A. Mark Williams

Practice, instruction and skill acquisition in soccer: Challenging tradition

The acquisition of soccer skills is fundamental to our enjoyment of the game and is essential to the attainment of expertise. Players spend most of their time in practice with the intention of improving technical skills. However, there is a lack of scientific research relating to the effective acquisition of soccer skills, especially when compared with the extensive research base on physiological aspects of performance. Current coaching practice is therefore based on tradition, intuition and emulation rather than empirical evidence. The aim of this review is to question some of the popular beliefs that guide current practice and instruction in soccer. Empirical evidence is presented to dispel many of these beliefs as myths, thereby challenging coaches to self-reflect and critically evaluate contemporary doctrine. The review should inform sports scientists and practitioners as to the important role that those interested in skill acquisition can play in enhancing performance at all levels of the game.

What is modelled during observational learning

Abstract In this article, we examine the question of what information is processed during observational learning by evaluating a variety of methods, theories, and empirical data. Initially, we review work involving neuroimaging techniques and infant imitation. We then evaluate data from behavioural experiments involving adults, wherein a variety of attempts have been made to isolate the critical or minimal information constraining the acquisition of coordination. This body of research has included comparisons between video and point-light displays, manipulations to the amount and type of information presented in the display, the collection of point-of-gaze data, and manipulations to the task context in terms of outcome goals. We conclude that observational learning is governed by specific features of the models action (i.e. motions of the end effector) and the task (i.e. outcome constraints) and, in contrast with traditional theoretical modelling, more global aspects of a model (i.e. the relative motions within and between joints) do not appear to be the primary method for constraining action execution.

Learning from demonstrations: the role of visual search during observational learning from video and point-light models

In this study, we examined the visual search strategies used during observation of video and point-light display models. We also assessed the relative effectiveness of video and point-light models in facilitating the learning of task outcomes and movement patterns. Twenty-one female novice soccer players were divided equally into video, point-light display and no-model (control) groups. Participants chipped a soccer ball onto a target area from which radial and variable error scores were taken. Kinematic data were also recorded using an opto-electrical system. Both a pre- and post-test were performed, interspersed with three periods of acquisition and observation of the model. A retention test was completed 2 days after the post-test. There was a significant main effect for test period for outcome accuracy and variability, but observation of a model did not facilitate outcome-based learning. Participants observing the models acquired a global movement pattern that was closer to that of the model than the controls, although they did not acquire the local relations in the movement pattern, evidenced by joint range of motion and angle-angle plots. There were no significant differences in learning between the pointlight display and video groups. The point-light display model group used a more selective visual search pattern than the video model group, while both groups became more selective with successive trials and observation periods. The results are discussed in the context of Newells hierarchy of coordination and control and Scully and Newells visual perception perspective.

The efficacy of demonstrations in teaching children an unfamiliar movement skill: The effects of object-orientated actions and point-light demonstrations

Abstract In Experiment 1, adult and child participants were instructed to imitate a video model performing a bowling action with or without a ball. Participants imitated the action with greater accuracy without a ball and in general adults were more accurate than children. In Experiment 2, adults and children were shown a video or point-light display of the bowling action. There was no difference in movement form between the adult point-light and video groups. In contrast, children were poorer at reproducing the action when viewing point-light compared with video sequences (P < 0.05). The novel point-light display hindered the childrens ability to provide conceptual mediation between the presented information and action requirements. In Experiment 3, a child point-light group was provided with perceptual-cognitive training. The perceptual-cognitive training group demonstrated better movement reproduction than a group who viewed the point-light displays with no training (P < 0.05), although there were no differences between participants who received training and those who viewed a video. Children are able to perceive and use relative motion information from a display after some general training, and the effectiveness of demonstrations needs to be judged relative to the task context.

Constant or variable practice: Recreating the especial skill effect

An especial skill occurs when performance of a single action from within a class of actions produces an advantage in performance. This advantage in a single action over others in the class is presumed to result from large amounts of practice performing the specific action (Keetch, Schmidt, Lee, & Young, 2005). In an experiment involving the learning of a basketball set shot, practice was manipulated to identify whether an especial skill effect emerges at the free-throw line as a result of constant practice conditions in novice performers. After a pretest, which involved set shots across five distances, participants were randomly assigned to one of two intervention groups. A constant practice group (n=10) performed 300 trials of the set shot at the 15 ft free throw line only, whereas a variable practice group (n=10) performed 300 trials across five distances. Shot accuracy increased for both groups as a result of practice at the 15 distance. However, on the posttest, a significant difference was reported between actual and expected scores for the constant practice group only. This finding provided evidence that an effect similar to that seen for especial skills emerges as a result of constant practice. Although an especial skill effect could result from massive amounts of practice, we show it can emerge as a result of short term repetitive practice, indicating that the type, rather than amount, of practice is important.

Demonstration as a rate enhancer to changes in coordination during early skill acquisition

Abstract We compared the nature and rate of change in intra-limb coordination in participants who observed a video model (model) with those who practised based on verbal guidance only (control). Sixteen male novices threw a ball towards a target with maximal velocity using a back-handed, reverse baseball pitch. Participants in the model group immediately changed their intra-limb relative motion to more closely resemble the models relative motion pattern. This new coordination pattern, and concomitant changes in ball speed, was maintained throughout acquisition, without further change. In contrast, the control group showed no change in coordination or ball speed across acquisition. Our findings suggest that demonstrations act as a rate enhancer, conveying an immediate movement solution that is adopted early in acquisition. A model may constrain the learner to perceive and imitate the models relative motion pattern as suggested by Scully and Newell (1985). The stability of this new movement pattern questions accounts of learning, which suggest that prescriptive, directed learning may result in the “soft assembly” of an inaccurate and temporary movement solution.

An especial skill: Support for a learned parameters hypothesis

We tested the learned parameters hypothesis as an explanation of the especial skill effect. Outcome attainment and movement kinematics were recorded for 10 expert and 10 novice players performing basketball free-throw shots at five distances (11-19 ft) with a regular and heavy weight basketball. As predicted, experts performed better than expected relative to the regression equation at the 15 ft, free-throw line with the regular basketball, supporting the especial skill effect. This effect was not present for the experts when shooting with the heavy ball. Novices did not show an advantage at the free-throw line when performing with either ball. Although the outcome attainment scores support the learned parameters hypotheses, kinematic analysis failed to identify differences in the movement pattern for the especial skill, suggesting that these skills (i.e., shooting at different distances) are not governed by separate motor programs.

Scaling a motor skill through observation and practice

The authors examined the proposal that a motor skill is scaled through physical practice and not through observation of a model. In 4 groups, participants (N = 32) did or did not imitate a model bowling a ball to a target 8 m away. In an assessment phase, those groups did or did not observe the same model bowling a ball to a target 4 m away. Participants who viewed a model in the assessment phase were more accurate and consistent in terms of bowling accuracy than were those who did not. Their shoulder and wrist velocity profiles were more similar to those of the 4-m model than were those of the no-model group. Participants who had previous practice and viewed a demonstration were more accurate at scaling the wrist of the bowling arm. Observing a demonstration facilitates the acquisition of control-related features of a movement. Furthermore, early acquisition of coordination aids the use of velocity information for scaling the endpoint of the primary effector.

Current status of observational learning research and the role of demonstrations in sport

When teaching sports skills, most coaches rely heavily on demonstrations as a method of conveying information to learners. Yet, despite widespread use, their effectiveness in facilitating the learning process has not been adequately determined. On a more positive note, as a result of recent improvements in measurement sensitivity (e.g. threedimensional motion analysis, eye gaze tracking and fMRI), and enhanced opportunities to employ novel interventions and display manipulations, the field has moved on considerably from its original roots in social learning theory. While social learning theory has been instrumental in enhancing our knowledge of the learning process, relevant questions have started to emerge that have their foundations in the area of visual perception. In this special issue, we provide an overview of research from the sports sciences, psychology, and the neurosciences. Our aim is to provide a brief taster of what is fast becoming a vibrant area of study. Altogether, eight papers are presented that highlight current and pertinent issues with respect to the nature of the observational learning process and its implications for the teaching and learning of sports skills. A mixture of review papers and empirical contributions is presented. In the first two papers, attempts to understand how processes related to action execution are involved in observational learning and imitation are discussed. The first paper by Vogt and Thomaschke provides an overview of behavioural and neurocognitive research on imitation learning. The authors conclude that the neural processes involved in observational learning are influenced by instructions and prior experience, and that there is a strong overlap between structures involved in motor execution, observation, and imitation. This latter conclusion is supported by empirical research from Bouque and colleagues, who present data showing that observation of incongruent actions during movements interferes with motor production. This interference is reported regardless of whether the observed actions were performed by a live model or presented as a two-dimensional video display, or whether the observed actions represented biological or non-biological motion. The authors conclude that the perception of action goals and not just biological motion perception interferes with action execution. The importance of action goals on the accuracy of observational learning is a recurring theme in the review by Hodges and colleagues. These authors provide an overview of experimental research focusing on the nature of the information that learners perceive during the observational learning process. Several methods are presented, typically using whole-body, sports tasks, to answer this question, including comparisons between video and point-light displays, manipulations to the amount and type of information presented in the display, analysis of visual search, and manipulations to the task context in terms of outcome goals. The authors conclude that actions are primarily constrained by information pertaining to the end-effector and that the task context, such as feedback and target attainment, significantly influences how demonstrations are employed. The role of developmental age as a mediator in observational learning is the theme for the next two articles. Ashford and colleagues present a metaanalysis involving empirical research published over the last 65 years to determine how demonstrations differentially affect child and adult populations in terms of both outcome attainment and the quality of the reproduced movement. Their analyses show that demonstrations aid children in attaining outcome goals, more so than adults, whereas adults show benefits from demonstrations in terms of the quality of movement form. The authors discuss this distinction in terms of Newell’s (1985) phases of skill development. In contrast to children who are more likely to be at the early coordination stage of learning, adults are more able to use a demonstration to refine (i.e. control) the quality of an existing action. In the following paper by Hayes and colleagues, comparisons across child and adult populations are made to determine how the task context and presentation format affect the quality of observational learning. Specifically, three experiments are Journal of Sports Sciences, March 2007; 25(5): 495 – 496