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1.
The effect of local kinematic changes on anticipation judgments   总被引:1,自引:0,他引:1  
Skilled tennis players rely on a more global than local perceptual strategy when anticipating an opponent’s shot direction in tennis (Williams, Huys, Cañal-Bruland, & Hagemann, 2009). Global perceptual strategy refers to the pick-up of dynamic information across different body areas rather than from a single source such as the arm or racket. We extend previous work by examining the spatiotemporal characteristics of visual information pick-up when anticipating shot direction in tennis. We perturbed information from various body locations by interchanging the dynamics of selected areas with those from strokes played to the opposite side of the court. In addition, we presented each manipulation under four different temporal occlusion conditions (from 240 ms prior to racket-ball contact) to examine the time course of information extraction. Skilled tennis players outperformed less skilled counterparts in predicting shot direction, even at early phases of the opponent’s motion. Moreover, skilled players showed significant decrements in performance when the arms and racket were perturbed, highlighting the relevance of distal information when anticipating opponents’ intentions.  相似文献   

2.
We used principal components analysis (PCA) to investigate variations in the dynamical structure of handball penalty shots as a factor of target location and phase of shot. Participants completed a total of 10 successful shots to each of four target locations in the handball goal. Three dimensional movement time series data were analyzed. Also, data were analyzed across three temporally distinct time windows in line with the evolving kinematic chain. Statistical analyses were undertaken to determine differences across target locations. There were no significant differences between dynamical structures as a factor of target or phase. Covariance between time evolutions as a factor of target reduced in line with the ranking of the component. When shots were analyzed as three distinct time windows, only the low time evolution covariances suggested differences between targets in any time window. Our findings show that the dynamical structure underpinning the handball penalty shot does not differ greatly across locations. However, the time evolution of principal components suggests there are some variations in dynamics which may differentiate shot direction.  相似文献   

3.
This study aimed to demonstrate that one of the main sources of information that tennis players use to anticipate their opponents' strokes is prior knowledge of the upcoming events likely to develop when the player has the opportunity to impose his or her playing intent. Seventeen experienced male players were faced with simulated on‐court situations with three different delivery conditions such that their tactical initiative was high, moderate or weak (reflecting the possibilities of controlling rallies). Each situation finished with a passing shot from the opponent that the participant had to intercept with a volley stroke in the absence of visual information (vision occluded before the opponent's stroke). Analysis of directional responses showed that the participants were more accurate if they were in firm control of the rallies (high level of tactical initiative). Forecasts were also found to be more accurate for down‐the‐line backhand shots. These findings increase our understanding of anticipation in tennis. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

4.
The effects of viewing mug shots on subsequent identification performance are as yet unclear. Two experiments used a live staged-crime paradigm to determine if interpolated eyewitness exposure to mug shots caused interference, unconscious transference, or commitment effects influencing subsequent lineup accuracy. Experiment 1 (N = 104) tested interference effects. Similar correct decision rates were obtained for the mug shot and no mug shot groups from both perpetrator-present and absent lineups. Experiment 2 (N = 132) tested for commitment and transference effects. Results showed that the commitment group made significantly more incorrect identifications than either the control or the transference group, which had similar false-identification rates. Commitment effects present a serious threat to identification accuracy from lineups following mug shot searches.  相似文献   

5.
Differing viewpoints concerning the specificity and generality of motor skill representations in memory were compared by contrasting versions of a skill having either extensive or minimal specific practice. In Experiments 1 and 2, skilled basketball players more accurately performed set shots at the foul line than would be predicted on the basis of the performance at the nearby locations, suggesting considerable specificity at this distance. This effect was replicated even when the lines on the court were obscured (in Experiment 2). However, the effect was absent when jump shots were executed in Experiment 3. The authors argue that massive levels of practice at 1 particular member of a class of actions produce specific effects that allow this skill to stand out from the other members of the class, giving it the status of an especial skill. Various theoretical views are proposed to account for the development of these skills.  相似文献   

6.
What information underwrites visual anticipation skill in dynamic sport situations? We examined this question on the premise that the optical information used for anticipation resides in the dynamic motion structures, or modes, that are inherent in the observed kinematic patterns. In Experiment 1, we analyzed whole-body movements involved in tennis shots to different directions and distances by means of principal component analysis. The shots differed in the few modes that captured most of the variance, especially as a function of shot direction. In Experiments 2 and 3, skilled and less skilled tennis players were asked to anticipate the direction of simulated shots on the basis of kinematic patterns in which only the constituent dynamic structures were manipulated. The results indicated that players predicted shot direction by picking up the information contained in multiple low-dimensional dynamic modes, suggesting that anticipation skill in tennis entails the extraction of this dynamic information from high-dimensional displays.  相似文献   

7.
This study aims at specifying some of the cognitive processes underlying decision-making in squash competition. More specifically, the study focuses on the strategy of the defending player (D) when chosing among three categories of preparation (total preparation for one particular event, partial preparation in favor of one event and absence of biased preparation). D is viewed as an information processing system (IPS) placed in a problem-solving situation, the problem being what decision to reach. The results obtained in a preceding investigation about the nature of the information processed by a player to anticipate and prepare for the opponent's shot in a real game setting, are used to determine a typical protocol of the behavior of D. The analysis of this protocol allows one to formally define (in Backus-Normal-Form) the problem space of D which is also D's internal representation of the task environment. From the problem space are derived (1) the problem behavior graph depicting the search of D through his problem space for a solution, and (2) the production system (a set of conditional statements, each expressing what to do under specific conditions) defining the logic of the search. The results of this first phase of the simulation study of a decision-making model of squash competition show that the cognitive strategy of D is based upon the use of a specific preformed algorithm. This algorithm could be stored in some long-term memory and activated by the current state of information in short-term memory. Finally, the proposed model also leads to the suggestion that the cognitive strategy of the performer may be influenced by a variety of factors such as the experience of the player, the time pressure, the expectancies, the performer's confidence in his predictions and the mistakes caused by incorrect predictions.  相似文献   

8.
This study examined the links between historical team results and individual players' subsequent performances in a high-pressure real-world sport situation. Videos were obtained from all soccer penalty shootouts held in two major international tournaments (World Cup and European Championships) between 1976 and 2006 (n=260 players/309 kicks), and we controlled for team ability and country. The results showed that players on teams with preceding losses performed worse and generally took their shots more quickly than players on teams with preceding wins. These differences were also found with players who took no personal part in the preceding games. In conclusion, the results support the existence of historical dependency effects for performance on important and dramatic high-pressure tasks and they are in part consistent with a view of choking under pressure as a function of threatened egotism and self-regulation failure.  相似文献   

9.
ObjectiveThe aim of this study was to examine the influence of a defender on the performance of a motor skill from an invasion sport.DesignHighly skilled basketball players performed different variations of basketball shots using a randomised test schedule.MethodParticipants completed a total of 30 test trials comprising 6 trials of 5 different shot types in both defended and undefended conditions.ResultsThe presence of a defender led to significant changes in several behavioral measures including faster shot execution times, longer jump times, and an increase in the amount of time that the ball spent in the air as it travelled to the basket after being released from the shooter's hand. These behavioral changes were accompanied by an overall decline in shooting accuracy of over 20%. Defended shots also tended to elicit greater amounts of movement variability which, when interpreted in conjunction with the other findings, suggests that participants were attempting to adapt their movements to accommodate for the changing demands of the performance environment. Comparisons across different shot types revealed that the influence of the defender was generally context and task dependent.ConclusionsThe results have important implications for representative task design, and highlight how the manipulation of key information sources can have a marked effect upon behavioral responses.  相似文献   

10.
We applied the matching equation to evaluate the allocation of two- and three-point shots by male and female college basketball players from a large Division 1 university. The matching law predicts that the proportion of shots taken from three-point range should match the proportional reinforcement rate produced by such shots. Thus, we compared the proportion of three-point shots taken relative to all shots to the proportion of three-point shots scored relative to all shots scored. However, the matching equation was adjusted to account for the greater reinforcer magnitude of the three-point basket (i.e., 1.5 times greater than the two-point basket reinforcer magnitude). For players with substantial playing time, results showed that the overall distribution of two- and three-point shots was predicted by the matching equation. Game-by-game shot distribution was variable, but the cumulative proportion of shots taken from three-point range as the season progressed was predicted almost perfectly on a player-by-player basis for both male and female basketball players.  相似文献   

11.
This study extended research on sport expertise concerning the development of cognitive and motor skills in singles tennis (McPherson, 1999). 12 adult male professional and novice tennis players were videotaped during singles competition. Opponents for matches were randomly selected within each group of participants. Two tennis experts utilized an observational scale to judge players' performance generated during competition for serves and shots following the serve, e.g.. return of serves, lobs. Each player was scored on three performance components: quality of movement to or control of the ball for serves or shots attempted (control skills), appropriateness of serve or shot selections in the context of game situations (response selection skills), and quality of serves or shots produced (response execution skills). Relative frequency scores for the highest category of each performance component were derived according to the number of opportunities to respond. Serve performance indicated both groups were able to control their serves: however, professionals made more tactical selections and forceful executions. Shot performance indicated professionals made more successful movement to and control of shots, tactical shot selections, and forcing shot executions than novices. Overall, players' tactical response selections were greater than their forceful response executions. Thus, assessing players' decisions during competition may provide vital information concerning tactical skill development. Further, professional players exhibited higher and more consistent tactical behavior than elite collegiate players examined in 1999 by McPherson. Findings were attributed to tactical knowledge and motor skill development resulting from competition and practice experiences.  相似文献   

12.
Hollywood movies can be deeply engaging and easy to understand. To succeed in this manner, feature‐length movies employ many editing techniques with strong psychological underpinnings. We explore the origins and development of one of these, the reaction shot. This shot typically shows a single, unspeaking character with modest facial expression in response to an event or to the behavior or speech of another character. In a sample of movies from 1940 to 2010, we show that the prevalence of one type of these shots—which we call the cryptic reaction shot—has grown dramatically. These shots are designed to enhance viewers’ emotional involvement with characters. They depict a facial gesture that reflects a slightly negative and slightly aroused emotional state. Their use at the end of conversations, and typically at the end of scenes, helps to leave viewers in a state of speculation about what the character is thinking and what her thoughts may mean for the ongoing narrative.  相似文献   

13.

Objective

The IZOF-based probabilistic approach provides a methodology to study within-individual patterns of a performer's states. So far, the time course of physiological data before performance have not been investigated within the probabilistic methodology framework. The purpose of this study was to examine the value of the probabilistic approach in the assessment of the time course of physiological indicators of arousal/activation and vigilance during the period preceding the shot, in comparison with the performance-based method.

Design

Longitudinal assessment of psycho-physiological data and performance outcomes was conducted on eight elite pistol shooters in a controlled setting.

Methods

Each participant performed 60 air-pistol shots in 2 sessions. Skin conductance level and cardiac activity were recorded. Affective states intensity was evaluated on a modified 11-point Borg scale. Affect, HR and SC level were evaluated with a Performance-based approach and a Probabilistic method, and results compared at an individual level.

Results

Findings showed the higher effectiveness of the probabilistic method to analyse physiological parameters (skin conductance and heart rate) and to describe the physiological mechanisms associated with shooters’ performance.

Conclusions

The probabilistic method better discerned the contribution of arousal/activation and vigilance to optimal and non-optimal performance in elite shooters, thereby providing a sharper representation of the temporal pattern of performers' states before shooting. From an applied perspective, we believe that the probabilistic approach can help athletes become aware of the subtle variations occurring in their psychophysical states during the preparatory period preceding the shot and not only at the moment of shot release.  相似文献   

14.
15.
Differences between the multiattribute utility (MAU) profiles of participants who had previously gotten flu shots and those who had not done so were used to design an informational brochure urging influenza vaccination. The effectiveness of the MAU brochure was evaluated in a VA ambulatory care clinic with a long-standing influenza vaccination program. The target population for the intervention was high-risk clinic patients who had not gotten a shot the previous year. Participants received either a letter urging them to get a flu shot, or a letter plus the informational brochure. A significantly larger proportion of the patients who received the brochure got shots; 36% versus 23% for the letter only. While a 13 percentage point increase is modest, influenza and related complications (preventable through vaccination) are the fourth-leading killers of older persons. Adding a MAU-based brochure to an ongoing vaccination program is inexpensive and may save additional lives.  相似文献   

16.
First-order editing violations in film refer either to small displacements of the camera position or to small changes of the image size. Second-order editing violations follow from a reversal of the camera position (reversed-angle shot), leading to a change of the left–right position of the main actors (or objects) and a complete change of the background. With third-order editing violations, the linear sequence of actions in the narrative story is not obeyed. The present experiment focuses on the eye movements following a new shot with or without a reversed-angle camera position. The findings minimize the importance of editing rules which require perceptually smooth transitions between shots; there is also no evidence that changes in the left–right orientation of objects in the scene disturb the visual processing of successive shots. The observed eye movements are due either to the redirecting of attention to the most informative part on the scene or to attention shifts by motion transients in the shot. There is almost no evidence for confusion and/or for activities to restore the spatial arrangement following the reversal of the left–right positions.  相似文献   

17.
Behavior analysis procedures have been used to improve sports performance and enhance player safety across a wide variety of sports. The current study evaluated the effects of behavioral skills training on three common field hockey shots, a slap shot, drive, and sweep for young field hockey players. The procedures were evaluated in a multiple baseline across behaviors for three players. Results showed increases in each type of shot once intervention was implemented.  相似文献   

18.
Older (n = 12) and younger (n = 12) golfers attempted to hit a golf ball into a target net a short distance away. An accelerometer attached to the back of the clubhead measured the applied force. In contrast to the more typical finding of slower perceptual-motor performance by older adults, older golfers reached their peak downswing force earlier in the shot and also exhibited a trend toward a faster overall speed or tempo of the shot. Additionally, older golfers exhibited greater changes in applied force and greater variability. A pattern of divergence among the force-time histories from multiple shots suggested that the overall person-plus-golf-club dynamics were unstable during a part of the shot. Older adults may be slower in controlling this instability. Half of the participants heard a tone whose pitch was proportional to their force. These participants had a slower follow through; however, they did not make significantly more or fewer shots than participants who had not been presented with the tone. Analyses of the temporal covariation among the backswing, downswing, and follow-through favored a chain-like temporal structure over a hierarchical, proportional structure. The pattern of covariation suggests that the tempo and rhythm of the shot are not independent and that changing one's tempo may disrupt rhythm.  相似文献   

19.
ABSTRACT

The authors investigated how the force pattern exerted on a golf club is coordinated with the golfer's weight shift, which supplies power to the swing. Moderately skilled golfers (n = 10, 5–10 stroke handicap) hit short golf shots requiring different amounts of force. Across these different shots, the timing of the force pattern applied to the clubhead was approximately invariant even though the force magnitude varied. In contrast, the weight shift timing and magnitude both varied with the required force of the shot. Across repeated attempts at the same shot, temporal variations in the clubhead force pattern were either uncorrelated or only weakly correlated with temporal variations in the weight shift. Together, these data indicate that the weight shift is a relatively independent, adjustable rhythmic unit from the invariant clubhead timing pattern for moderately skilled golfers.  相似文献   

20.
Three classes of events were scored from videotapes of 14 college basketball games during the 1989 National Collegiate Athletic Association tournament: reinforcers (such as points and favorable turnovers), adversities (such as missed shots, unfavorable turnovers, and fouls), and responses to adversities (favorable or unfavorable outcomes of the first possession of the ball following an adversity). Within-game and within-team analyses of these data supported three findings. First, a team's favorable response to an adversity generally increased as the rate of reinforcement increased 3 min preceding the adversity. Second, basketball coaches called time-out from play when being outscored by their opponents an average of 2.63 to 1.0. Third, calling time-outs from play appeared to be an effective intervention for reducing an opponent's rate of reinforcement. Rates of reinforcement during the 3 min immediately after a time-out were nearly equal for both teams. Results are discussed within a behavioral momentum framework.  相似文献   

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