmetry angle ≥ 1.2%). Importantly, asymmetrical step lengths were found in 12 athletes and could result from underlying imbalances. Coaches are advised to observe athletes on an individual basis to monitor for both variability and asymmetry. 相似文献
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17.
Brian Hanley Athanassios Bissas Andrew Drake 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):110-124
The aim of this study was to analyse the important kinematic variables in elite men's and women's 20 km race walking. Thirty men and 30 women were analysed from video data recorded during the World Race Walking Cup. Video data were also recorded at four points during the European Cup Race Walking and 12 men and 12 women analysed from these data. Two camcorders operating at 50 Hz recorded at each race for 3D analysis. The two main performance determinants of speed were step length and cadence. Men were faster than women because of their greater step lengths but there was no difference in cadence. A reduction in step length was the initial cause of slowing down with later decreases in speed caused by reductions in cadence. Shorter contact times were important in optimising both step length and cadence, and faster athletes tended to have longer flight times than slower athletes. It was less clear which other kinematic variables were critical for successful walking, particularly with regard to joint angles. Different associations were found for some key variables in men and women, suggesting that their techniques may differ due to differences in height and mass. 相似文献
18.
竞走运动员技术犯规的生物力学成因的研究 总被引：27，自引：4，他引：23
采用高速摄影机定点拍摄了第17 届世界杯竞走赛各单项前8 名中外运动员的竞走技术,用江苏省体科所生产的“JTK-1”型影片解析系统对原始数据进行处理,依所得数据分析论述了造成竞走运动员技术犯规的生物力学成因 相似文献
19.
自由式滑雪空中技巧项目的落地所受冲击力较大,危险性较高。为减少运动员落地时造成损伤,提高动作的落地稳定性,采用瑞士KISTLER测力台和2台美国TROUBLESHOOTER高速摄像机,同步对6名国家自由式滑雪空中技巧男子运动员在50cm高度下以正常姿势落地和全脚掌落地缓冲实验,分析缓冲时间、标准力值、力值变化梯度、压力中心、人体倾斜角以及下肢关节角度等变化情况。结果表明,50cm高度下最大冲击力全脚掌为正常落地的1.44倍,极有可能造成人体损伤;压力中心前后方向上较小;人体倾斜角较大,说明产生的翻转力矩较小,故稳定性方面较好。 相似文献