Fine body movements and the cardiac cycle in archery

This study examined the relationships between postural sway, aiming time, the cardiac cycle time and the placement of the first finger movement within the electrocardiac cycle, with the quality of the arrow shot. A small group of elite male and female archers who shot either the recurve or the compound bow, freestyle or bare bow was used in this study. A total of 240 arrows were shot, classified as being of good, average or bad quality and analysed in detail. The analyses were undertaken over two occasions up to 100 days apart. The area of postural sway, as measured by the movement of the centre of pressure coordinates, varied significantly (P less than 0.05-0.001) both within and between trials for all archers and for all quality of arrows shot. There was a tendency for the area of postural sway to increase as the quality of the arrow shot decreased. This increase in postural sway exceeded, for arrows of bad quality, that exhibited as normal postural sway when standing relaxed and addressing the target with the hands at the side. Aiming time was variable within the quality of arrow shot, although it was consistent for each archer. In some cases the aiming time increased as the quality of the arrow decreased, whereas in the case of bare bow archery the aiming time tended to decrease as the quality of the arrow deteriorated. The cardiac cycle time increased significantly (P less than 0.05-0.01) as the archers approached the loose of the good quality arrows but there was no significant increase in cardiac cycle time when arrows of average or bad quality were shot. The most consistent parameter related to the quality of the shot was the placement of the first finger movement within the ST phase or the mid-cycle phase of the electrocardiogram for arrows of good quality (P less than 0.0001).     

Postural consistency in skilled archers

The consistency of an archer's postural set at the moment of loose (arrow release) is commonly perceived to be an important determinant of success. The coach seeks, among other things, to provide the archer with information about postural consistency, details of which he acquires by eye or occasionally by video-recordings. The gains that might be achieved from more precise information are examined here. Nine skilled archers, classified into either skilled or elite groups according to their officially computed handicap, were continuously monitored and measured with a three-dimensional co-ordinate analyser (Charnwood Dynamics Coda-3 Scanner) while shooting two ends (series) of three arrows each. Considerable variability was observed in the precision with which the positions of head, elbow and bow at the moment of loose were replicated by archers of similar levels of skill. These results are interpreted to suggest that precise postural consistency may not be the primary feature distinguishing between the performance of archers at the higher skill levels.     

Electromyographic analysis of bow string release in highly skilled archers

A predominant archery coaching tenet holds that the most effective means of releasing the bow string is by relaxation of the finger flexor muscles without activation of finger extensors. To evaluate the validity of this view, EMG patterns of the flexor digitorum superficialis and extensor digitorum muscles of the draw arm were examined using surface EMG electrodes in 15 highly skilled archers as each performed six shots. Each archer displayed consistent EMG patterns from shot-to-shot and two distinct flexor-extensor patterns were exhibited by the sample. The first, characterized by eight of the archers, supported the relaxation principle. For these archers, both flexor and extensor digitorum activity decreased markedly immediately prior to or at arrow release. The second pattern, characteristic of the remaining seven archers, contradicted the coaching tenet. While the flexor digitorum pattern was essentially the same as that described for the first pattern, the extensor digitorum displayed a marked increase in activity just prior to release, indicating that string release was facilitated by an active extension of the fingers. It was concluded that highly skilled archers do not predominantly reflect a release consistent with the coaching canon and that factors other than the string release mechanism discriminate the performances of skilled archers.     

Postural stability,clicker reaction time and bow draw force predict performance in elite recurve archery

Recurve archery is an Olympic sport that requires extreme precision, upper body strength and endurance. The purpose of this research was to quantify how postural stability variables both pre- and post-arrow release, draw force, flight time, arrow length and clicker reaction time, collectively, impacted on the performance or scoring outcomes in elite recurve archery athletes. Thirty-nine elite-level recurve archers (23 male and 16 female; mean age?=?24.7?±?7.3 years) from four different countries volunteered to participate in this study prior to competing at a World Cup event. An AMTI force platform (1000Hz) was used to obtain centre of pressure (COP) measurements 1s prior to arrow release and 0.5s post-arrow release. High-speed footage (200Hz) allowed for calculation of arrow flight time and score. Results identified clicker reaction time, draw force and maximum sway speed as the variables that best predicted shot performance. Specifically, reduced clicker reaction time, greater bow draw force and reduced postural sway speed post-arrow release were predictors of higher scoring shots. It is suggested that future research should focus on investigating shoulder muscle tremors at full draw in relation to clicker reaction time, and the effect of upper body strength interventions (specifically targeting the musculature around the shoulder girdle) on performance in recurve archers.     

控球次数、控球质量和命中率对水球决赛胜负的影响

以第14届世界游泳锦标赛水球决赛为研究对象,运用相关分析方法,从常规赛、加时赛、全场比赛3个不同的时间角度,分析控球次数、控球质量、命中率3个因素对这场比赛得分的影响。研究表明：控球次数、控球质量对塞尔维亚队的常规赛、加时赛、全场比赛得分没有影响,命中率对塞尔堆亚队的常规赛、加时赛、全场比赛得分有重要影响;控球次数、控球质量对意大利队的常规赛、全场比赛得分没有影响,但对悫大利队加时赛得得分有非常重要影响,命中率对意大利队的常规赛、加时赛、全场比赛得分有重要影响。建议在我啊水球训练中,强调命中率的重要性,并加强射门训练环节,以提高在比赛当中的命中率。从而争取更多的胜利。     

基于目标向量函数模型的射箭训练监控案例研究

研究目的:定量研究特定运动员某阶段射箭训练中各影响因素对中靶情况的作用,为改进训练提供依据。方法:用自行设计的射箭运动训练多参数实时同步检测系统对训练中的瞬时心率曲线、弓片应变、撒放时间、动作视频、靶视频、箭初速等参数进行实时同步检测,在非线性时变目标向量函数模型的一阶简化基础上,估算各影响因素的扰动量。结论:对两名运动员实测分析表明,撒放时间、心率等因素对不同运动员中靶的影响不同,为运动员个性化训练提供了参考方向。     

Autonomic nervous system modulation during an archery competition in novice and experienced adolescent archers

Abstract

We assessed autonomic nervous system modulation through changes in heart rate variability during an archery competition as well as archery performance by comparing novice and experienced adolescent archers. Seven novice (age 14.0 ± 8.5 years, body mass index 22.9 ± 4.3 kg · m^?2, training experience 0.4 ± 0.3 years) and ten experienced archers (age 16.5 ± 10.3 years, body mass index 22.4 ± 3.1 kg · m^?2, training experience 4.1 ± 0.9 years) volunteered. Using beat-by-beat heart rate monitoring, heart rate variability was measured for 20 s before each arrow shot during two rounds of competition. We found that, compared with novices, experienced adolescent archers: (i) take more time per shot; (ii) have a higher low frequency band, square root of the mean of squared differences between successive R-R intervals (i.e. the time elapsing between two consecutive R waves in the electrocardiogram), and percentage of successive normal-to-normal intervals greater than 50 ms; and (iii) demonstrate an increase in parasympathetic nervous system activity compared with pre-competition values. We propose that these characteristics of experienced archers are appropriate for optimal performance during competition.     

Autonomic nervous system modulation during an archery competition in novice and experienced adolescent archers

We assessed autonomic nervous system modulation through changes in heart rate variability during an archery competition as well as archery performance by comparing novice and experienced adolescent archers. Seven novice (age 14.0 ± 8.5 years, body mass index 22.9 ± 4.3 kg · m(-2), training experience 0.4 ± 0.3 years) and ten experienced archers (age 16.5 ± 10.3 years, body mass index 22.4 ± 3.1 kg · m(-2), training experience 4.1 ± 0.9 years) volunteered. Using beat-by-beat heart rate monitoring, heart rate variability was measured for 20 s before each arrow shot during two rounds of competition. We found that, compared with novices, experienced adolescent archers: (i) take more time per shot; (ii) have a higher low frequency band, square root of the mean of squared differences between successive R-R intervals (i.e. the time elapsing between two consecutive R waves in the electrocardiogram), and percentage of successive normal-to-normal intervals greater than 50 ms; and (iii) demonstrate an increase in parasympathetic nervous system activity compared with pre-competition values. We propose that these characteristics of experienced archers are appropriate for optimal performance during competition.     

射箭动作技术激光测试研究

通过改进激光测试仪,将激光测试技术应用于射箭技术动作分析,建立激光测试规范程式,将射箭运动员瞄准过程记录下来进行数据分析,建立射箭动作技术指标评价体系。对国家射箭队5名运动员进行激光测试,分析激光测试数据,总结其动作技术特点,用以指导射箭运动员的训练。研究发现,5位运动员的技术特点是稳定性非常好,动作比较规范、流畅,一致性好,风格属快节奏。     

国家优秀射箭运动员个人撒放箭时间的研究

采用肌电测试方法,研究我国优秀射箭运动员个人撒放箭时间。结果认为,我国优秀射箭运动员不论男、女,每个运动员相互之间存在很大差异;在动作技术已经比较成熟完善时,其撒放箭时间是否相对稳定对环数有一定影响。技术越稳定,撒放越果断,撒放箭时间越一致,在某一环数上的命中率就越高,成绩就越好。     

Aerodynamic properties of an archery arrow

Two support-interference-free measurements of aerodynamic forces exerted on an archery arrow (A/C/E; Easton Technical Products) are described. The first measurement is conducted in a wind tunnel with JAXA’s 60 cm Magnetic Suspension and Balance System, in which an arrow is suspended and balanced by magnetic force against gravity. The maximum wind velocity is 45 m/s, which is less than a typical velocity of an arrow (about 60 m/s) shot by an archer. The boundary layer of the arrow remains laminar in the measured Re number range (4.0 × 10³ < Re < 1.5 × 10⁴), and the drag coefficient is about 1.5 for Re > 1.0 × 10⁴. The second measurement is performed by a free flight experiment. Using two high-speed video cameras, we record the trajectory of an archery arrow and analyze its velocity decay rate, from which the drag coefficient is determined. In order to investigate Re number dependence of the drag coefficient in a wider range (9.0 × 10³ < Re < 2.4 × 10⁴), we have developed an arrow-shooting system using compressed air as a power source, which launches the A/C/E arrow at an arbitrary velocity up to 75 m/s. We attach two points (piles) of different type (streamlined and bullet) to the arrow-nose. The boundary layer is laminar for both points for Re less than about 1.2 × 10⁴. It becomes turbulent for Re larger than 1.2 × 10⁴ and the drag coefficient increases to about 2.6, when the bullet point is attached. In the same Re range, two values of drag coefficient are found for the streamlined point, of which the lower value is about 1.6 (laminar boundary layer) and the larger value is about 2.6 (turbulent boundary layer), confirming that the point-shape has a crucial influence on the laminar to turbulent transition of the boundary layer.     

Identification of temporal factors related to shot performance for indoor recurve archery

The purpose of this study was to investigate the temporal phases of the archery shot cycle that distinguish the arrows distance from centre, in an attempt to understand critical factors that affect performance. Fifteen archers of varying ability each performed 30 shots at 18 m. Fourteen potential predictor variables were measured for statistical modelling by stepwise multiple linear regression. The results show that pre-shot time (pre-performance routine), follow-through time (post-performance routine), aiming time, speed of the arrow and the %variation in clicker-release time, account for 7.7% of the variation in predicting shot performance. The results have implications for practice demonstrating factors that coaches should focus on to develop their athletes. Further work on pre-, but more importantly, post-performance routines are needed generally within sport research as they are lacking and have been shown to be important contributing factors in a number of sports.     

国家队射箭运动员动作技术的肌电特性

运用美国产Noraxon表面肌电遥测系统对国家射箭队男、女各12名运动员进行测试,分析结果表明:国家射箭队运动员在射箭动作的不同阶段尚存在部分不合理的肌肉用力特点;相对来说,无论是举弓时的肌肉激活顺序、主要肌肉用力特点,还是动作的一致性,均是女子运动员较男子运动员合理;以肌电RMS幅值的"标准差与平均数的比值"这个派生指标对运动员进行多支箭肌肉用力的一致性评价较合理。     

Inter-segmental coordination in progressions for the longswing on high bar

Abstract

The aim of this study was to determine if critical parameters for elite performance could be identified among a population of female shot putters. The performance of seven of the top women shot putters competing at the 2002 USA National Championships was examined. Video data were captured using two Panasonic 60 Hz cameras and the best throws of each athlete were digitized and analyzed using a Peak Motus three‐dimensional motion analysis system. Thirty variables were examined for their effect on the distance of the throw. Correlation analysis indicated that measured distance was positively correlated with release speed (r = 0.97, p < 0.0003) and shoulder‐hip separation (r = 0.72, p < 0.06) and negatively correlated with release angle (r = ‐0.74, p < 0.056), rear knee angle at rear foot touchdown (r = ‐0.93, p < 0.003) and rear knee angle at release (r = ‐0.76, p < 0.047). Greater knee flexion angle at both rear foot touch down and release along with a neutral shoulder‐hip angle at release were identified as the most critical parameters for success among this sample of elite women shot putters. The unique observation about the knee positions at specific events should assist in new training and coaching developments.     

Bow tuning in the vertical plane

Competition results in sport archery depend to a great extent upon the optimal combination of bow-arrow-archer system parameters. A significant part of bow tuning is vertical adjustment, the aim of which is to give an arrow zero angle of attack. It is conducted in a long and complicated manner and error correction takes a lot of time and effort. The goal of the research was to create an analytical method to determine an optimal combination of bow parameters, which ensures zero angle of attack for an arrow launched from a string. Mechanical and mathematical models of bow and arrow geometry in the vertical plane in braced and drawn situations were investigated. An asymmetrical scheme, rigid beams, concentrated elastic elements and elastic string were the main features of the model. Numerical results of a computer simulation are presented in tabular and graphical form, which makes it easy for sportsmen and coaches to use.     

Relationship between Perception of Pull and Draw in Archery

Abstract

Subjects (21 men and 28 women) were tested for maximal pull and comfortable pull, were assigned bows on the basis of comfortable pull, were retested for maximal and comfortable pull after 24 lessons. Although there was some relationship between bow weight and comfortable pull when data were analyzed on a coeducational basis, there was no such relationship when the analysis was on a single sex basis. There was also no adaptation of kinesthetic perception of a comfortable pull to the amount of pull in a comfortable draw.     

Experimental and theoretical research in archery

The aim of this study was to introduce certain methods and research techniques and to present the results of experiments on parameters of archery equipment to optimize the interaction of the archer-bow-arrow system's elements. In order to achieve the research requirements, the following were devised: 1. A mathematical model of an arrow's movement during its interaction with a bow. 2. A mechanical model of an archer-bow-arrow system, which constitutes a device for mechanical loosing of an arrow from the bow strings (DMLA). 3. Three series of high-speed filming. The mathematical model and computer simulation were used to describe the arrow's movement for various initial conditions and various parameters of the equipment, based on which a nomogram was constructed of the optimum arrow parameters for bows of various draw forces. The device for the mechanical loosing of arrows from a bow was used to study the influence of selected parameters of the archer-bow-arrow system on the accuracy of shots. The film analysis was used to verify the mathematical and mechanical models constructed.     

2019年沙滩排球世锦赛男子决赛得分技术分析

我国沙滩排球运动于1994年被正式列为比赛项目,在近几年的发展中取得了较大的进步,但是男子沙滩排球与世界强队还有较大差距,本研究通过文献资料法、录像分析法、梳理统计法等方法针对2019年沙滩排球世锦赛男子决赛德国和俄罗斯在比赛中每一次得分所用的技术,观看录像统计德国每次得分前的技术和俄罗斯每次得分前的技术,以此作为研究基础,试图寻找各国强队运用最多的得分技术,为我国沙滩排球提供借鉴,并提出建议,以期为我国男子沙滩排球的针对性训练和运动成绩进一步提高提供数据参考。