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1.
Sport scientists have devoted relatively little attention to soccer penalty kicks, despite their decisive role in important competitions such as the World Cup. Two possible kicker strategies have been described: ignoring the goalkeeper action (open loop) or trying to react to the goalkeeper action (closed loop). We used a paradigm simulating a penalty kick in the laboratory to investigate the dynamics of the closed-loop strategy in these controlled conditions. The probability of correctly responding to the simulated goalkeeper motion as a function of time available followed a logistic curve. Kickers on average reached perfect performance only if the goalkeeper committed him or herself to one side about 400 ms before ball contact and showed chance performance if the goalkeeper motion occurred less than 150 ms before ball contact. Interestingly, coincidence judgement?-?another aspect of the laboratory responses?-?appeared to be affected for a much longer time (>500 ms) than was needed to correctly determine laterality. The present study is meant as groundwork for experiments in more ecological conditions applicable to kickers and goalkeepers.  相似文献   

2.
In the present study, we tested the consequences of attention towards goalkeepers in association football penalty shootouts that have exclusively been derived from laboratory experiments. We conducted a retrospective analysis of all penalty shootouts during FIFA World Cups (1986–2010) and UEFA European Football Championships (1984–2012). We linked key variables of previous laboratory research to observable behaviour in the field that was coded by two independent coders. The following hypotheses were tested: first, attention towards goalkeepers results in more saves/better goalkeeper performance; second, goalkeepers can deliberately distract penalty takers by drawing attention towards themselves which results in less accurate penalty kicks/better goalkeeper performance. Results were in line with previous laboratory analyses as they showed that attention towards goalkeepers resulted in more saves/better goalkeeping performance. Further, if goalkeepers distracted penalty takers this also resulted in better goalkeeping performance. The applied implications of these findings are discussed for both goalkeepers and penalty takers in association football.  相似文献   

3.
The purpose of this paper was to establish postural cues in kicking that may be of use to goalkeepers. Eight male soccer players (age 20.5 +/- 1.1 yrs; height 1.78 +/- 0.053 m; mass 75.18 +/- 9.66 kg) performed three types of kick: a low side-foot kick to the left hand corner of the goal, a low side-foot kick straight ahead, and a low instep kick straight ahead. Kicks were recorded by an optoelectronic motion analysis system at 240 Hz. At kicking foot take-off (about 200 ms before ball contact) the variables which were significantly different and could act as cues were support foot progression angle, pelvis rotation, and kicking hip and ankle flexion. The support foot progression angle was considered to be the most valuable of these variables as its angle coincided with the direction of ball projection. The other variables were less clear in their interpretation and so less valuable for a goalkeeper to use for decision making. Cues appearing after support foot contact were thought unlikely to be of value to a goalkeeper in their decision making. These include kicking leg knee flexion angle, and support leg shank and thigh angles.  相似文献   

4.
Abstract

The keeper-independent strategy, in which a football penalty kicker selects a target location in advance and ignores the goalkeeper's actions during the run-up, has been suggested to be the preferable strategy for taking a penalty kick. The current in-field experiment investigated the question of whether the goalkeeper can indeed be ignored. Ten intermediate-level football players were instructed to adopt a goalkeeper-independent strategy and to perform penalty kicks directed at one of two targets located in the upper corners of the goal under three conditions: without a goalkeeper, in the presence of a goalkeeper (who tried to save the ball), and in the presence of a goalkeeper who was informed by the penalty kickers where they intended to direct the ball. The mere presence of a goalkeeper impaired shot accuracy. The shots were more centralised, that is, biased toward the goalkeeper. The effects were enhanced for the condition in which the penalty kicker knew the goalkeeper was knowledgeable about ball direction. The findings were consistent with the response activation model that holds that aiming at a target can be biased toward salient visual non-targets. The implications for adopting and practising goalkeeper-independent strategies are discussed.  相似文献   

5.
足球守门员在防守点球运动情境中眼动特征的研究   总被引：1，自引：0，他引：1  
采用美国应用科学实验室(ASL)生产的504型眼动仪,以10名专业足球守门员和10名大学生足球守门员为被试,以防守点球为运动情境片段,对专业守门员的眼动特征进行实验性研究,比较两组守门员的眼动实验结果,探讨守门员在防守点球时眼动特征对决策准确性的影响.实验结果表明:1)在防守点球情境中,专业守门员与大学生守门员的眼动特征存在明显差异;2)专业守门员采用了相对合理的视觉搜索策略,注视点集中,注视分配主次明显,注视轨迹简单、实用,信息实效性更强;3)罚球运动员的支撑脚、摆动腿、脚触球是决定射门方向的主要观察点.在防守时,重点注视这三个区域,结合临场经验做出分析判断,可有效提高防守点球成功率;4)运动水平和临场经验对准确做出防守决策至关重要,运动水平越高,临场经验越丰富,防守决策准确率越高.  相似文献   

6.
The purpose of this paper was to establish postural cues in kicking that may be of use to goalkeepers. Eight male soccer players (age 20.5 ± 1.1 yrs; height 1.78 ± 0.053 m; mass 75.18 ± 9.66 kg) performed three types of kick: a low side-foot kick to the left hand corner of the goal, a low side-foot kick straight ahead, and a low instep kick straight ahead. Kicks were recorded by an optoelectronic motion analysis system at 240 Hz. At kicking foot take-off (about 200 ms before ball contact) the variables which were significantly different and could act as cues were support foot progression angle, pelvis rotation, and kicking hip and ankle flexion. The support foot progression angle was considered to be the most valuable of these variables as its angle coincided with the direction of ball projection. The other variables were less clear in their interpretation and so less valuable for a goalkeeper to use for decision making. Cues appearing after support foot contact were thought unlikely to be of value to a goalkeeper in their decision making. These include kicking leg knee flexion angle, and support leg shank and thigh angles.  相似文献   

7.
Abstract

Achieving a high ball velocity is important during soccer shooting, as it gives the goalkeeper less time to react, thus improving a player's chance of scoring. This study aimed to identify important technical aspects of kicking linked to the generation of ball velocity using regression analyses. Maximal instep kicks were obtained from 22 academy-level soccer players using a 10-camera motion capture system sampling at 500 Hz. Three-dimensional kinematics of the lower extremity segments were obtained. Regression analysis was used to identify the kinematic parameters associated with the development of ball velocity. A single biomechanical parameter; knee extension velocity of the kicking limb at ball contact Adjusted R2 = 0.39, p ≤ 0.01 was obtained as a significant predictor of ball-velocity. This study suggests that sagittal plane knee extension velocity is the strongest contributor to ball velocity and potentially overall kicking performance. It is conceivable therefore that players may benefit from exposure to coaching and strength techniques geared towards the improvement of knee extension angular velocity as highlighted in this study.  相似文献   

8.
Abstract

In this paper we examined the influence of opposing players constraining the decision-making of an attacker during shooting performance in futsal. Performance during 10 competitive matches was recorded and examined from the moment a shot was taken until the ball was intercepted or entered the goal in sequences of play: ending in a goal, a goalkeeper's save, or an interception by the nearest defender. The variables under scrutiny in this study were (i) the distance of each player to the ball's trajectory, (ii) the time for the ball to arrive at that same point (i.e. the interception point), and (iii), the required movement velocity of the nearest defender and the goalkeeper to intercept the ball. Results showed that values of distance from a defender and goalkeeper to the interception points were significantly lower when they intercepted the ball. The time of ball arrival at the interception point of the defender was also lower when the ball was intercepted. The required velocities of the nearest outfield defender and the goalkeeper to intercept the ball were significantly lower during plays in which they intercepted the ball, than in plays in which the ball was not intercepted. Our results suggest that researchers and practitioners should consider simultaneously both space and time in analysis of interceptive actions in team sports. The required movement velocities of the opponents to intercept the ball are reliable spatial-temporal variables constraining decision-making during shooting performance in team sports like futsal.  相似文献   

9.
The goalkeeper’s difficulty in the soccer penalty kick originates from the extreme spatiotemporal constraints of the situation. The present review claims that the current understanding is biased toward attributing a goalkeeper’s success in saving a penalty kick to perceptual–cognitive skill. To investigate the goalkeeper’s skill, researchers have often adopted video tasks. In doing so, they studied perceptual skill in isolation from action. We use affordance-based control theory to propose an alternative understanding and research methodology. We argue that goalkeepers in the penalty kick situation should regulate their actions in ways that sustain the perception of stoppability. To capture this, we outline the building blocks for a required lateral velocity model, in which the goalkeepers’ required actions are scaled to their maximum capabilities. In doing so, we provide new directions for research.  相似文献   

10.
This field experiment investigated the relative merits of approaching the penalty kick with either a keeper-independent or keeper-dependent strategy. In the keeper-independent strategy, the shooter selects a target location in advance and disregards the goalkeeper's actions during the run-up. In the keeper-dependent strategy, the shooter makes a decision resting on the anticipation of the goalkeeper's movements during the run-up. Ten intermediate-level soccer players shot at one of two visually specified targets to the right and left side of the goal. In the keeper-independent strategy condition, participants were told that the visually specified target would not change. In the keeper-dependent strategy condition, participants were told that in half of the trials the visually specified target would change side at different times before ball contact, indicating that the direction of the kick needed to be altered. The results showed that penalty-taking performance was apt to be less than perfect in the keeper-dependent strategy condition. A decrease in the time available to alter kick direction resulted in a higher risk of not only an incorrect but also inaccurate shot placement. It is concluded that anticipating the goalkeeper's movements may degrade penalty kick performance, mainly due to insufficient time to modify the kicking action.  相似文献   

11.
Abstract

This field experiment investigated the relative merits of approaching the penalty kick with either a keeper-independent or keeper-dependent strategy. In the keeper-independent strategy, the shooter selects a target location in advance and disregards the goalkeeper's actions during the run-up. In the keeper-dependent strategy, the shooter makes a decision resting on the anticipation of the goalkeeper's movements during the run-up. Ten intermediate-level soccer players shot at one of two visually specified targets to the right and left side of the goal. In the keeper-independent strategy condition, participants were told that the visually specified target would not change. In the keeper-dependent strategy condition, participants were told that in half of the trials the visually specified target would change side at different times before ball contact, indicating that the direction of the kick needed to be altered. The results showed that penalty-taking performance was apt to be less than perfect in the keeper-dependent strategy condition. A decrease in the time available to alter kick direction resulted in a higher risk of not only an incorrect but also inaccurate shot placement. It is concluded that anticipating the goalkeeper's movements may degrade penalty kick performance, mainly due to insufficient time to modify the kicking action.  相似文献   

12.
Many sports associated with anterior cruciate ligament (ACL) injury require athletes attend to a ball during participation. We investigated effects of attending to a ball on lower extremity mechanics during a side-cut maneuver and if these effects are consistent for males and females. Sagittal and frontal plane hip and knee kinematics and joint moments were measured during side-cut maneuvers in 19 male and 19 female National Collegiate Athletic Association division III basketball players. Participants also experienced two side-cut conditions that required attention to a ball. Our results did not indicate that the effect of attention varies with gender. However, during side-cut conditions while attending to a ball, internal knee adductor moment was 20% greater (p = 0.03) and peak knee flexion angle was 4 degrees larger (p < 0.01). Females demonstrated 5 degrees less hip flexion (p = 0.046), 12 degrees less knee flexion (p < 0.01), and 4 degrees more knee abduction (p = 0.026) at initial contact during all side-cut conditions than males. Attention to a ball may affect lower extremity mechanics relevant to ACL injury. The validity of laboratory studies of lower extremity mechanics for sports that include attention to a ball may be increased if participants are required to attend to a ball during the task.  相似文献   

13.
Abstract

We quantify the nature and frequency of anticipation behaviours in professional tennis using video coding of incidents where the time delay between the opponent's stroke and the reaction of the player were recorded. We argue that anticipation is based on uncertain information and should lead in some situations to erroneous decisions. We identified the transition between reaction (with 100% accuracy in the selection of where the ball is played on the court) and anticipation (with less than 100% accuracy) as being 140–160 ms after ball contact. Anticipation behaviours occurred on between 6.14% and 13.42% of the coded situations. These anticipation behaviours appeared almost exclusively in ‘unfavourable’ situations, where the opponent had a significant tactical advantage, with the type of playing surface having only a limited effect. Moreover, the decrease in accuracy with shorter response times is not monotonic, with an increase in response accuracy being observed for times shorter than 120 ms before ball contact. We propose that very early anticipation behaviours occur when players use significant context-specific information before the opponent's stroke. When such information is not available, players produce anticipation behaviours that are closer to the moment of ball–racket contact using information that is more likely to be based on the opponent's preparation of the stroke. This study opens new directions for research focusing on the testing and training of anticipation in fast ball sports.  相似文献   

14.
点球攻守是当今足球比赛中决定胜负的重要因素之一。本文通过大量数据分析推导得出,守门员在防守点球时的最佳扑救(反应)时机,应该选择在看到主罚队员最后一步助跑支撑脚上步离开地面的一瞬间,这样可以获得最佳的提前量。  相似文献   

15.
目的:自主动作可以引起感知衰减已经得到前期研究证实,但该现象的时间进程尚不明确,机制也存在争议。研究通过2个实验对上述问题进行探索。方法:实验1共纳入被试12人,使用随机动点运动一致性判断任务,结合信号检测论,探索感知衰减现象的时间进程;实验2共纳入被试14人,采用主观报告法对预激活与抑制假说进行验证。结果:实验1中,将动作执行前后450 ms共900 ms以每150 ms划分为一段,动作执行前300 ms至执行后150 ms的3段时间内,被试的辨别力d’在自主动作效果与刺激对应关系一致条件下显著降低(P均<0.05);其余3段时间内,被试的辨别力d’在自主动作效果与刺激对应关系一致与不一致条件下差异不显著(P均>0.05)。实验2中,被试在刺激强度低的条件下,对与自主动作效果一致的刺激的主观强度报告显著高于不一致的刺激(P<0.05);在刺激强度为高的条件下,对自主动作效果对应一致或不一致的刺激评分无显著差异(P>0.05)。结论:自主动作引起的感知衰减在动作执行前就已经发生,动作执行前的150 ms与执行后的300 ms是重要的时间节点。自主动作可以在两个节点内引起感知衰减,在其他时间无法引起感知衰减。自主动作所引起的感知系统的预激活是感知衰减的成因。  相似文献   

16.
The time of occurrence and spatial location of the advance cues used to anticipate the direction and force of an opponent's stroke in squash were examined using a film task. This task, designed to simulate the normal perceptual display of the defensive player, consisted of two discrete parts, each containing 160 individual stroke sequences (trials). In the first part of the film task, the display was occluded at different time intervals throughout the development of the opponent's stroke and the 16 expert and 20 novice subjects had to predict both the direction (down‐wall or cross‐court) and force (drive or drop shot) of the opponent's stroke. In the second part of the film task, visibility to selected advance cues was occluded by placing opaque mats on the film surface. Across all of the film task conditions experts were superior to novices in predicting the event outcome from the information available, highlighting the important contribution anticipatory skills make to expert performance in this sport. Analysis of lateral (direction) error showed that the most critical time periods for extracting information about stroke direction are the periods between 160–80 ms prior to racket‐ball contact and the period of extended ball flight arising at least 80 ms after contact. Whereas both groups were attuned to this ball flight information, only the experts were capable of picking up information from the early part of the opponent's actions. This early information appeared to be provided by the opposing player's arm action. Similar time periods were found to be also important for the prediction of stroke depth, but in this case both experts and novices were similar in their cue dependence.  相似文献   

17.
The time of occurrence and spatial location of the advance cues used to anticipate the direction and force of an opponent's stroke in squash were examined using a film task. This task, designed to stimulate the normal perceptual display of the defensive player, consisted of two discrete parts, each containing 160 individual stroke sequences (trials). In the first part of the film task, the display was occluded at different time intervals throughout the development of the opponent's stroke and the 16 expert and 20 novice subjects had to predict both the direction (down-wall or cross-court) and force (drive or drop shot) of the opponent's stroke. In the second part of the film task, visibility to selected advance cues was occluded by placing opaque mats on the film surface. Across all of the film task conditions experts were superior to novices in predicting the event outcome from the information available, highlighting the important contribution anticipatory skills make to expert performance in this sport. Analysis of lateral (direction) error showed that the most critical time periods for extracting information about stroke direction are the periods between 160-80 ms prior to racket-ball contact and the period of extended ball flight arising at least 80 ms after contact. Whereas both groups were attuned to this ball flight information, only the experts were capable of picking up information from the early part of the opponent's actions. This early information appeared to be provided by the opposing player's arm action. Similar time periods were found to be also important for the prediction of stroke depth, but in this case both experts and novices were similar in their cue dependence.  相似文献   

18.
Many sports associated with anterior cruciate ligament (ACL) injury require athletes attend to a ball during participation. We investigated effects of attending to a ball on lower extremity mechanics during a side-cut maneuver and if these effects are consistent for males and females. Sagittal and frontal plane hip and knee kinematics and joint moments were measured during side-cut maneuvers in 19 male and 19 female National Collegiate Athletic Association division III basketball players. Participants also experienced two side-cut conditions that required attention to a ball. Our results did not indicate that the effect of attention varies with gender. However, during side-cut conditions while attending to a ball, internal knee adductor moment was 20% greater (p = 0.03) and peak knee flexion angle was 4° larger (p < 0.01). Females demonstrated 5° less hip flexion (p = 0.046), 12° less knee flexion (p < 0.01), and 4° more knee abduction (p = 0.026) at initial contact during all side-cut conditions than males. Attention to a ball may affect lower extremity mechanics relevant to ACL injury. The validity of laboratory studies of lower extremity mechanics for sports that include attention to a ball may be increased if participants are required to attend to a ball during the task.  相似文献   

19.
Abstract

The location and outcome of all free kicks taken directly at goal in the 2007 women's football World Cup were assessed to identify areas with the most goal-scoring potential and assist with tactical decisions and training design. Video of all free kicks taken directly at goal in the 32 games was captured and the location of the ball on the pitch was calculated from pitch markings and image pixel coordinates using a customized curve-fitting method. The outcome of each free kick was determined and for those that resulted in a goal or were saved, information on ball flight time and the placement of the ball relative to the goal was reported. All seven free kicks that resulted in a goal were taken from a central area within 7 m of the penalty circle, placed at the edge of the goal within approximately 1 m of the goalpost, and had an average flight time of 1.09 s, which was significantly faster than for those that were saved. All free kicks directed towards the bottom and centre of the goal resulted in straightforward saves for the goalkeeper. It is recommended that teams should consider a direct shot from free kicks awarded within 7 m of the penalty circle. For free kicks from wide areas and areas further from the goal, players should be aware of their individual ability and only take a shot when they perceive the probability of scoring a goal to be high. Otherwise, alternative attacking strategies should be considered to avoid an easy turnover of possession.  相似文献   

20.
ABSTRACT

When executed correctly, swing bowling has the potential to influence the outcome of a cricket match, yet little is known about the required bowling action and ball flight characteristics. This study aimed to describe the bowling action and initial ball flight characteristics as well as to identify variables that may be associated with increased swing in pathway and high-performance medium and fast pace bowlers. A 17-camera Vicon motion analysis system captured retro-reflective markers placed on the upper-body of participants and new cricket balls to quantify bowling action and initial ball flight kinematics. Bowlers delivered the ball with their forearm and hand angled in the direction of intended swing with an extended wrist flexing through the point of ball release. Bowlers who produced more swing had increased seam stability, possibly linked to a lower wrist and ball angular velocity. It is believed that swing increases with seam stability, however, optimal ranges may exist for seam azimuth angle, ball angular velocity and release speed. These findings may assist coaches to optimise the performance of bowlers, however, future research should use bowlers who play at higher levels to investigate swing bowling at greater speeds.  相似文献   

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