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Benjamin K. Williams Ross H. Sanders Joong Hyun Ryu Philip Graham-Smith Peter J. Sinclair 《Journal of sports sciences》2020,38(10):1115-1123
ABSTRACT To maintain the accuracy of squash shots under varying conditions, such as the oncoming ball’s velocity and trajectory, players must adjust their technique. Although differences in technique between skilled and less-skilled players have been studied, it is not yet understood how players vary their technique in a functional manner to maintain accuracy under varying conditions. This study compared 3-dimensional joint and racket kinematics and their variability between accurate and inaccurate squash forehand drives of 9 highly skilled and 9 less-skilled male athletes. During inaccurate shots, less-skilled players hit the ball with a more open racket, demonstrating a difference in this task-relevant parameter. No joint kinematic differences were found for accuracy for either group. Coordinated joint rotations at the elbow and wrist both displayed a “zeroing-in” effect, whereby movement variability was reduced from the initiation of propulsive joint rotation to a higher consistency at ball-impact; potentially highlighting the “functionality” of the variability prior to the impact that enabled consistent task-relevant parameters (racket orientation and velocity) under varying conditions. Further, highly skilled players demonstrated greater consistency of task-relevant parameters at impact than less-skilled players. These findings highlight the superior ability of highly skilled players to adjust their technique to achieve consistent task-relevant parameters and a successful shot. 相似文献
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Analysis of competitive sport performance from a priori observation is frequently used to prepare an athlete for a future contest. This practice necessarily assumes that the observed athletic behaviours are invariant, in that the data from an earlier contest apply to the next. We report different analyses of championship squash matches from 1987 and 1988 in search of such invariance and thus a general signature of athletic behaviour. The results show that once the preceding condition to an athletic response (shot) becomes more detailed, by either accounting for where on court the previous shot was played to, or by pairing the previous shot with its own antecedent, the corresponding response becomes more predictable (P > 0.25). This is especially the case for a squash champion when the forehand and backhand characteristics of his shot response are accounted for. The finding that the champion is more consistent if his forehand and backhand shot responses to a preceding shot are analysed separately, shows that the level of analytic detail is an important consideration if the derived information from sport analysis is to prepare an athlete reliably for future sport competition. Finally, we consider sport competition from an ecological perspective with regard to the natural organization and stability of non‐linear systems in an attempt to explain the empirical data. 相似文献
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赵荣乐 《上海大学学报(英文版)》2000,4(2):171-174
1 Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｓｑｕａｓｈｍｏｓａｉｃｖｉｒｕｓ (ＳｑＭＶ)ｉｓｏｎｅｏｆｔｈｅｍｏｓｔｉｍ ｐｏｒｔａｎｔｃｕｃｕｒｂｉｔｖｉｒｕｓｅｓ[1～ 3] ,ａｎｄｉｔｃａｕｓｅｓｇｒｅａｔｌｏｓｓｅｓｉｎｍｕｓｋｍｅｌｏｎｐｒｏｄｕｃｔｉｏｎ[4 ] .Ｏｎｅｏｆｔｈｅｍａｉｎｗａｙｓｔｏｃｏｎｔｒｏｌｐｌａｎｔｖｉｒｕｓｄｉｓｅａｓｅｓｉｓｔｈｅｉｎｄｕｃｅｍｅｎｔｏｆｒｅｓｉｓ ｔａｎｃｅｔｏｖｉｒｕｓｅｓ[5] ｂｙｓｏｍｅｂｉｏｌｏｇｉｃａｌａｎｄｎｏｎ ｂｉｏｌｏｇｉｃａｌｆａｃｔｏｒｓ[6～ 9… 相似文献
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杜宁 《吉林体育学院学报》2011,27(3):61-63
通过文献资料、问卷调查、访谈等研究方法,对辽宁省群众性壁球运动开展的现状进行调研分析,研究结果表明辽宁省群众性壁球运动开展是以城市的经济、文化发展水平为基础,以企事业单位的中、壮年工作人员为主要群体。目前辽宁省内各市的壁球场馆较少、缺乏专职教练,对辽宁省群众性壁球运动的开展普及有阻碍作用。 相似文献
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《European Journal of Sport Science》2013,13(2):129-140
Abstract The velocities and distances covered by players during competition serve as a basis for planning fitness regimes according to the specific demand of the sport. The techniques used to calculate these movement parameters have ranged from human judgements to technological solutions such as GPS and computer vision. This paper evaluates the accuracy of a computerized motion tracking system (SAGIT/Squash) that uses computer vision methods on video captured via a fixed single camera located centrally above the court. Digital images were processed automatically with operator supervision so that any tracking errors could be rectified and manual tagging of all shots added. Four separate experiments were used to assess the error associated with tracking adult players' velocities and positions with respect to the court floor. Experiment 1 involved players standing still in different areas of the court. The tracking software was found to be more accurate when a player was stood in the centre of the court (1.33 m · min?1 error) than in the corners (2.61 m · min?1 error), predominately due to systematic errors (e.g. calibration). Experiment 2 was conducted in the same manner as Experiment 1 except that the players vigorously swung a racket around their body continuously. This resulted in 15 times the error found in Experiment 1 for the distance covered during 1 min. However, this is an unrealistic estimate of the true error when assessing matches, as during matches the racket is only swung approximately 35% of the time. Experiment 3 involved a player running at different speeds around a rectangular path on the court. The resultant trajectory, as captured by the software, was compared using different Gaussian smoothing equations of kernel widths 0.25 s, 0.5 s, and 1 s. The best solution (0.5 s) resulted in the most accurate trajectory, although the difference in distance calculated between the different equations was negligible. Experiment 4 used the 0.5-s smoothing equation to assess the tracking accuracy for a player running at a relatively steady speed in a more realistic circular trajectory. The trajectory of the pixel image was shown to have a smaller radius than the reference trajectory at increased speeds, due to the tendency of the player to lean over when negotiating a circular path. The error associated with the distance covered over 1 min was shown to range between 1.33 and 21 m depending on the nature and position of the player's movements. Values, typically somewhere in this range, are likely to be evident during typical use of this software. 相似文献
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Stafford Murray Janez Perš Rok Mandeljc Goran Vučković 《Journal of sports sciences》2018,36(12):1415-1422
Situation awareness (SA) refers to the awareness of all relevant sources of information, an ability to synthesise this information using domain knowledge gained from past experiences and the ability to physically respond to a situation. Expert-novice differences have been widely reported in decision-making in complex situations although determining the small differences in expert behaviour are more elusive. This study considered how expert squash players use SA to decide on what shot to play. Matches at the 2010 (n = 14) and 2011 (n = 27) Rowe British Grand Prix were recorded and processed using Tracker software. Shot type, ball location, players’ positions on court and movement parameters between the time an opponent played a shot prior to the player’s shot to the time of the opponent’s following shot were captured 25 times per second. Six SA clusters were named to relate to the outcome of a shot ranging from a defensive shot played under pressure to create time to an attempted winner played under no pressure with the opponent out of position. This new methodology found fine-grained SA differences in expert behaviour, even for the same shot type played from the same court area, beyond the usual expert-novice differences. 相似文献
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