The penalty throw in water polo: a cinematographic analysis

Three-dimensional (3-D) high-speed cinematography was used to record the penalty throw in water polo by six elite male (M) and six elite female (F) players. The direct linear transformation technique (DLT) was used in the 3-D space reconstruction from 2-D images recorded via laterally placed phase-locked cameras operating at 200 Hz. Five of the twelve subjects lifted the ball from underneath at the start of the throw whilst the remaining subjects opted for a rotation lift. As the ball was brought behind the head the females used very little hip and shoulder rotation compared to the male players so that four of the six female subjects were square on to the target at the rear point. At the completion of the backswing the wrist was flexed to a similar angle (M-162 degrees; F-158 degrees); the elbow angle showed significantly greater flexion for females (85 degrees) than males (107 degrees). During the forward swing, from rear point to release, the wrist joint of the female players flexed from a rear point angle of 158 degrees to 148 degrees at release. The wrist movement for male subjects was different from the females in that it flexed from 162 degrees to 147 degrees, 0.10 s prior to release and then extended to 159 degrees at palmar release before again flexing to 156 degrees at release. The amount of elbow extension during the forward swing was 48 degrees for both groups; however, the females actually released the ball with the forearm vertical (89 degrees) compared to the male forearm angle of 78 degrees. Maximum angular velocity of the wrist and elbow occurred at release for 9 of the 12 subjects. Both the wrist and elbow joints (F-148 degrees; M-156 degrees at wrist and F-126 degrees; M-148 degrees at elbow) demonstrated greater flexion at release in female subjects, compared with males. Maximum linear endpoint velocities for the forearm and hand segments occurred at ball release resulting in mean ball velocities of 19.1 m s-1 and 14.7 m s-1 for male and female subjects respectively.     

对水球中锋训练的探讨

中锋在水球比赛中的重要作用及加强中锋训练的几点措施和方法．     

优秀水球运动员膝关节肌群等速向心收缩力量特征研究

利用等速测试及康复系统对优秀水球运动员膝关节肌群进行等速向心收缩测试与分析,结果发现,峰力矩可作为评价水球运动员膝关节肌力大小的一个敏感指标,峰力矩值越大,肌肉做功能力越强,做功效率越高。水球运动员膝关节慢速肌力与快速肌力呈非常显著相关,其左右膝关节肌力相当平衡,快速屈伸肌比率大于慢速屈伸肌,屈肌的慢速力量较弱。     

The effects of fatigue on decision making and shooting skill performance in water polo players

Abstract

The aim of this study was to assess the effects of fatigue on decision making and goal shooting skill in water polo. Fourteen junior elite male players (age 17.2 ± 0.5 years; mass 84.2 ± 7.6 kg; height 1.85 ± 0.05 m) completed four sets of eight repetitions of an approximately 18 s maximal water polo specific drill. Progressively declining rest ratios for each successive set of the drill were employed to induce increasing fatigue and reflect the demands of match-play. A video-based temporally occluded decision-making task (verbalized response to various tactical situations) or goal shooting skill test (qualitative and quantitative analysis of goal shooting) was performed after each set. Heart rate, rating of perceived exertion (RPE) and blood lactate concentration were recorded. Heart rate (159 ± 12, 168 ± 13, 176 ± 12, 181 ± 12 Deats min^?1; P < 0.001) and RPE (13.1 ± 2.2, 15.5 ± 1.7, 17.3 ± 1.6, 19.1 ± 1.1; P < 0.001) increased with declining rest ratios. At very high fatigue, decision-making accuracy was 18.0 ± 21.8% better than at low fatigue (P = 0.008). Shooting accuracy and velocity were unaffected by incremental fatigue; however, skill proficiency (technique) decreased by 43 ± 24% between the pre-test and high-fatigue conditions (P < 0.001). In conclusion, incremental increases in fatigue differentially influenced decision making (improved) relative to the technical performance (declined), accuracy and speed of the ball (unchanged) of a water polo goal shot.     

Differences in trunk and upper extremity kinematics and segmental velocities during the offside forehand polo swing between male and female athletes

ABSTRACT

Although polo is a well-known equestrian sport, it is fundamentally misunderstood. The purpose of this study was to examine trunk and upper extremity kinematics and segmental velocities during the offside forehand polo swing between male and female athletes. Ten female and 17 male professional polo athletes volunteered. An electromagnetic tracking system collected kinematic data at 100 Hz while participants performed three offside forehand polo swings from a stationary wooden horse. One-way ANOVAs revealed statistically significant differences (p<0.05) in all kinematic variables and segmental velocities. Specifically, males exhibited a greater mean difference (MD=23°) of trunk flexion at take away (TA) and top of backswing (TOB)(MD=29°) trunk lateral flexion at ball contact (BC)(MD=23°), trunk rotation at TA(MD=97°) and TOB(MD=118°), shoulder abduction at TOB(MD=64°), and shoulder elevation at TOB(MD=13°) and BC(MD=40°). Females displayed greater trunk rotation at BC(MD=91°), shoulder elevation at TA(MD=19°), and elbow flexion at TA(MD=90°). Additionally, females generated greater segmental velocities early in the swing, while the males generated velocity later. The movement patterns observed amongst the males suggest energy is being transferred more efficiently along the kinetic chain, thus more efficient swing mechanics, but further investigation into the role of the trunk and lumbopelvic-hip complex in reference to the polo swing is warranted.     

The influence of game duration and playing position on intensity of exercise during match-play in elite water polo players

Abstract

In this study, we assessed exercise intensity in 20 water polo games of different duration. The hypothesis that right wing players perform at a higher intensity than back and forward central players was also tested. Thirty water polo players, equally split between three field positions, participated in the study. Initially, their performance-related physiological capabilities were evaluated. Subsequently, during water polo games of short (4×7-min periods) or long duration (4×9-min periods), heart rate was monitored continuously and blood lactate concentration was measured at the end of each period. Activity patterns were also recorded using a video camera. Mean heart rate over the entire game was 156 ± 18 beats · min^?1. Overall exercise intensity fluctuated around a value corresponding to the lactate threshold (4.03 ± 0.96 mmol · l^?1, 86 ± 5% of peak heart rate) and decreased (P < 0.003) with game time (4.22 ± 1.8 and 3.47 ± 1.9 mmol · l^?1 in the second and fourth quarter, respectively). During the last 6 min, heart rate was higher (P < 0.001) in games of short duration (156 ± 3 beats · min^?1) than in games of long duration (152 ± 8 beats · min^?1). Video analysis showed that the percentage of time spent in low-intensity activities (i.e. “out of game”) was lower (23 vs. 26%), whereas that in high-intensity activities (i.e. “sprinting crawl”) was higher (21 vs. 19%), in games of short compared with long duration. No difference was observed among players of various field positions in any of the variables examined. Thus during match-play, games of long duration produced significantly lower heart rate responses than games of short duration, and the physiological response exhibited by the players was not affected by field position. The water polo authorities should consider these results before changing game duration and coaches should prepare their athletes accordingly.     

马球文化:唐文化的潜流

唐代曾经是我国历史上最为辉煌的一个时期。盛唐气象已成为后人对唐文化最普遍和最具代表性的认识。唐文化的发展和影响在中国历史上是空前的。唐代城市的繁荣,经济的发达,文化的昌盛,大大促进了体育文化的发展,唐文化的精神实质也深深地烙入了体育文化之中。马球是唐代最流行的一项运动,它似一股隐藏的潜流,彰显着这个时代的文化和社会生活。     

Effects of competition level on the centre forward role of men's water polo

Abstract

This study aimed to compare specific technical and tactical indicators of the team and centre forward role of Euro League, and Italian Serie A1, Serie A2, and Serie B men's water polo club competitions. A notational analysis was performed on 21 water polo matches to evaluate the occurrence of technical and tactical team and centre forward indicators, highlighting differences among championships according to chi-square analyses. Differences emerged for Counterattack (P < 0.001) and Power-Play (P < 0.001) possessions, Even (P < 0.001; Euro League: 3 ± 1, Serie A1: 3 ± 2, Serie A2: 3 ± 2, Serie B: 6 ± 4) and Power-Play (P = 0.001) goals, and exclusions and penalties (P = 0.008) of the team during Even possessions. Relatively to the role analyses, effects emerged for perimeter players playing events (P = 0.049), as well as for centre forwards' goals (P = 0.007) and exclusions and penalties (P < 0.001; Euro League: 8 ± 1, Serie A1: 6 ± 2, Serie A2: 6 ± 2, Serie B: 3 ± 2) occurring at the end of Even possessions. Therefore, in Euro League, and Italian Serie A1 and Serie A2, teams perform a high occurrence of Power-Play possessions following up an exclusion, especially achieved by the centre forward during Even possessions, while, in Italian Serie B, goals were mostly scored during Even possessions, with a relevant contribution from the centre forward role.     

汉代马球小考

对汉代马球的存在和流行进行了梳理,同时借助江苏睢宁(淮陵)出土的东汉墓葬砖画中的打马球图形进行了分析,弥补了有关曹植《名都篇》和蔡孚《打球篇》所论述的东汉马球流行而没有文物佐证的缺陷,进一步证实了东汉时期马球已在中原地区流行。     

北京奥运会女子水球竞技特征分析

采用文献资料调研、数理统计、比较分析、录像观察统计等方法,对北京奥运会女子水球参赛的8支队伍及20场比赛进行全面的统计分析,从宏观与微观角度对各队的竞技特征进行剖析,深入研究现代女子水球竞技特征的发展趋势。结果表明,影响现代水球成绩的因素很多,如运动员的年龄结构及体态特征,运动员的综合素质及意识,各种技、战术的合理运用,进攻和防守的均衡发展等。强队体现出的最大特点就是进攻和防守的均衡化特征,超强的进攻并不能弥补防守弱带来的负面效应,俄罗斯队的失利,中国队强有力的进攻却止步四强,说明防守的优劣对比赛结果有重要影响。     

Overhead throwing in cricketers: A biomechanical description and playing level considerations

ABSTRACT

This study aimed to describe stationary overhead throwing biomechanics in South African cricketers, considering playing level, and relative to baseball. Kinematics and ground reaction forces were collected during throwing trials. Inverse dynamics was used to calculate joint kinetics. Inter-subject variability was calculated using the coefficient of variance. A one-dimensional statistical parametric mapping ANOVA was conducted to assess differences between the kinematic waveforms in elite and amateur cricketers (p < 0.05). Fifteen cricketers (elite = 8; amateur = 7) participated in this study. The basic parameters of a cricketer’s throwing action are described. Substantial inter-subject variability was noted for all variables, except lumbopelvic movement. Cricketers presented with 74.9 ± 27.3° glenohumeral external rotation and 94.8 ± 23.7° elbow flexion, at maximum external rotation (MER). Amateur cricketers displayed decreased elbow flexion range of motion between 2-14% of the throwing cycle (F = 9.365;p = 0.01); greater shoulder (121.0vs85.9 N; F = 0.36,p = 0.021) and elbow compression (105.6vs72.8 N;F = 0.007,p = 0.043), and superior shoulder force (203.1vs115.5 N;F = 2.43,p = 0.022) at MER, when compared with elite cricketers. Cricketers display similarities to baseball pitchers when throwing overhead from a stationary position. The “preparatory arc” utilised is different to the wind-up noted for baseball. The forces exerted on the shoulder and elbow, in amateur cricketers specifically, are substantially greater at MER and may indicate the potential risk for injury.     

马球运动起源于波斯考

马球运动源起何方,世人有多种说法.研究结果表明,这项运动起源于古代波斯,远在公元前6世纪就有文献记载,迄今已有2 600余年.波斯马球是怎样进入中国的?据文献分析,是唐朝初年由唐太宗李世纪亲自决策并组织引进的;由于唐朝同波斯的友好关系,马球活动是直接由波斯人那里传入的.马球传入中国的路径,有几种说法,都认为不是直接从波斯,而是经过若干中转才进入唐代的长安,这些说法都有严重缺失.     

吴健铁饼投掷技术的运动学分析

采用两台JVC9800高速摄像机以200fps的速度同步拍摄优秀青少年男子铁饼运动员吴健的铁饼投掷技术,并采用SIMI-motion录像解析系统进行图象解析.分析与诊断他的投掷技术并与优秀运动员进行比较研究,对加强我国男子铁饼后备人才队伍的建设和提高我国铁饼的整体水平具有重要意义.     

The effects of localised fatigue on upper extremity jump shot kinematics and kinetics in team handball

Team handball is a popular sport worldwide that requires numerous throws to be made throughout the course of a game. Because of the upper extremity demands of repetitive throwing, it is possible that fatigue can alter the mechanics of a shot. The purpose of this study was to determine the influence of localised fatigue on jump shot kinematics and kinetics. Eleven male team handball players (23.1 ± 3.1 years; 185.1 ± 8.3 cm; 89.7 ± 12.2 kg) volunteered. An electromagnetic tracking system was used to examine the jump shot prior to and following localised fatigue. The fatiguing protocol consisted of throwing a 2.2 kg medicine ball into a rebounder until volitional fatigue. No significant kinematic or kinetic differences were observed following fatigue. Shoulder external rotation was ?74.8 ± 14.9° prior to and ?79.0 ± 14.7° following fatigue at MER. Scapula, external rotation at ball release (BR) prior to fatigue was ?2.2 ± 7.0° and ?3.2 ± 11.1° following fatigue. Scapular internal rotation, at maximum shoulder internal rotation (MIR), changed from 18.4 ± 11.2° to 20.4 ± 11.8°. Ball velocity decreased from19.8 m · s^–1 to 18.8 m · s^–1 (P = 0.12). Accuracy percentage in the pre-fatigue trials was 60.8 ± 14.1% and 52.8 ± 12.7% following fatigue (P = 0.20). While no significant changes were observed, it is possible that other fatiguing protocols that more closely represent the aerobic and throwing demands of the sport may have a greater effect on the kinematics and kinetics of the jump shot.     

浅谈水球运动训练强度与量的结合

水球运动训练臻于成熟,然而新问题仍不断涌现,如今又出现了一个新的焦点:运动负荷最大化与合理化的平衡。运动负荷并不单指运动强度,而包括每个人所能承受的最大负荷。除此之外,还包括运动负荷的合理化因素。     

Throwing performance in water polo is related to in-water shoulder proprioception

ABSTRACT

Water polo players require a high level of upper-extremity strength, flexibility and coordination to achieve a peak level of throwing performance. Increased levels of shoulder proprioceptive acuity, strength and range of motion (ROM) have been previously associated with higher sporting performance. A coach-rating scale, used to quantify an athlete’s kicking proficiency in soccer; was adapted in the current study to measure each coach’s subjective expert opinion regarding athletes’ throwing mechanics, velocity, and accuracy. To examine this hypothesis shoulder proprioception acuity of 18 water polo players was measured both in-water and on-land using an AMEDA apparatus and correlated with coach-rated throwing performance and clinical measures of shoulder strength and ROM. There was a moderate positive correlation between the in-water and the on-land proprioception acuity (r = 0.47, p < 0.05). The in-water score showing a strong positive correlation with coach rated throwing mechanics (r = 0.68, p < 0.05) and velocity (r = 0.75, p = 0.02), suggesting that superior proprioception acuity contributed to fast, mechanically-efficient throwing. These findings support the notion that in-water proprioceptive acuity is an important determinant of the throwing performance achieved by water polo athletes and its measurement may be a valuable adjunct to current athlete screening.     

投掷项目最后用力顺序探讨

通过对投掷项目最后用力阶段存在问题的分类认识,以及对最后用力阶段运动学特征、解剖学特点、运动环节间力量传递基本原理的深入分析,认为:对投掷最后用力顺序的认识,属于特定阶段用力顺序的认识,对其认识不能脱离该阶段技术自身的本质特征;投掷最后用力顺序是右侧腿的踝、膝、髋肌肉依次发力;用力顺序与力的传导顺序是一致的。     

Comparison of pitching kinematics between youth and adult baseball pitchers: a meta-analytic approach

Coaches teach proper mechanics at a young age in an effort to increase pitching efficiency (i.e., proper pitching mechanics). Unfortunately, the mechanics taught to beginning pitchers are based on the findings from adult pitchers and may result in techniques that are detrimental to younger pitchers. The purpose of this study was to compare kinematics published for pitchers across various ages in an effort to determine whether the pitching techniques vary across developmental periods. A meta-analysis of papers published describing pitching kinematics for youth and adult pitchers was conducted. Maximal rotational velocity of the trunk and maximum external rotation of the shoulder were observed during the arm cocking phase. Peak magnitudes for abduction, horizontal adduction, and shoulder internal rotation were observed during the deceleration phase of the movement. In addition, by comparing previously published data across youth and adult pitchers, valuable insight into the differences in mechanics was gained. The results demonstrated that there are some distinct differences between youth and adult pitching mechanics. This finding may allow increased focus to be applied to those parameters observed to differ across age, increasing the knowledge base available for coaches to properly instruct youth pitchers.     

我国优秀女子水球运动员身体成分及身体机能特征研究

目的：研究我国优秀女子水球运动员身体成分与身体机能特点,为水球运动的发展提供研究和实践参考。方法：采用BODPOD空气置换法,对自我国5支省代表队的55名优秀女子水球运动员进行体成分与身体机能测试,并按照运动等级的不同进行统计分析。结果：55名运动员的体脂百分比（％）为24．02±4．86;健将级运动员比一级运动员的体重、握力与台阶指数都明显较大,差异具显著性（p〈0．05）,其它机能指标不具显著差异;我国优秀女子水球运动员的体脂百分比我国优秀女子游泳运动员高。结论：本研究提供了一些反映女子水球运动体质要求特点的测试数据;发现女子水球运动员有较高的体脂含量,应控制身体脂肪含量;健将级运动员比一级运动员体重更大,有更强的心肺功能与上肢力量。     

中国男子水球队竞技现状分析

采用现场统计、数理统计、逻辑分析等方法,从运动员的年龄,及外线射门、中锋射门、防守反击、六打五攻防等技战术应用效果,分析全国男子水球冠军赛中各队伍的竞技能力的基本特征。结果显示：我国各男子水球队发展不平衡,各队整体实力差异明显,且各队的整体厚度不够,除广东队和上海队外,其余各队缺乏核心队员和技战术特色风格等;队员在技战术上不够细腻,控制比赛节奏能力还需进一步提高。中国男子水球队要整体发展提高,还需遵循水球运动的发展规律,加强人才培养及技战术训练实践和训练理念的改变,重视训练的科学化,积极探索水球运动的制胜因素,确立正确的指导思想。