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1.
The surface on to which a bowler projects a ball in the game of cricket is made up of hard packed soil with sparse grass cover. This natural turf pitch is of fundamental importance to the play of the game and the quality of the surface is a prime concern of players, officials, commentators and spectators alike. A programme of research has been undertaken to identify the factors that lead to the construction of high quality cricket pitches. This work employed the technology of highspeed video analysis to monitor the performance of first class cricket pitches during county matches. A system for measuring the impact of a cricket ball on a pitch was developed, and over 3000 ball impacts analysed. This analysis enabled pitches to be characterized in terms of pace, bounce and consistency. Soil properties for the monitored pitches were identified and correlations were drawn between pitch performance and soil composition.  相似文献   

2.
Purpose: The purpose of this study was to determine the influence of eight different small-sided games (SSG) on physical, technical, and decision-making demands of training environments in U14 field hockey. Methods: A total of 13 participants played eight different training games consisting of two 7.5-minute halves, where number of players (three per side or six per side) and/or field characteristics (normal game, cage hockey game, possession game, and two-goals game) was manipulated. Match performance was determined by using notational analysis, and physical demands were determined by using GPS analyses. Results: Findings revealed that lowering the number of players increased the number of technical actions performed per player and the physical demands of the SSG. Findings of the field characteristics manipulation revealed that the possession game forced players to control the ball more as a team, which resulted in more passes (+4.82 passes) and fewer dribbles (?1.48 dribbles) and tackles (?0.69 tackles) compared to the normal game. The two-goals game led to players scoring more goals (+0.61 goals) compared to the normal game, while the cage hockey game increased passing (+1.46 passes) and physical demands (+7.32 meters per minute) compared to the normal game. Conclusion: It can be concluded from these findings that coaches and trainers are able to promote a change in playing behavior, and in turn the development of skills, by manipulating specific constraints of the training environment.  相似文献   

3.
A cricket pitch is a prepared strip of compacted soil and closely mown turf onto which the bowler projects the ball. The surface is of fundamental importance to the game and groundstaff seek to ensure that the ball rebound is of sufficient pace, bounce and consistency to promote skill in both the batsman and bowler. The scientific understanding of the factors that influence the playing quality of a pitch is incomplete and groundstaff often rely on experience and ‘rules of thumb’. A major programme of research was undertaken to determine the effectiveness of a range of pitch measurement apparatus that are perceived to provide indications of playing character. Over three seasons, 18 fieldwork visits were completed at 11 different first-class county grounds. Pitches were tested at the end of each match and direct assessments of pace, bounce and consistency were achieved by employing an artificial bowler and high speed video arrangement. Measurements of surface friction, hardness and restitution were also recorded. It was found that no single pitch measurement was able to provide a reliable indication of pace or bounce, but, when the measurements were combined in a simple Newtonian model, good predictions of pace were achieved. The study revealed a simple method by which groundstaff can predict pace during crucial stages in pitch preparation. However, the study also showed that bounce is affected by levels of pitch deformation and that development of impact models and bespoke measurement tools is needed to reliably predict variation in bounce.  相似文献   

4.
An overview of cricket ball swing   总被引：1，自引：0，他引：1  
The aerodynamic properties of a cricket ball have intrigued cricket players and spectators for years, arguably since the advent of the game itself. The main interest is in the fact that the ball can follow a curved flight path that may not always be under the control of the bowler. The basic aerodynamic principles responsible for the nonlinear flight or ‘swing’ of a cricket ball were identified decades ago and many papers have been published on the subject. Over the last 25 years or so, several empirical investigations have also been conducted on cricket ball swing, which revealed the amount of attainable swing and identified the parameters that affect it. Those findings are reviewed here with emphasis on phenomena such as late swing and the effects of humidity on swing. The relatively new concept of ‘reverse swing’, how it can be achieved in practice, and the role in it of ‘ball tampering’, are also discussed in detail. In particular, the ability of some bowlers to effectively swing an old ball in the conventional, reverse and the newly termed ‘contrast’ swing mode is addressed. A discussion of the ‘white” cricket ball used in the 1999 and 2003 World Cup tournaments, which supposedly possesses different swing properties compared to a conventional red ball, is also included. This is a current overview of cricket ball swing rather than a detailed review of all research work performed on the topic. The emphasis is on presenting scientific explanations for the various aerodynamic phenomena that affect cricket ball swing on a cricket ground.  相似文献   

5.
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6.
ABSTRACT

Visual exploratory action, in which football players turn their head to perceive their environment, improves prospective performance with the ball during match-play. This scanning action, however, is relevant for players throughout the entire match, as the information perceived through visual exploration is needed to guide movement around the pitch during both offensive and defensive play. This study aimed to understand how a player’s on-pitch position, playing role and phase of play influenced the visual exploratory head movements of players during 11v11 match-play. Twenty-two competitive-elite youth footballers (M = 16.25 years) played a total of 1,623 minutes (M = 73.8). Inertial measurement units, global positioning system units and notational analysis were used to quantify relevant variables. Analyses revealed that players explored more extensively when they were in possession of the ball, and less extensively during transition phases, as compared to team ball-possession and opposition ball-possession phases of play. Players explored most extensively when in the back third of the pitch, and least when they were in the middle third of the pitch. Playing role, pitch position and phase of play should be considered as constraints on visual exploratory actions when developing training situations aimed at improving the scanning actions of players.  相似文献   

7.
Abstract

The aim of this study was to adapt a performance measurement tool, the Team Sport Assessment Procedure (TSAP), to ice hockey during match-play. In addition to the six categories included in the original observational procedure, the ice hockey TSAP contained four new categories. Twelve Pee-Wee ice hockey matches were video-recorded during a regional championship tournament. The game play of 103 of the 11- to 12-year-old players was then analysed on video by three trained observers, based on all 10 ice hockey TSAP categories. The observational data were thereafter used to compute, for each player, a “volume of play per minute” and an efficiency index. Finally, volume of play per minute and the efficiency index were combined to obtain a composite score, the TSAP performance score. Additional measurements for each player were playing time during the observed matches, coaches’ assessments (dominant, good, less decisive), and player tournament statistics (number of points, based on assists and goals). The mean TSAP performance score was substantially higher for players rated by their coaches as dominant and for players who accumulated more than one tournament point, findings that provide evidence of the validity of the TSAP measure. In inter-observer reliability analyses of TSAP observational data provided by the trained observersfrom video recordings, the level of agreement between each pair of observers was 80–82%. Reliability correlations over a series of three matches (r=0.26, 0.59, and 0.16 respectively) showed that the TSAP performance score was relatively unstable. Ice hockey coaches may use this adapted Team Sport Assessment Procedure to better understand the offensive implication of each player in a given match, since the 10 observational variables provide more extensive information on performance than traditional statistical measures. Due to low performance stability of the TSAP performance score, coaches ought to use the observational assessment data for the formative rather than the summative assessment of their players unless they cumulate information over a series of several matches. Formative assessment can be conducted either during training camps or even during the regular season.  相似文献   

8.
Abstract

Characteristics of 32 international and 41 local under-17 (U-17) (14.5–16.5 years) roller hockey players were considered in the context of discrimination by competitive level using training history, anthropometry, skeletal maturation, and several laboratory and field performance tests. More international (42%) than local (22%) players were advanced in maturity status. International players had slightly less hockey experience (years), but had more practice sessions and match time (minutes) during the season. Local players were shorter and attained better performance in the 25-m dash, while international players performed better in sit-ups, ball throw and 20-m shuttle run. The fatigue index derived from the Wingate anaerobic test was higher among local players, while peak torques of knee extension and flexion were greater in international players. Stepwise discriminant function correctly classified 85% of players by competitive level based on grip strength, ratio of eccentric and concentric knee extension, number of training sessions, playing time and fatigue index. The results suggested an interaction among strength, anaerobic fitness and training plus game time as factors in discriminating international from local level players and by inference in the selection and development of youth roller hockey players.  相似文献   

9.
One of the tests used to evaluate the performance of sports surfaces measures the peak deceleration of a rigid mass during contact with the surface, after being dropped from a set height. It is widely used and is included in a number of international standards. The test was carried out using two drop heights on four different designs of artificial cricket pitch, with a full set of acceleration data being collected over the duration of impact. These data were then integrated twice with respect to time to produce velocity and displacement information. Oblique impacts of cricket balls were also carried out and analysed using a high-speed video system to evaluate the playing performance of each pitch design. It was found that, although the pitches gave quite different readings of peak deceleration, they produced similar values for coefficient of restitution and were therefore considered to ‘play’ in a very similar way. This was due to a high peak deceleration reading being accompanied by a short contact time and low peak deceleration being accompanied by a long contact time, meaning that the change in momentum was similar in both cases. It was concluded that for accelerometer tests to be useful, all the acceleration-time data should be analysed, rather than the peak value alone.  相似文献   

10.
Abstract

This study examined the influence of pitch dimensions in small-sided soccer games in shaping opportunities for performers to maintain ball possession, pass to teammates and shoot at goal. Fifteen amateur standard male participants (M = 21.87, σ = 1.96 years) played 5 v 5 small-sided soccer games in three varying pitch conditions (28 m × 14 m, 40 m × 20 m and 52 m × 26 m). Thirty sequences of play in each condition were selected for digitisation using TACTO software, allowing the capture of bi-dimensional displacement coordinate data of all players and the ball. The values of interpersonal distance between all attackers and immediate defenders and the relative distances of defenders to intercept a shot and a pass were computed as dependent variables. Results showed existence of fewer opportunities to maintain ball possession on smaller pitches, compared to medium and larger pitches. Conversely, the different dimensions set to the pitch did not influence opportunities for players to shoot at goal, or to perform passes to other teammates. By examining the specific spatial–temporal relationships of players and key-task constraints, the data from this study explain how effects of manipulating pitch dimensions of small-sided games might enhance opportunities for acquiring specific movement and decision-making skills.  相似文献   

11.
唐金根  李彬 《体育科技文献通报》2012,20(10):54+68-54,68
采用文献资料、录像统计以及数据分析对比等研究方法,对2011男篮亚锦赛复赛阶段归化球员在比赛中的各项数据进行研究。研究分析表明：在有归化球员的球队中,归化球员基本都有支配球的权利与能力。在进攻的出手次数统计中归化球员要远高于平均值,且归化球员的命中率直接与比赛的胜负相关。  相似文献   

12.
Many slo-pitch coaches and players believe that generating spin on a ball can affect its trajectory. The influence of air resistance on a ball that is thrown at a moderate speed and spin is unclear. The aim of this study was to examine the influence of spin on the ball's trajectory in slo-pitch pitching using both experimental results and ball flight simulations. Fourteen pitchers participated in the study, each of whom threw five backspin and topspin pitches each. Data were collected using standard three-dimensional videography. The horizontal velocity, vertical velocity, angular velocity, release height, and horizontal displacement of the backspin pitches were significantly higher than those of the topspin pitches. The ball flight simulations were developed to examine the influence of the ball spin, and it was concluded that the spin of the ball had a significant effect on the ball's vertical and horizontal displacements. Furthermore, our results suggest that a backspin pitch that reaches the maximum height allowable and lands in the front edge of the strike zone has the steepest slope. The present results add to our understanding of projectile motion and aerodynamics.  相似文献   

13.
ABSTRACT

Videogames often confront players with frustratingly difficult challenges, fearsome enemies, and tragic stories. As such, they can evoke feelings of failure, sadness, anger, and fear. Although these feelings are usually regarded as undesirable, many players seem to enjoy videogames which cause them. In this paper, I argue that player misery often originates from a fictional or lusory attitude which brackets game events from real-life, making the player’s emotions solely relevant within the game context. As they are part of the game themselves, these negative emotions can be enjoyed and easily relativized, since players can acknowledge that their cause is ‘only a game’. However, there are feelings of misery associated with the playing of videogames which are not caused by either the game’s fiction or challenge. In the last part of this paper, I describe a qualitatively different kind of player misery: one that is caused by elements that are not perceived as part of the game by the player, and is not bracketed from real life by a lusory or fictional attitude.  相似文献   

14.
Many slo-pitch coaches and players believe that generating spin on a ball can affect its trajectory. The influence of air resistance on a ball that is thrown at a moderate speed and spin is unclear. The aim of this study was to examine the influence of spin on the ball's trajectory in slo-pitch pitching using both experimental results and ball flight simulations. Fourteen pitchers participated in the study, each of whom threw five backspin and topspin pitches each. Data were collected using standard three-dimensional videography. The horizontal velocity, vertical velocity, angular velocity, release height, and horizontal displacement of the backspin pitches were significantly higher than those of the topspin pitches. The ball flight simulations were developed to examine the influence of the ball spin, and it was concluded that the spin of the ball had a significant effect on the ball's vertical and horizontal displacements. Furthermore, our results suggest that a backspin pitch that reaches the maximum height allowable and lands in the front edge of the strike zone has the steepest slope. The present results add to our understanding of projectile motion and aerodynamics.  相似文献   

15.
The aim of this study was to compare match analysis (using video recordings) and the physiological load (heart rate measured every 5s, blood lactate measured after the warm-up, first half and second half) of six 11-year-old soccer players during official games of eleven-a-side on a regular-sized pitch (100×65m) and of seven-a-side on a smaller pitch (60×40m). In both games, heart rate exceeded 170 beats·min-1 84% of the time, while blood lactate ranged from 1.4 to 8.1 mmol·l-1 . No significant differences were recorded for the physiological parameters. For both matches, walking comprised 38% of total time, running 55%, inactivity 3% and jumping 3%. Although there were no significant differences between halves or matches, running for less than 10s was 10% more frequent in the seven-a-side game. In the seven-a-side game, there were significantly more passes and significantly fewer tackles, suggesting that seven-a-side matches played on smaller pitches may be more suitable for pre-pubescent soccer players.  相似文献   

16.
ABSTRACT

Studies in several sports have shown the benefits of adapting the playing environment to fit junior players. Frequently the changes are pragmatic choices based on space constraints or existing line markings, or the result of simple scaling based on stature. In this study, a method of scaling the cricket pitch length is presented which is based on the age-specific size and performance of the bowlers and batters. The objective was a pitch length which enabled young bowlers to bowl good length deliveries while releasing the ball at a more downward angle, similar to elite bowlers. The steeper release angle has the benefit of reducing the sensitivity of the ball flight distance to the variability of ball release. Based on data from county standard under-10 and under-11 players a pitch length of 16.22 yards (14.83 m) was calculated, 19% shorter than previously recommended for under-11s in England. A shorter pitch also increases the temporal challenge for batters, encouraging a wider variety of shots and improved anticipation skills. Pitch lengths scaled in this way to fit the players’ abilities as they develop will enable a more consistent ball release by bowlers and more consistent temporal demand for batters.  相似文献   

17.
In order to get bounce and movement seam bowlers need to bowl the ball “into” the pitch. Standard deliveries by elite players are typically projected at around 7° below horizontal. In contrast, young players currently often need to release the ball almost horizontally in an effort to get the ball to bounce close enough to the batter. We anticipated that shortening the pitch could be a simple way to help young bowlers to release the ball at a better angle and with more consistency. Twenty county or best in club age group under 10 and under 11 seam bowlers were analysed bowling indoors on two different pitch lengths. They were found to project the ball on average 3.4° further below horizontal on a 16 yard pitch compared with a 19 yard pitch, while ball speed and position at release changed negligibly. Pitch length did not affect the consistency of the release parameters. The shorter pitch led to a ball release angle closer to that of elite bowlers without changing release speed, and this should enable players to achieve greater success and develop more variety in their bowling.  相似文献   

18.
Goaltenders in ice hockey are the only players that are on the ice for the entire game. Their position exposes them to impacts from collisions with other players, falls to the ice, and puck impacts. In competitive ice hockey leagues, head injuries resulting from puck impacts have been reported with some cases resulting in ending the player’s career. Considerable research has been conducted to assess the performance of hockey helmets; however, few have assessed the performance of goaltenders’ masks. The purpose of this study was to compare the capacity of four goaltenders’ masks for the protection from puck impact as measured by head acceleration and peak force. A Hybrid III headform was fitted with four different goaltender masks and impacted with a hockey puck in three locations at 25 m/s. The masks were found to vary in the level of protection they offered as the mask with the thickest liner resulted in lower forces than the thinnest mask for side impacts; however, the thinnest mask resulted in the lowest force for front impacts. Despite performance differences at specific locations, no one mask proved to be superior as peak acceleration and peak force values did not exceed the thresholds necessary for concussion.  相似文献   

19.
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20.
This study is situated within an existential–narrative theoretical framework to examine the impact of career-threatening injury on professional ice hockey players’ well-being and career construction. Professional ice hockey culture is construed as a privileged space characterised by hegemonic masculinity, fierce competition as well as high-risk behaviours often resulting in sports injuries. In this paper, we analyse two players’ life stories with a particular focus on injury as a boundary situation involving social and temporal breakdown and re-evaluation of meaning of sporting life projects. Emergent narratives surrounding existential themes of loss of meaning and loneliness in the face of injury were analysed in connection with players’ search for authenticity and realignment with self-concept. Each player developed resistant narratives to the dominant ethos of professional sport in order to restore well-being and sense of self. The relational aspects of injury are highlighted in practical recommendations.  相似文献   

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