Skip to content
narrow screen wide screen auto screen Increase font size Decrease font size Default font size

CoachesInfo.com - information and education for coaches

Secure login          
Enhancing Skill Acquisition in Golf - Some Key Principles
Chris Button   
  1. Introduction
  2. What is Good Movement Co-ordination?
  3. Exploration in Golf
  4. Using Movement-Related Feedback Effectively
  5. Improving Practice Structure
  6. Suggestions for Enhancing Independent Learning Behaviours

1. Introduction

Despite a wealth of scientific information in the motor learning literature about how to enhance skill acquisition, coaches are often relatively unaware of the practical implications of this work. Here, we provide information underpinned by recent research that will be of benefit to both coaches and learners of golf. If you haven't time to read the whole article you might want to scroll down to section 6 where we summarise the main conclusions for coaches and players. However we hope that you will be interested enough to dip into earlier sections and find out how we've reached these conclusions. We start by considering the very important issue of what factors contribute to good movement co-ordination in golf (section 2). An awareness of these factors will allow the reader to gain a better understanding of why the perfect swing can be so difficult to achieve. A significant amount of practice time in golf involves perceptual and/or motor exploration of one form or another. The value of exploratory behaviour such as the 'practice swing' will be explained, alongside some suggestions for enhancing search (section 3). After having explained the important factors contributing to co-ordination, in the following sections we discuss what can be done to help golfers improve their co-ordination. We comment on how the learner can use movement-related feedback (such as video playback and suggestions from a coach) most effectively (section 4). For example, questions such as how often should feedback be used during practice, and what type of feedback is most effective, will be considered. Then we comment on how practice structure can influence learning style and ultimately the retention and transferability of golf skills (section 5). Finally, we will summarise with a list of practical recommendations that may be used by coaches and learners alike in order to maximise the time spent in teaching and learning golf techniques (section 6).

2. What is Good Movement Co-ordination?

In this section, we describe how golf coaches and players can improve their understanding of movement co-ordination. This concept will help readers to answer questions such as what should I be looking for (or expecting) when watching a player swing a club? And, how do learners typically change their co-ordination as they practice?

What makes elite golfers such as Tiger Woods, Sergio Garcia and Annika Sorenstam so effective? The answer is in how they co-ordinate their limbs and ultimately the golf club in relation to the ball. Movement co-ordination can be defined as "the patterning of body and limb motions relative to the patterning of environmental objects and events" (Turvey, 1990). In other words, co-ordination involves establishing a close relationship between the way our limbs move and the specific environmental circumstances in which we perform. For example, a golfer must produce precise, sequential movements of his/her body in order to translate the club head towards the ball in a way that is appropriate to the lye of the ball, the distance from the hole, the environmental conditions and also any obstacles ahead. Therefore, in order to achieve good co-ordination, a range of different movement patterns are required throughout a typical round of golf in order to deal with the unique situation demanded by each shot. Importantly, this view is contrary to a commonly held misconception that good golfers are simply reproducing the same shot (or 'motor programme') again and again. Furthermore as each person is different in terms of factors such as their anatomical build, strength and flexibility, the ideal co-ordination patterns for one person may be very different to what works well for you!

So how is it possible to measure or assess co-ordination as expressed in these terms? One requirement is to observe and understand how mechanical 'degrees of freedom' are used by the golfer. 'Degrees of Freedom' can be explained as the number of ways in which limbs can move and joints can rotate. A golfer has many degrees of freedom throughout his or her body - for example, the arm has several joints, each of which can move in various directions (Latash, 1996).

Learning a skill often involves changing the number of degrees of freedom that are active in a movement pattern (Button et al., 2003). For example, a novice in the early stages of learning to swing a club is not yet able to co-ordinate all the degrees of freedom at their disposal. Their early attempts at striking the ball may involve a simple rotation of the arms with the wrists and elbows locked, no twisting of the knees, and little trunk rotation. By tensing muscles across several joints in this fashion, the act of swinging the club seems inefficient and jerky. Gradually, as a function of practice, the learner starts to relax some of these muscles at the right time, aiding the rotation of the trunk, flexion and extension of the right elbow, and allowing the wrists to hyperextend and flex with effective timing to accelerate the club more efficiently. In the video clips below you can observe some of these characteristics by comparing a novice's swing to that of a more experienced player.

Novice

JavaScript is disabled!
To display this content, you need a JavaScript capable browser.

Elite

JavaScript is disabled!
To display this content, you need a JavaScript capable browser.

So learning a golf swing is characterised in general by an increase in the use (exploitation) of available degrees of freedom. By increasing joint ranges of motion the player should be able to generate more angular rotation of the club and hence strike the ball further. Conversely, whilst putting, learners need to appreciate the importance of reducing active degrees of freedom in their upper body so that the trunk, elbows and wrists remain passive whilst the shoulders rotate the club in a pendulum-like action (Sanders, 2001). This strategy ensures that the club is translated in a smooth path with the appropriate direction throughout the putt. Many golfers will identify with the experience of hitting poor shots whilst trying 'too hard' or when placed under pressure. In the majority of cases these problems are caused (often without the golfer being aware of it!) by an unintended change in the degrees of freedom they have used.

In fact using the right degrees of freedom is only half the problem! Good co-ordination also involves varying technique to fit with each specific situation a golfer finds themselves in. Unlike practice on a driving range, environmental and task conditions change dramatically during a round. By 'environmental and task conditions', we refer not only to general factors such as the light, wind direction, and ambient temperature, but also to specific variables such as the surface from which the ball is to be played, any hazards that lie between the ball and the hole, and the specific club (i.e. driver, wood, iron or putter) that is chosen. For example, subtle differences in the pitch shot are required when playing from on the fairway compared to playing out of heavy rough, or when playing over a nearby tree. Similarly, when playing a crucial putt on the green, the distance the ball sits from the hole, the speed of the green surface, and the nature of any slopes or undulations, are all vital factors that should be taken into account (Pelz, 2000; Koslow and Wenos, 1998). Furthermore, the physical characteristics of a 9-iron are significantly different than those of a driver, a wood or a putter, requiring subtle differences in the way they are being handled.

Given such a range of variables to deal with it is a wonder that players can achieve good co-ordination at all! How can highly functional adaptations to movement patterns such as a golf swing or putt under ever changing environmental and task conditions be explained? Research suggests that performers subconsciously detect information about important variables (like the lye of the ball, distance from hole, sweet spot of club, etc.) and use this to adapt their movement patterns in a highly, sensitive and continuous fashion (Carello, et al., 1999; Craig et al., 2000). What this highlights is that the perceptual demands of playing golf should not be underestimated.

3. Exploration in Golf

In this section we will see that exploration in particular is important for the discovery and use of the information we need to guide our actions in golf. This discussion should help the reader to understand why behaviours such as the practice swing and time spent 'reading the green' are so important to the golfer.

Golfers have continuous access to information from their sensory organs (e.g., eyes, ears, and muscles) and they use this to guide their actions. Hence, accurate detection of important information, i.e. perception, has as much to do with good co-ordination as the physical act of swinging the club. Good co-ordination requires achieving a close relationship between relevant perceptual information and the patterning of limbs (and club) to achieve the goal of the task. An important part of learning consists of the search and discovery of relevant information.

To detect the information necessary to guide a swing, exploratory movements are essential and we perform a lot of exploration without even being aware of it. For example, think about the behaviours golfers show before actually playing a putt, also called pre-performance routines (Fairweather, Button & Rae, 2002). They walk around the ball, bend behind it, walk a bit more, stoop behind the hole, take small practice swings, etc. It has become increasingly known that these activities help to direct the golfer's attention to relevant information, e.g. about the distance between the ball and the hole, the speed of the green and the amount of give or borrow to account for (dependent upon the slope of the green). As a result of these visual and also non-visual (haptic) explorations, important issues like which club to choose can be decided upon. Having chosen a club, we handle, swivel and swing it, again, actively exploring it's properties (and often simultaneously with the explorations described above). These seemingly unnecessary movements are actually examples of perceptual search and are therefore extremely important. Sometimes these activities result in us choosing another club because the collective information sources 'tell' us it is more appropriate. What should become evident is that an important part of becoming a good golfer is learning to find the information necessary for the guidance of well co-ordinated golf movements, which involves learning to perform the exploratory movements that help reveal this information.

A very important source of information is where on the golf club-head to hit the ball. In relation to the size of the golf ball, club-heads are quite large objects. So it is important to know what defines the ideal point of club-ball contact. As most coaches and players know, ball contact should not occur at simply any place on the surface of the club-head. Rather, a successful drive (or chip or putt) entails achieving contact with the ball at the club-head's "sweet spot" (or in scientific terms, its centre of percussion). When alignment of the ball with the sweet spot is achieved, contact feels right. However when this alignment is missed, not only does the ball drift off in an unintended direction, but also contact immediately sounds wrong, feels effort-full, and in extreme cases, hurts your hands! Although the sweet spot is confirmed after contact by such sensations, its usefulness in golf depends on awareness prior to contact. Therefore, the precise alignment of ball and club-head requires that the sweet spot is perceived before the actual shot is made. Experiments indicate that golfers can detect the sweet spot of a golf club non-visually simply on the basis of wielding (Carello et al., 1999). This explains why, as soon as we take a golf club in our hands we get a sudden urge to start hefting, wielding, swivelling and swinging it. These wielding movements, aimed at revealing very important information about the location of the sweet spot on the chosen golf club head are a good example of the importance of explorations before and during the execution of our swing.

As the above example shows, a lot of the information used to guide golf movements is not visual. A mixture of visual and non-visual information is used to solve one of the fundamental problems in golf, i.e. how to bring together the ball and the club-head. Early in learning, players tend to rely heavily upon visual information to help them co-ordinate their actions - (think of the inexperienced players who lift their heads early to track the ball). This isn't particularly helpful because, whereas the location of the ball can be seen for the majority of the full golf swing, the path of the club cannot actually be seen by the player. Research has now shown that although the club can be guided visually, the actual guidance of the trajectory of the club is primarily the job of the haptic perceptual system. This is why, as a function of experience, players tend to find it helpful to use the feel of their muscles ('proprioception') during a shot to fine-tune the swing appropriately. A sole reliance on visual guidance for the player would be at the expense of registering information about the ball's location and its time-to-contact with the plane of the club. In summary good golfers learn to become sensitive to haptic information and typically guide the club to the point of contact non-visually by means of haptics. Interested readers are directed towards the popular book, "The Inner Game of Golf", in which Tim Gallwey (1986) suggests some simple strategies during practice that can help players to improve their sensitivity to haptic information.

In this section we have explained that learners have continuous access to information from their own sensory organs (e.g., eyes, ears, muscles) that help them to guide their actions. Better players learn to become sensitive to relevant information as a function of the practice that they have undertaken. Good co-ordination requires the golfer to link perception and action to achieve the goal of the task, i.e. completing a round in as few shots as possible. This is no simple task given the vast number of degrees of freedom available to the golfer and the multitude of different perceptual challenges that they must face. However the issues described in this section are also part of what makes the game so popular. It is little wonder why many golfers find consistency the hardest part of the sport to achieve. So can anything be done to help the golfer towards better co-ordination? In the following sections, we discuss how this can be achieved.

4. Using Movement-Related Feedback Effectively

In this section, the issue of how to deliver feedback effectively to the learner is considered. This should help readers to know what types of feedback are helpful to the learner and when is the best time to supply that information during practice.

One of the most difficult problems that inexperienced players face is that they are not be able to understand or pay attention to all of the sources of information that guide their movements. Therefore, early learners typically benefit from augmented (added) feedback whilst they are searching for the best way to swing a club. For example, occasional information from the coach about body position during the golf swing can accelerate the rate of learning this skill. In this section, we describe how augmented feedback should be administered to enhance learning in golf.

A common strategy of learners is to try and copy or mimic the technique of more able players during practice - remember the recent advertising slogan featuring children saying, "I'm Tiger Woods"? Furthermore, coaches often provide information about technique to learners with a blueprint of the 'perfect swing' in their mind. However, as we discussed in section 2 on co-ordination, no one perfect swing exists. For each individual and situation that they might find themselves in, a variety of adaptations to the swing can still produce the desired outcome. As we shall describe in this section this concept has serious implications for the coach in terms of how they should generate and supply feedback during practice. The issue of how movement related feedback can be used to improve skill acquisition has received much attention in the motor learning literature (for a review, see Magill, 2001). Indeed much consideration has been paid to questions like: how detailed should the feedback be? How often should feedback be given to the player by the coach? And when is the best time to provide feedback?

One type of visual feedback that is becoming increasingly popular in a variety of sports, and particularly golf, is video recordings, taken whilst the learner practices. This strategy was examined in a research experiment conducted by Janelle et al. (1997). The task of precision ball-throwing with the non-dominant limb was chosen to address whether video feedback was effective during acquisition of a novel task. 3 groups of learners received movement related information. One of the groups watched video of their technique after every 5 trials (SUMMARY). It was also suggested that learners would benefit most from choosing the schedule of video provision. Therefore, the other two groups consisted of a group that chose when feedback was given (SELF) and a group who had no choice but had a matched feedback schedule to the SELF group (YOKED). Each subject was filmed performing the acquisition trials and had access to outcome information as they saw where on the target the ball landed.

Figure One

Figure 1: Form ratings of throwing technique for each learning group (higher scores indicate better performance).
Reprinted with permission from Research Quarterly for Exercise and Sport, Vol.68, No. 4, pp. 269-279, Copyright (1997) by the American Alliance for Health, Physical Education, Recreation and Dance, 1900 Association Drive, Reston, VA 20191.

The form scores from Janelle et al's (1997) study lend clear support to the use of video feedback for learners, see Figure 1 above. A KR group, who received no video feedback and solely outcome-related information, consistently showed worse technique according to impartial judges than the 3 video groups (accuracy scores were also lowest in the KR group!). During skill acquisition trials, the SUMMARY and SELF groups performed as well as each other, however in retention trials without feedback, the better form scores came from the SELF group. Finally, the YOKED group appeared to have suffered from not being given the independence to choose when feedback was administered. Despite watching the same amount of video at the same times as the SELF group (only on 11% of trials), the retention of the YOKED group was not as good.

How can such research findings be interpreted by golf coaches and players? First, it seems important to allow the learner some control in terms of when movement-related feedback is supplied. It is likely that self-regulation of feedback enhances motivation and also leads to more effective learning strategies. It is a common misconception that learners should be provided with as much feedback from a coach as possible in order to 'perfect' their technique. In fact the research described above clearly demonstrates that the learner benefits most from a modest provision of movement related feedback that is related to only the most relevant aspects of the skill. Given each individual learner's own physical and mental characteristics the 'best' way for us each to move is slightly different (Sanders, 2001). Therefore it makes little sense for us all to try to swing our driver exactly like an elite player does. Instead feedback should be used to help direct the learner to improve the general mechanical principles of a movement pattern, such as generating angular momentum with a long, smooth back-swing (for other examples, see Carr, 1997).

One of the reasons why supplying too much feedback frequently can interfere with motor learning is that the learner is encouraged to engage in self-talk during the production of the swing (Fairweather and Sidaway, 1994). The potentially damaging consequence of such critical thinking may be that the learner's attention is repetitively drawn away from achieving the task goal itself. Wulf and colleagues (Wulf, Lauterbach and Toole 1999) claim that attentional focus is more productive when directed towards the (external) effects that the learner's movements have rather than producing the movement itself (internal). For example, these researchers asked two groups of learner golfers to practice a pitch shot to a target 15m away. An internal-focus group was asked to pay attention to the arm swing and adopting the 'correct' positions throughout the stroke. The attention of the external-focus group was directed towards the club swing, specifically to let the club perform a pendulum motion. The results as shown in Figure 2 clearly indicate the better performance of the external focus group in terms of pitching accuracy. Furthermore the advantage persisted, although to a lesser degree, in a retention test performed 1 day after practice. In a related study Maxwell et al. (2000) also argue against the use of excessive verbal instruction during golf-putting as learners found the information unnecessary and it actually hampered performance under stressful conditions (i.e., competition).

Figure two

Figure 2 : Accuracy scores of internal- and external-focus groups in practice and retention (higher scores indicate better pitching accuracy).
Reprinted with permission from Research Quarterly for Exercise and Sport, Vol. 70, No. 2, pp. 120-126, Copyright (1999) by the American Alliance for Health, Physical Education, Recreation and Dance, 1900 Association Drive, Reston, VA 20191.

In summary, a considered use of movement-related feedback is necessary to produce optimal learning in golf. The coach should provide small amounts of information (e.g. video, instructions) that are directed towards improving the general mechanical principles of a shot or encouraging exploration, rather than reproducing someone else's technique. In the next section we consider how feedback may be provided within a practice structure that emphasises independent learning.

5. Improving Practice Structure

Finally, in this section we shall help readers to understand the importance of structuring practice effectively. For example, you might have wondered how often should a player practice with a certain type of club? And why certain players cannot reproduce a consistent swing on the driving range in an actual match? Read on ...

As suggested in section 2, motor learning is best described as a search for task solutions and practice is the learner's opportunity to explore these solutions (Newell, 1996). Therefore learning and practice behaviours are closely linked. Consider how players typically practice for golf. Practice may involve spending an hour or so at the driving range after work and perhaps a few putts on the practice greens prior to a round. Now think of how your practice behaviour differs compared to what you might actually do during a competitive match. Players rarely practice the full range of skills that are required during a golf match, such as chipping from an awkward lie in a bunker or coping with anxiety whilst walking to the green. Instead we tend to spend a lot of time swinging the same club, time after time, in order to hit the ball as hard and as true as possible. However, such repetitive behaviour is not typical of golf as it discourages the use of important, preparation routines that are commonly employed by players (see section on Exploration; and also Fairweather, Button & Rae, 2002). So what factors should be incorporated into golf practice to gain maximum benefit for performance?

The first suggestion we propose is to introduce more variety into practice. Research has indicated that variable practice conditions are shown to be preferable to constant practice in terms of promoting long-term learning (Magill, 2001). Therefore in practice, most players would benefit from more active exploration - which can be achieved in many ways! For example, whilst practising drives the learner could experiment with different lengths of back swing and follow-through. Another option might be to change the speed of the swing. When working on approach shots, try to practice off different surfaces (e.g., short and heavy grass, shallow and steep gradients) so that the ball does not always have the perfect lye. By exploring such options (see also section 3 on Exploration), the learner should become comfortable with adjusting key control variables for the action. As subtle variations of these control variables are explored the player can start to identify for themselves the best way to swing the club during an actual match. Such simple techniques also allow the learner to develop sensitivity to the all-important sensory feedback sources that were discussed in previous sections. A large body of research suggests that motor skills practised using the variability of practice principle are retained better by the learner and can be adapted to different situations more effectively (Lee, Chamberlin and Hodges, 2001).

Likewise, the ordering of practice tasks appears to have a significant affect on skill acquisition. It has been suggested that randomising the order in which different components within a sport are practised (termed 'contextual interference') causes a slower rate of learning but improved retention of the different skills. For golf, high contextual interference could be induced by randomising the types of clubs or shots practised on a driving range. The player must then adapt their swing consistently to cope with the continual changes in inertial characteristics of each club. Once more, one might suggest that a more active and reflective style of learning would be encouraged under these practice conditions. Interestingly, contextual interference practice benefits have been found in a wide range of sports such as baseball, kayaking, and rifle-shooting (Schmidt and Lee, 1999).

A final consideration in improving the relationship between practice behaviours and game-related play would be to consider some of the psychological and physiological factors of golf that are often missing from practice. For example, a player must learn to play under varying levels of pressure / anxiety during a typical round. Therefore in practice, learners could set themselves performance goals such as pitching to within 10 metres of a target to help induce a competitive edge. Another strategy would be to alternate shots with a playing partner to get used to hitting the ball whilst others are watching. Using and practising psychological techniques such as imagery and directing attention can also help players to avoid distraction at key moments during a round (Loze, Collins and Shaw, 1999). In terms of physiological factors, throughout an average round of golf a player may walk several miles. Therefore local muscular fatigue can influence a player's technique over the last 9 holes if they have not prepared for the physical requirements of the sport. One of the key fitness components for golf has been identified as mobility. This is primarily because of the benefit gained from storing and releasing elastic energy from muscle groups in explosive actions like the golf swing. Hence, exercise and flexibility programs focussing specifically on the forearms, shoulders, trunk, pelvic girdle, and legs will help players to improve mobility for golf (Bloomfield and Wilson, 1999).

6. Suggestions for Enhancing Independent Learning Behaviours

  • Try to develop good co-ordination in golf which involves achieving a close relationship between relevant perceptual information and the patterning of limb (and club) movements.
  • Learners should be encouraged to actively search for the best techniques for them as individuals rather than to copy someone else.
  • Exploration in golf is a critical part of establishing good co-ordination. Players should be encouraged to use exploratory behaviours, such as wielding, to discover relevant information sources prior to each shot.
  • Only give instructions that are used to direct the learner to information that could be used to achieve the task more successfully (over-instruction discourages independent exploration!).
  • Do not provide feedback detailing how to perform a certain technique when information is available to alert the learner to task goal attainment.
  • Don't just assume more practice will make for a perfect player, the quality of practice structure is just as important.
  • By varying practice tasks and randomising the order in which they are practised, retention and transfer of these skills is improved.
  • Make practice more game-like so that the maximum benefit can be gained in terms of improving psychological and physical characteristics of performance.

References

Bloomfield, J., and Wilson, G. (1999). Flexibility in sport. In: B. Elliott (Ed.) Training in Sport: Applying Sport Science. Chichester, UK: John Wiley & Sons (pp. 239-283).
Button, C., Macloed, M., Sanders, R., and Coleman, S. (2003). Examining movement variability in the basketball free-throw action at different skill levels. Research Quarterly for Exercise and Sport, In Press.
Carello, C., Thuot, S., Andersen, K. L., and Turvey, M. T. (1999). Perceiving the sweet spot. Perception, 28, pp. 1128-1141.
Carr, G. (1997). Mechanics of Sport: A Practitioner's Guide. Champaign, Illinois: Human Kinetics.
Craig, C., Delay, D., Grealy, M. A., and Lee, D. N. (2000). Guiding the swing in golf putting. Nature, 405, pp. 295-296.
Fairweather, M.M., Button, C., and Rae, I. (2002). A critical examination of motor control and transfer issues in putting. Communication to the World Scientific Congress of Golf, St. Andrews, Scotland, July 23-27.
Fairweather, M. M., & Sidaway, B. (1994). Hemispheric teaching strategies in the acquisition and retention of a motor skill. Research Quarterly for Exercise and Sport, 65, 40-47.
Gallwey, T. (1986). The Inner Game of Golf. New York: Bantam Books.
Janelle, C.M., Barba, D.A., Frehlich, S.G., Tennant, K., & Cauraugh, J.H. (1997). Maximising performance feedback effectiveness through videotape replay and a self-controlled learning environment. Research Quarterly for Exercise and Sport, 68:4, 269-279.
Koslow, R., and Wenos, D. (1998). Realistic expectations on the putting green: Within and between days trueness of roll. Perceptual and Motor Skills, 87, pp. 1441-1442.
Latash, M. (1996). The Bernstein Problem. How Does the Central Nervous System Make Its Choices. In: Latash, M. & Turvey, M. (Eds). Dexterity and its Development Mahwah, New Jersey. LEA Publishers. Pp. 277-303.
Lee, T.D., Chamberlin, C.J., Hodges, N.J. (2001). Practice. In: B.Singer, H.Hausenblas & C.Jannelle (Eds.), Handbook of Sport Psychology, 2nd Edition. N.Y.: John Wiley & Sons. pp. 115-143.
Loze GM, Collins D, Shaw JC. (1999). EEG alpha rhythm, intention and oculomotor control. International Journal of Psychophysiology. 33(2): 163-7.
Magill, R.A. (2001). Feedback effects. In: B.Singer, H.Hausenblas & C.Jannelle (Eds.), Handbook of Sport Psychology, 2nd Edition. N.Y.: John Wiley & Sons.
Maxwell, J. P., Masters, R. S. W., and Eves, F. F. (2000). From novice to no know-how: A longitudinal study of implicit motor learning. Journal of Sports Sciences, 18, pp. 111-120.
Newell, K.M. (1996). Change in movement and skill: Learning, Retention, and Transfer. In: Latash, M. & Turvey, M. (Eds). Dexterity and its Development Mahwah, New Jersey. LEA Publishers. pp. 277-303.
Pelz, D. (2000). Dave Pelz's putting bible. New York: Random House Publishers.
Sanders, R. (2001). Seeking Nicklaus-Like Consistency in Putting: An Experiment for the BBC. ISBS Coaches Information Web Site, http://www.sportscoach-sci.com
Schmidt, R.A. & Lee, T.D. (1999). Motor Control and Learning: A Behavioral Emphasis, 3rd Edition. Champaign, Il: Human Kinetics Publishers.
Turvey, M. T. (1990). Coordination. American Psychologist, 45, 938-953.
Wulf, G., Lauterbach, B. & Toole, T. (1999). The learning advantages of an external focus of attention in golf. Research Quarterly for Exercise and Sport, 70:2, 120-126.