优秀游泳运动员转身技术分析

本文指出,影响蛙泳转身效果主要因素是游进池壁二米的时间、团身时间及手脚触壁时间差。影响自由泳前滚翻转身效果的主要因素是游进池壁二米至两脚触壁的时间、蹬出时的髋角、蹬出速度、脚触壁至蹬出头至二米的时间。本研究中所获的数据对充实技术理论有较大的参考价值。     

游泳：内行的门道

游泳 一是看每次转身时距离池壁的距离。如果在转身触壁时肘部过度弯曲或脸部露出水面,说明运动员“划慢了”,这样会使蹬离池壁的力量和角度受到影响,打乱运动员的动作节奏,进而造成一定的心理压力。如果在转身前身体没入水中后良久才触壁,说明运动员没有控制好距离,会使触壁前的速度降低,影响转身的速度。一般来说,双臂和头部没入水中并且肩部伸展后即刻触壁,是较好的转身表现。     

浅谈游泳的转身动作

在游泳比赛中,转身动作的好坏直接影响游进的速度和成绩,转身好就有获胜的希望。据最近国内有关人员对运动员的转身动作进行定量分析研究后发现,我国优秀运动员的转身动作比国外优秀选手的转身动作要慢得多,尤其是蹬壁这个技术环节。这一结     

爬泳前滚翻转身技术的教学

目前国际自由泳比赛中越来越普遍地采用高速的前滚翻转身技术。实验证明:前滚翻转身从手触及池壁到脚蹬离池壁只要0.6—0.7秒,而其他转身要1.0—1.2秒,几乎可以快一倍。这在短距离比赛中常常是决定胜负的关键。前滚翻转身要求运动员保持速度游近池壁,低头同时以手插入水下15—25公分处触壁,屈体绕横轴前滚至上体接近垂直水面时推壁。这时,运动员同时绕两个轴旋转,一方面继续屈髋关节,并屈膝团身,一方面通过肩带转动绕纵轴滚转成侧卧,双脚上下触壁,大小腿成锐角,两臂前伸夹头并蹬离池壁,再逐渐转成俯卧,开始游泳动作。前滚翻转身技术的优越性在于转身时能充分地利用运动员身体前进的惯性力,在转身的刹那间又     

游泳中双手双脚重叠并拢滑行技术分析

本文通过游泳训练教学的实践,根据运动生物力学原理和人在水中游进时滑行的特点,为提高游泳运动员出发和转身后的水中滑行速度,从而能够提高游泳运动员的竞赛成绩,对游泳中双手双脚重叠并拢滑行技术进行初步的研究探索其可行性。经研究分析得出,采用双手双脚重叠并拢滑行技术能够直接提高出发,转身,蹬边的速度,效果较为明显。通过此技术的应用,能直接提高竞技游泳各项目的运动成绩。     

出发、转身和终点触壁技术

你可能多次听人讲：“他出发慢了,再也追不上了”,或“他输在转身上了”,或“他触壁慢了”。这种话听得太多了。虽说都知道出发、转身和终点触壁技术何等重要,但是我们在训练中往往顾此失彼,忽略了出发、转身和触壁技术的练习。无论是陆上,还是水上练习,甚至做打腿练习,每次进行蹬边、滑行、转身和触壁练习,都有机会改进这些对比赛胜负有绝对意义的技术。     

孙杨备战伦敦奥运会转身技术改进与优化的生物力学研究

孙杨中长距离自由泳2009—2011年重大比赛的转身15m(RTT15)技术资料显示,转身技术的改进与优化,是孙杨备战2012年伦敦奥运会进一步提高成绩的重点技术环节之一。将测力板安装在泳池转身蹬壁处,在国内首次应用转身蹬壁专项力量水下测量与水下摄像解析同步分析方法,研究孙杨转身过程的技术特点和存在问题。结果表明,转身过程团身速度较慢、幅度过小及动作不够连贯协调,影响蹬壁发力效果,是孙杨转身技术存在的主要问题。至2012年5月的跟踪研究资料显示,孙杨团身幅度明显加大、团身速度显著提高、团身至蹬壁发力整个技术动作的连贯协调性明显改进。     

Y_Z-B型游泳转身测试仪的研制及应用

选题依据转身技术是游泳技术中的重要组成部分,也是我国优秀游泳运动员普遍存在的薄弱环节。过去教练及科研人员通常采用目测或用秒表计时的方法测量转身时间,评价转身技术动作,既不够准确,也很难确切指出存在的问题。为了给运动训练实践提供一种客观的定量化检测手段,我们研制了Y_Z-B型测试仪。仪器的用途本仪器主要应用于测量游泳运动员转身动作和转身过程的各环节的时间,包括:游近池壁5米,准备转身前3米,触、蹬壁的时间和蹬离池壁至8或15米的时间。仪器设计思想四种游泳姿势有三类不同的转身技术。自由泳是     

《游泳规范技术图解》征订中英、中俄对照

根据近年美国、俄罗斯、加拿大和乌克兰出版的游泳著作中刊登的世界优秀选手规范技术照片、图片,按其各种泳式游进、出发、转身和终点触壁典型动作编辑的这部著作共收录120余套,600余幅照片和图片。这些图片、照片反映了当前世界最先进的游泳规范技术,可供体育院校学生、各种水平的运动员及家长、游泳爱好者、教练员学习改进游泳技术时参阅。     

游泳技术文摘

自由泳蹬离池壁后的双臂划水技术短距离自由泳的转身技术对运动员转身后获得最大冲力起着重要的作用。我们发现,将以往传统的转身蹬边后一手前伸,一手往后划水的第一次配合动作改为双手同时向后划水的动作(和蝶泳划手一样),可以获得最大的冲     

Kinematic,kinetic and EMG analysis of four front crawl flip turn techniques

This study aimed to analyse the kinematic, kinetic and electromyographic characteristics of four front crawl flip turn technique variants. The variants distinguished from each other by differences in body position (i.e. dorsal, lateral, ventral) during rolling, wall support, pushing and gliding phases. Seventeen highly trained swimmers (17.9 ± 3.2 years old) participated in interventional sessions and performed three trials of each variant, being monitored with a 3-D video system, a force platform and an electromyography (EMG) system. Studied variables: rolling time and distance, wall support time, push-off time, peak force and horizontal impulse at wall support and push-off, centre of mass horizontal velocity at the end of the push-off, gliding time, centre of mass depth, distance, average and final velocity during gliding, total turn time and electrical activity of Gastrocnemius Medialis, Tibialis Anterior, Biceps Femoris and Vastus Lateralis muscles. Depending on the variant, total turn time ranged from 2.37 ± 0.32 to 2.43 ± 0.33 s, push-off force from 1.86 ± 0.33 to 1.92 ± 0.26 BW and centre of mass velocity during gliding from 1.78 ± 0.21 to 1.94 ± 0.22 m · s^?1. The variants were not distinguishable in terms of kinematical, kinetic and EMG parameters during the rolling, wall support, pushing and gliding phases.     

Kinematic analysis of butterfly turns of international and national swimmers

The aims of this study were (1) to evaluate the different turn phases of 200 m butterfly during competition in a 50 m pool, (2) to determine if wall contact times are related to swim speed and (3) to compare the turn variables of a European Champion with other swimmers. In the first part of the study, we assessed the turns of 22 swimmers ranked in three groups according to 200 m butterfly swim performance (fast group = 121.73 - 3.03 s, intermediate group = 126.25 - 0.55 s, slow group = 129.24 - 2.30 s). Two turn times were recorded: the first before the turn (i.e. the time it takes the swimmer's head to reach the wall from 7.5 m away) and the second after the turn (i.e. the time from the wall to the point at which the swimmer's head passes 7.5 m away). The third turn was performed significantly faster by the fast group than by the slow group, both before ( P ? 0.01) and after ( P ? 0.02) the turn. In the second part of the study, objectives (2) and (3) were evaluated among 15 swimmers based on a specific protocol. Three cameras (50 Hz) simultaneously recorded the turn; these were placed above the water 10 m before the wall, 5 m before and just above the wall. Longer contact times of the feet on the wall were associated with a faster push-off speed ( P ? 0.02). The European Champion achieved an improved contact time while performing a rapid pull-out speed.     

Kinematic analysis of butterfly turns of international and national swimmers

The aims of this study were (1) to evaluate the different turn phases of 200 m butterfly during competition in a 50 m pool, (2) to determine if wall contact times are related to swim speed and (3) to compare the turn variables of a European Champion with other swimmers. In the first part of the study, we assessed the turns of 22 swimmers ranked in three groups according to 200 m butterfly swim performance (fast group = 121.73+/-3.03 s, intermediate group = 126.25+/-0.55 s, slow group = 129.24+/-2.30 s). Two turn times were recorded: the first before the turn (i.e. the time it takes the swimmer's head to reach the wall from 7.5 m away) and the second after the turn (i.e. the time from the wall to the point at which the swimmer's head passes 7.5 m away). The third turn was performed significantly faster by the fast group than by the slow group, both before (P< 0.01) and after (P< 0.02) the turn. In the second part of the study, objectives (2) and (3) were evaluated among 15 swimmers based on a specific protocol. Three cameras (50 Hz) simultaneously recorded the turn; these were placed above the water 10 m before the wall, 5 m before and just above the wall. Longer contact times of the feet on the wall were associated with a faster push-off speed (P < 0. 02). The European Champion achieved an improved contact time while performing a rapid pull-out speed.     

The relationship between leg preference and knee mechanics during sidestepping in collegiate female footballers

This study examined the relationship between leg preference and knee mechanics in females during sidestepping. Three-dimensional data were recorded on 16 female collegiate footballers during a planned 45° sidestep manoeuvre with their preferred and non-preferred kicking leg. Knee kinematics and kinetics during initial contact, weight acceptance, peak push-off, and final push-off phases of sidestepping were analysed in both legs. The preferred leg showed trivial to small increases (ES = 0.19–0.36) in knee flexion angle at initial contact, weight acceptance, and peak push-off, and small increases (ES = 0.21–0.34) in peak power production and peak knee extension velocity. The non-preferred leg showed a trivial increase (ES = 0.10) in knee abduction angle during weight acceptance; small to moderate increases (ES = 0.22–0.64) in knee internal rotation angle at weight acceptance, peak push-off, and final push-off; a small increase (ES = 0.22) in knee abductor moment; and trivial increases (ES = 0.09–0.14) in peak power absorption and peak knee flexion velocity. The results of this study show that differences do exist between the preferred and non-preferred leg in females. The findings of this study will increase the knowledge base of anterior cruciate ligament injury in females and can aid in the design of more appropriate neuromuscular, plyometric, and strength training protocols for injury prevention.     

An analysis of the rollover backstroke turn by age-group swimmers

Kinetic (3-D force plate), kinematic (videography) and temporal characteristics of backstroke turns by 20 male and 16 female swimmers were recorded to identify and describe key elements of backstroke turning performance. Data were recorded during a 50 m maximum effort swim in a 25 metre pool. A Pearson product moment correlation matrix revealed that the 5 m RTT was significantly correlated with anthropometric measures of height, mass, trochanteric height and age; kinetic measures of horizontal impulse and peak force; and kinematic measures of wall contact time and peak velocity. The stepwise multiple regression equation to predict 5 m RTT was: 19.6-0.75 trochanteric height-1.8 wall exit velocity-0.03 peak vertical force. Four key factors were identified from a principle components factor analysis--anthropometry and force, post-turn velocity, force preparation and rotational skills. Implications from the findings were that age-group backstrokers should 'hit the wall hard' with relatively extended legs to reduce swim distance and push-off deceleration; use minimal wall contact time, and maximise forces to develop high horizontal velocities in a streamlined position.     

The validation of a swimming turn wall-contact-time measurement system: a touchpad application reliability study

The effectiveness of the swimming turn is highly influential to overall performance in competitive swimming. The push-off or wall contact, within the turn phase, is directly involved in determining the speed the swimmer leaves the wall. Therefore, it is paramount to develop reliable methods to measure the wall-contact-time during the turn phase for training and research purposes. The aim of this study was to determine the concurrent validity and reliability of the Pool Pad App to measure wall-contact-time during the freestyle and backstroke tumble turn. The wall-contact-times of nine elite and sub-elite participants were recorded during their regular training sessions. Concurrent validity statistics included the standardised typical error estimate, linear analysis and effect sizes while the intraclass correlating coefficient (ICC) was used for the reliability statistics. The standardised typical error estimate resulted in a moderate Cohen’s d effect size with an R² value of 0.80 and the ICC between the Pool Pad and 2D video footage was 0.89. Despite these measurement differences, the results from this concurrent validity and reliability analyses demonstrated that the Pool Pad is suitable for measuring wall-contact-time during the freestyle and backstroke tumble turn within a training environment.     

Lower limb joint kinetics and ankle joint stiffness in the sprint start push-off

Sprint push-off technique is fundamental to sprint performance and joint stiffness has been identified as a performance-related variable during dynamic movements. However, joint stiffness for the push-off and its relationship with performance (times and velocities) has not been reported. The aim of this study was to quantify and explain lower limb net joint moments and mechanical powers, and ankle stiffness during the first stance phase of the push-off. One elite sprinter performed 10 maximal sprint starts. An automatic motion analysis system (CODA, 200 Hz) with synchronized force plates (Kistler, 1000 Hz) collected kinematic profiles at the hip, knee, and ankle and ground reaction forces, providing input for inverse dynamics analyses. The lower-limb joints predominately extended and revealed a proximal-to-distal sequential pattern of maximal extensor angular velocity and positive power production. Pearson correlations revealed relationships (P < 0.05) between ankle stiffness (5.93 ± 0.75 N x m x deg(-1)) and selected performance variables. Relationships between negative power phase ankle stiffness and horizontal (r = -0.79) and vertical (r = 0.74) centre of mass velocities were opposite in direction to the positive power phase ankle stiffness (horizontal: r = 0.85; vertical: r = -0.54). Thus ankle stiffness may affect the goals of the sprint push-off in different ways, depending on the phase of stance considered.     

Imitation jumps in ski jumping: Technical execution and relationship to performance level

ABSTRACT

Imitation jumps are frequently used in training for ski jumping. Yet, the dynamics of these jumps differ considerably. Thus, the relevance of imitation jumps for ski jumping performance is not elucidated. The aim of this study was to investigate the relationship between the technical execution of imitation jumps and ski jumping performance level. We compared the imitation jumps of 11 ski jumpers of different performance levels using a Spearman correlation transform of time traces of the kinetics (measured using force cells and motion capture) of imitation jumps. The kinetic aspects that were related to performance centred on the moment arm of ground reaction force to the centre of mass before the onset of the push-off, angular momentum early in push-off, thigh angle during the main period of push-off and vertical velocity towards the end of push-off. We propose that the thigh angle may be a key element allowing high development of linear momentum while preparing for appropriate aerodynamic position. Furthermore, the findings suggest that the kinetic development prior to (and during) push-off is more important than the kinematic end state at take-off.     

Ice hockey skate starts: a comparison of high and low calibre skaters

The forward skating start is a fundamental skill for ice hockey players, yet extremely challenging given the low traction of the ice surface. The technique for maximum skating acceleration of the body is not well understood. The aim of this study was to evaluate kinematic ice hockey skating start movement technique in relation to a skater’s skill level. A 10-camera motion capture system placed on the ice surface recorded “hybrid-V” skate start movement patterns of high and low calibre male ice hockey players (n = 7, 8, respectively). Participants’ lower body kinematics and estimated body centre of mass (CoM) movement during the first four steps were calculated. Both skate groups had similar lower body strength profiles, yet high calibre skaters achieved greater velocity; skating technique differences most likely explained the performance differences between the groups. Unlike over ground sprint start technique, skating starts showed greater concurrent hip abduction, external rotation and extension, presumably for ideal blade-to-ice push-off orientation for propulsion. Initial analysis revealed similar hip, knee and ankle joint gross movement patterns across skaters, however, further scrutiny of the data revealed that high calibre skaters achieved greater vertical CoM acceleration during each step that in turn allowed greater horizontal traction, forward propulsion, lower double-support times and, accordingly, faster starts with higher stride rates.