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1.
In this paper, we identify appropriate statistical methods for analysing categorical differences in discrete variables or 'performance indicators' resulting from performance analysis. The random mechanisms associated with discrete events do not follow a normal distribution; that is, the normal distribution is a continuous not a discrete probability distribution. We propose appropriate statistical methods based on two key discrete probability distributions, the Poisson and binomial distributions. Two approaches are proposed and compared using examples from notational analysis. The first approach is based on the classic chi-square test of significance (both the goodness-of-fit test and the test of independence). The second approach adopts a more contemporary method based on log-linear and logit models fitted using the statistical software GLIM. Provided relatively simple one-way and two-way comparisons in categorical data are required, both of these approaches result in very similar conclusions. However, as soon as more complex models or higher-order comparisons are required, the approach based on log-linear and logit models is shown to be more effective. Indeed, when investigating those factors and categorical differences associated with binomial or binary response variables, such as the proportion of winners when attempting decisive shots in squash or the proportion of goals scored from all shots in association football, logit models become the only realistic method available. By applying log-linear and logit models to discrete events resulting from notational analysis, greater insight into the underlying mechanisms associated with sport performance can be achieved.  相似文献   

2.
The aim of this study was to examine the effects of match location, quality of opposition, and match status on the technical aspects of performance within a single professional British football team. Forty matches from the 2002--2003 and 2003--2004 domestic league seasons were notated post-event using a computerized notational analysis system with 13 on-the-ball behaviours and corresponding outcomes (successful or unsuccessful) assessed. Log-linear modelling procedures indicated that the incidences of all on-the-ball technical behaviours, with the exception of "set-pieces", were influenced by at least one of the three situation variables, with both independent and interactive effects found. In contrast, logit modelling suggested that there was no general influence of the situation variables on the outcomes of the on-the-ball behaviours. The findings emphasize the need for notational analysts and coaches to consider the potential independent and interactive effects of match location, quality of opposition, and match status when assessing the technical components of football performance, particularly those relating to behaviour occurrence. Future research should consider the effects of additional situation variables purported to influence the mental, physical, technical, and tactical components of football performance.  相似文献   

3.
Abstract

The aim of this study was to examine the effects of match location, quality of opposition, and match status on the technical aspects of performance within a single professional British football team. Forty matches from the 2002–2003 and 2003–2004 domestic league seasons were notated post-event using a computerized notational analysis system with 13 on-the-ball behaviours and corresponding outcomes (successful or unsuccessful) assessed. Log-linear modelling procedures indicated that the incidences of all on-the-ball technical behaviours, with the exception of “set-pieces”, were influenced by at least one of the three situation variables, with both independent and interactive effects found. In contrast, logit modelling suggested that there was no general influence of the situation variables on the outcomes of the on-the-ball behaviours. The findings emphasize the need for notational analysts and coaches to consider the potential independent and interactive effects of match location, quality of opposition, and match status when assessing the technical components of football performance, particularly those relating to behaviour occurrence. Future research should consider the effects of additional situation variables purported to influence the mental, physical, technical, and tactical components of football performance.  相似文献   

4.
Abstract

The possible utilization of item response theory (IRT) and adaptive testing in psychomotor situations leads to a number of interesting suppositions. The question of test validity is crucial and the application of those procedures could help enhance the quality and generalizability of research results.

Examination of the results of several previous studies indicates that adaptive testing may be easily applied in a number of psychomotor problems. The application of IRT will depend upon the type of model chosen. Various models are considered from a heuristic standpoint with the binomial model being the most logically suitable approach. The continuous response model needs to be examined more thoroughly.

The combination of selected IRT models with other approaches such as sequential probability testing and trials-to-criterion testing was discussed. The use of validity generalization was suggested. It was concluded that in order for approaches of this type to be feasible, researchers needed to construct more scientifically rigorous theories.  相似文献   

5.
Frequent violations of the assumption that data are normally distributed occur in exercise science and other life and behavioral sciences. When this assumption is violated, parametric statistical analyses may be inappropriate for data analysis. We provide a rationale for using a generalized form of nonparametric analyses based on the Puri and Sen (1985) L treated as a chi 2 approximation. If data do not meet the assumption of normality, this nonparametric approach has substantial power and is easy to use. An advantage of this generalized technique is that ranked data may be used in standard parametric statistical programs widely available on desktop and mainframe computers, for example, regression, analysis of variance (ANOVA), multivariate analysis of variance (MANOVA) within BioMed, SAS, SPSS. Once the data are ranked and analyzed with these programs, the only adjustment required is to use a standard formula to calculate the nonparametric test statistic, L, instead of the parametric test statistic (e.g., F). Thus, rank-order nonparametric models become parallel with their parametric counterparts allowing the researcher to select between them based on characteristics of the data distribution. Examples of this approach are provided using data from exercise science for regression, ANOVA (including repeated measures) and MANOVA techniques from SPSSPC. Using these procedures, researchers can easily examine data distributions and make an appropriate decision about parametric or nonparametric analyses while continuing to use their regular statistical packages.  相似文献   

6.
In 1999, Wilson and Batterham proposed a new approach to assessing the test–retest stability of psychometric questionnaires. They recommended assessing the proportion of agreement – that is, the proportion of participants that record the same response to an item – using a test–retest design. They went on to use a bootstrapping technique to estimate the uncertainty of the proportion of agreement. The aims of this short communication are (1) to demonstrate that the sampling distribution of the proportion of agreement is well known (the binomial distribution), making the technique of ‘bootstrapping’ redundant, and (2) to suggest a much simpler, more sensitive method of assessing the stability of a psychometric questionnaire, based on the test–retest differences (within-individuals) for each item. Adopting methods similar to Wilson and Batterham, 97 sport students completed the Social Physique Anxiety Scale on two occasions. Test–retest differences were calculated for each item. Our results show that the proportion of agreement ignores the nature of disagreement. Items 4 and 11 showed similar agreement (44.3% and 43.3% respectively), but 89 of the participants (91.8%) differed by just - 1 point when responding to item 4, indicating a relatively stable item. In contrast, only 78 of the participants (80.4%) recorded a difference within - 1 point when responding to item 11, suggesting quite contrasting stability for the two items. We recommend that, when assessing the stability of self-report questionnaires using a 5-point scale, most participants (90%) should record test–retest differences within a reference value of - 1.  相似文献   

7.
探索不同赛制下比赛表现指标对比赛结果产生的影响,选取2018年俄罗斯世界杯59场、118组技战术表现和跑动表现指标作为自变量,比赛胜、负作为因变量。运用K型聚类分析,对比分均衡比赛进行界定。根据比赛控球率的不同对比赛表现指标进行标准化处理。运用数据级数推断法界定各自个变量增加2个标准差对比赛获胜概率带来的变化。研究结果:1)在所有比赛中,9项技战术表现指标(射门次数、射正次数、射正率、定位球射门次数、突破进入罚球区次数、控球率、传球成功率、解围成功次数和防守反击次数)和3项跑动表现指标(本方控球时跑动距离、进攻三区跑动距离和对方罚球区跑动距离)使比赛获胜概率显著提升。对方控球时跑动距离则使获胜概率显著下降;2)在比分均衡比赛中,5项技战术表现指标(射门率、定位球射门次数、控球率、传球成功率和解围成功次数)和3项跑动表现指标(本方控球时跑动距离、进攻三区跑动距离和对方罚球区跑动距离)使比赛获胜概率显著提升。而向前传球次数、低强度跑距离、中强度跑距离、对方控球时跑动距离4项比赛表现指标则使获胜概率显著下降。研究表明,FIFA世界杯获胜球队在立足于防守的基础上,以防守反击和定位球作为主要进攻和得分手段,表现出与联赛球队不同的比赛策略。因此,各级球队在备战时应根据赛制和对手实力情况作出针对性的战术部署。  相似文献   

8.
ABSTRACT

The literature on momentum is still undecided, with mixed results whether momentum exists or is only perceived to exist (“hot hand fallacy”). We explore whether momentum exists by looking at cases in which a basketball player has three consecutive free throws. A free throw is a well-defined task executed in a stable environment, allegedly giving momentum optimal chances to occur. Taking 14 NBA seasons we collected over 4500 three-free-throw sets (triplets). We obtained the outcomes of the shots as well as some additional variables about the player and the game: the player’s average free-throw percentage, home or away, and the game score and the quarter when the free throws were attempted. We first analyse the hit rates in the three shots and then proceed to regression analysis that also controls for the abovementioned variables. We address several concerns raised in the literature. All comparisons and analyses yield the same conclusion that there is no evidence for momentum in the data.  相似文献   

9.
Abstract

The purpose of this study was to compare the effectiveness of learning between two distributions of practice in archery and badminton classes. Each activity was divided into two groups based on the distribution of practice used. The “t” test of the significance of the difference between means was used to make comparisons between groups relative to the effectiveness of the two practice distributions of learning as measured by gain in selected criteria. The results seemed to indicate that more effective learning in archery took place under relatively massed practice while in badminton wider distribution of practice produced more rapid learning.  相似文献   

10.
The kinematics of the racket and ball near impact in tennis forehands were studied to document typical variation in successful and unsuccessful shots, in order to determine biomechanically meaningful differences in advanced players and confirm models of groundstroke trajectories. Seven tennis players (six males and one female) were videoed from the side at 180 Hz as they performed 40 forehand drives on an indoor tennis court. Vertical plane kinematics of the racket and ball near impact were analysed for sub samples of successful and unsuccessful shots for each subject. Most racket kinematic variables were very consistent (mean CV< 6.3%) for successful shots, so bio mechanically meaningful differences in angles and velocities of the racket and ball (3° and 2 m s−1) near impact could be detected between successful and unsuccessful shots. Four subjects tended to miss long and three subjects missed shots in the net that were reflected in initial ball trajectories. Mean (SD) initial trajectories for long shots were 9.8° (1.4°), while netted shots were 0.7° (1.1°) above the horizontal. The initial ball trajectories and margins for error for these subjects were smaller than those previously reported (Brody, 1987) because players tended to select mean ball trajectories close to one error than another, differing amounts of topspin, or incorrect lift and drag coefficients for tennis balls had not been published when this model was created. The present data can be used to confirm if recent models (Cookeet al., 2003; Dignallet al., 2004) more closely match actual performance by advanced players.  相似文献   

11.
ABSTRACT

Spatio-temporal data in sport is increasing rapidly, however suitable statistical methods for analysing this data are underdeveloped. The current study establishes the need for spatial statistical methods, propose a Bayesian hierarchical model as an appropriate method for comparing spatial variables, and test this model across three spatial scales. The need for spatial statistical methods was established through the identification of spatial autocorrelation. This necessitated the use of a Bayesian hierarchical model to test for an association between spatial ball movement entropy and spatial effectiveness. Posterior distribution results showed a generally positive association such that increases in entropy were associated with increases in effectiveness. The strength and confidence of the associations were impacted by the spatial scale, with the 6 × 6 grid showing the most conclusive evidence of a positive relationship; the 4 × 4 grid was mostly positive, however with a large variation; and finally, the basket-centric scale results were less conclusive. The results of the current study demonstrate the suitability of a Bayesian hierarchical model for testing for associations or differences between spatial variables. With the increase in spatial analyses in sport, this study presents an appropriate statistical method for dealing with complex problems associated with spatial analyses.  相似文献   

12.
Two current approaches frequently implemented to understand mechanisms involved in motor control are presented in a series of papers. One approach aims at understanding what specific neural mechanisms are responsible for motor behavior Such neural mechanisms might be operative at any of several sites in the nervous system, including spinal sites capable of complex reflex organization, as well as supraspinal sites involved in integrating multiple sensory and motor processes. Alternative approaches involve the assessment of kinematic and other variables used to describe the behavior using dynamical systems theory. Such an approach allows the researcher to explore relationships among groups of variables in, for example, multijoint control. In the series of papers that follow, the value of both of these approaches is discussed using examples from tasks that involve both rhythmic activities (running and cycling) and discrete movement (weight lifting and golf).  相似文献   

13.
In golf, unlike most other sports, individual performance is not the result of direct interactions between players. Instead decision-making and performance is influenced by numerous constraining factors affecting each shot. This study looked at the performance of PGA TOUR golfers in 2011 in terms of stability and variability on a shot-by-shot basis. Stability and variability were assessed using Recurrence Quantification Analysis (RQA) and standard deviation, respectively. About 10% of all shots comprised short stable phases of performance (3.7 ± 1.1 shots per stable phase). Stable phases tended to consist of shots of typical performance, rather than poor or exceptional shots; this finding was consistent for all shot categories. Overall, stability measures were not correlated with tournament performance. Variability across all shots was not related to tournament performance; however, variability in tee shots and short approach shots was higher than for other shot categories. Furthermore, tee shot variability was related to tournament standing: decreased variability was associated with better tournament ranking. The findings in this study showed that PGA TOUR golf performance is chaotic. Further research on amateur golf performance is required to determine whether the structure of amateur golf performance is universal.  相似文献   

14.
Abstract

Academics have a responsibility to ensure that their research findings are as truthful as possible. InIn every issue of a scientific journal, a large number of significance tests are reported (usually using P <0.05). Of course, most of these results will be true/correct. Unfortunately, due to the nature of sampling, researchers will occasionally make errors, often referred to as type I (probability = α) and type II (probability = β) errors. The power of a test (1-β) is the probability of correctly rejecting a false null hypothesis – that is, correctly detecting a real or true effect. Factors that are known to influence power include: (1) the level of significance (α), (2) the size of the difference or relationship in the population (the effect), (3) the sample size, and (4) unexplained error variance. As researchers, we have little control over most of these factors. The one factor that we have some influence over, however, is the ability to reduce the unexplained error variance. In the present article, we describe a range of methods that will increase the probability that a researcher has correctly identified a real effect by increasing the power of their statistical tests. Such methods will include ways of designing experiments to reduce error and uncertainty. The use of blocking and randomized block designs will reduce unexplained error, such as adopting matched or repeated-measures designs rather than using independent observations. The other method of reducing unexplained errors is to adopt more appropriate (e.g. biologically correct) models and checking the distribution assumptions associated with such models. In conclusion, researchers are responsible for maximizing the likelihood that their results are as accurate and truthful as possible. By carefully planning their experiments and adopting appropriate models, researchers are more likely to publish their findings with a greater degree of confidence, but not certainty.  相似文献   

15.
Shots are an essential part of the language of tennis yet little is known about the distinct types of shots in the professional game. In this study, we build a taxonomy of shots for elite tennis players using tracking data from multiple years of men’s and women’s matches at the Australian Open. Our taxonomy is constructed using model-based multi-stage functional data clustering, an unsupervised machine learning approach. Among 270,023 men’s and 178,136 women’s shots, we found 13 distinct types of serves to both the Ad and Deuce court for male players and 17 and 15 types to the Ad and Deuce for female players. More variety was found among serve returns and rally shots compared to the serve; with less variety on the backhand than forehand. There was also more overlap in the physical characteristics of groundstroke shots between male and female players than on serve. Shot type was strongly associated with winning points and shots in the highest speed and lowest net clearance categories tended to be the most effective. This data-driven dictionary of shots provides a framework for analysis of elite player performance, characterizing playing style, and designing more representative practice.  相似文献   

16.
The goal of this research was to develop a method to quantify the dynamic strain profile (DSP) of an ice hockey stick shaft and assess the potential influence of player skill and stick shaft stiffness on DSP during slap (SS) and wrist shots (WS). Seventeen adult males performed shots with two different stick stiffness’ on synthetic ice. Subjects were subdivided as high (HC) and low calibre (LC). Dependent measures included strain measures from five strain gauge pairs along the shaft length recorded at 10 kHz. In general, this approach was sufficiently sensitive to clearly distinguish between shot types (strains SS > WS), player calibre (strains HC > LC) and stick models (strain flex77 > flex102) as well as to identify within stick deflection differences along the shaft. This strain based analysis has a time and spatial resolution undetected by common motion capture based systems.  相似文献   

17.
The popular method of organising youth sport participants into age divisions, based solely on their birthdate, can result in an imbalance of the distribution of players. This is known as relative age effect (RAE), which inadvertently creates bias and is associated with deleterious short and long-term consequences. The overall purpose of this study was to examine how the potential for RAE is mitigated when simultaneously accounting for additional player criterion, supplementary to age. A mid-Atlantic American youth football registration database was acquired, including chronological (age), anthropometric (weight), and competency (skill) factors. Player (n = 1,265) data were classified into quartiles and multiple chi-square goodness of fit tests were conducted using proportions of live births as expected theoretical distribution values. When data were categorised by a single developmental criterion (e.g. age), results indicated significant departures (p ≤ 0.002) from expected proportions. However, when categorised using multiple criteria (i.e. age, weight, and skill), equitable birthdate distributions were observed. Findings from this study indicate using only one developmental criterion for organising players is associated with RAE, whereas approaches accounting for multiple variables are not associated with RAE. This study provides youth football programs with early evidence for considering alternative methods of organising players.  相似文献   

18.
In 1999, Wilson and Batterham proposed a new approach to assessing the test-retest stability of psychometric questionnaires. They recommended assessing the proportion of agreement - that is, the proportion of participants that record the same response to an item - using a test-retest design. They went on to use a bootstrapping technique to estimate the uncertainty of the proportion of agreement. The aims of this short communication are (1) to demonstrate that the sampling distribution of the proportion of agreement is well known (the binomial distribution), making the technique of 'bootstrapping' redundant, and (2) to suggest a much simpler, more sensitive method of assessing the stability of a psychometric questionnaire, based on the test-retest differences (within-individuals) for each item. Adopting methods similar to Wilson and Batterham, 97 sport students completed the Social Physique Anxiety Scale on two occasions. Test-retest differences were calculated for each item. Our results show that the proportion of agreement ignores the nature of disagreement. Items 4 and 11 showed similar agreement (44.3% and 43.3% respectively), but 89 of the participants (91.8%) differed by just +/-1 point when responding to item 4, indicating a relatively stable item. In contrast, only 78 of the participants (80.4%) recorded a difference within +/- 1 point when responding to item 11, suggesting quite contrasting stability for the two items. We recommend that, when assessing the stability of self-report questionnaires using a 5-point scale, most participants (90%) should record test-retest differences within a reference value of +/- 1.  相似文献   

19.
“体育科学研究方法”专栏的开设始自张力为博士的一个想法。当时我曾委托他为本刊主持一个专题，而对学问严肃又负责的他却迟迟没有组到自认为合格的稿子。交流中我们谈起目前体育学术界在研究方法上存在的问题种种，不久就有了他的12篇关于研究方法的文章寄来，看来他已是厚积薄发。于是，我们想索性办个专栏，引发更多学者的关注和参与。我们请姜达维教授审阅了张博士的文章，便有了网上精彩的对话和更多思想火花的进发。“体育科学研究方法”专栏就在这样一个充满激情与智慧的讨论中开场了。  相似文献   

20.
研究问题与统计方法的有机配合   总被引：7，自引：0，他引：7  
在实证性研究的设计阶段．研究者应明确研究课题，界定自变量、因变量、控制变量和协变量的操作定义和相互关系，并根据研究课题和变量关系选择合适的统计技术。分别讨论了分析变量关系、探讨组间差异、预测组别隶属以及考察变量结构这四类统计技术解答的研究问题，并通过科研实例介绍了根据研究问题选择统计技术的思路。特别指出。一个研究问题通常可以由多个统计方法加以解决。  相似文献   

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