Chris Button¹, Glenn Cundaris² and Peter Lamb¹
1: Sport Scientists at the School of Physical Education, University of Otago, Dunedin, New Zealand. Contact: This e-mail address is being protected from spambots. You need JavaScript enabled to view it , This e-mail address is being protected from spambots. You need JavaScript enabled to view it
2: Golf Coach, Cundari School of Golf, Northern Ontario, Canada. Contact: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

Introduction

Golf is a global sport and therefore it presents significant commercial opportunities. Not surprisingly, assistive devices that purportedly enhance performance saturate the golf equipment market. Many companies claim their products can improve various aspects of play using anecdotal evidence (or “pseudoscience”) to add legitimacy to their selling pitch. Recently, the first author (a sport scientist) was contacted by a golf coach (second author) to provide an impartial opinion on one such existing device (Explanar™, www.explanar.com). The Explanar™ system is an adjustable aluminium hoop upon which the golfer can position the club shaft to maintain a consistent plane of motion throughout practice swings (see Figure 1). To our knowledge there are no objective, independent evaluations of Explanar published in the sports science literature. In the apparent absence of trustworthy research is there any way to be certain that such a product is an effective training tool?

The aim of this article is to stimulate further discussion and reflection amongst scientists and practitioners with regards the benefits of assistive devices. We decided that rather than focusing solely upon the merits of Explanar™, a general commentary about assistive devices in golf would be of more value to the Coaches Information Website. None of the authors have any financial conflicts of interest or affiliations to sports equipment companies.

Merits of Assistive Devices

For many learners, especially beginners, the golf swing is a complex, unfamiliar movement. This provides a challenge to the coach or teacher who may have been immersed in the sport for most of their life. It can be hard to remember what it felt like to be a beginner. In this respect a teaching device like The Explanar™ can be useful for developing a 'ball park' movement through extrinsic feedback, that is not verbal. Providing extrinsic feedback has been shown to facilitate the initial learning of unfamiliar movements (Button & Pepping, May 14, 2002; Masters, Maxwell, & Eves, 2009). Providing such feedback to a learner means the coach can avoid the common dilemma of finding the words to explain what the learner should do. Extrinsic feedback allows the learner to narrow their search during practice for a useful movement.

Figure 1. Picture of a learner practicing with Explanar™

In a similar manner, an assistive device may be useful for focusing the learner's attention to a concept the coach has introduced. In this sense the device may complement the coach's instructions or vice versa. This may allow the learner to practice a specific part of the swing, while still going through the full range of motion, but leave the rest of the movement relatively undisturbed (Perkins-Ceccato, Passmore, & Lee, 2003).

For example, the practice strategy of using elastic exercise bands tied between body parts and/or the club is often used to direct attention to a specific element of the swing.

Another merit of assistive devices may lye behind a simple placebo effect (we won't talk about ethical issues of prescribing placebos). Golf is a passion for many people and many will do just about anything to improve. Often just expecting to play better can give them confidence and allow them to realise their current potential. This temporary increase in confidence could come from a tip from a friend, a new club, from a new fitness regime or from a training device like The Explanar™.

Biomechanically, the Explanar™ addresses one specific swing fault -- incorrect swing plane. To define what a correct swing plane is would go beyond the scope of this article as we would have to treat the swing plane of the golf club as a three-dimensional trajectory and consider whether that 'plane' should be invariant from shot to shot and for different learners (Coleman & Anderson, 2007). For the purpose of this article, we consider an effective swing path to be:

The elliptical trajectory of the club so that, at the event of impact, the club face is oriented in a way that the
tangential velocity of the ball coming off the club face would be along the intended target line.

Repeatedly constraining the path of the club by fixing the shaft of the club to the device during the swing may reduce the variability of the swing path. The likelihood of this happening of course depends on the amount of variability in the learner's swing path to begin with. The more variable the swing path, the more potential the device has to reduce variability.

Reducing variability in swing path is one goal of many golfers but the device potentially offers another, more immediate, performance benefit, i.e., by improving the impact condition. If the adjusted swing path promotes a square club head upon ball contact, the potential to hit the ball long and straight is increased.

In summary assistive devices can be helpful because they:

• Provide direction: To many learners the golf swing is a complex, unfamiliar movement – assistive devices may help them to quickly develop an apt ‘ball park’ movement solution through added (extrinsic) feedback.
• Add feedback: Providing extrinsic feedback has been shown to facilitate the initial learning of unfamiliar movement patterns.
• Can correct faults: Useful for players with obvious swing plane ‘faults’ that play a major role in shot inconsistency.
• Focus attention: Assistive devices or aids may help draw the learner’s attention to a particular technical issue (e.g., length of backswing) without disrupting the rest of the movement pattern.
• Increase confidence: Some aids make the movement pattern easier to repeat thereby creating confidence in the learner’s ability to perform a given skill.
• Are easy to use: The devices are usually somewhat mobile and can be brought into different practice environments.
• Effect performance: Often result in rapid and quality performance improvements in terms of more effective ball flight (based on second author’s experience).

Against Assistive Devices

Acting upon external feedback may not always facilitate learning and the developmental level of the learner as well as the way they are using the feedback need to be carefully considered. For example, by practicing with external feedback, such as that of the device, the learner's ability to develop based on their own intrinsic feedback (i.e. movement proprioception, the sound of contact) is diminished. The learner may become dependent on practicing with external feedback (Verschueren, Swinnen, Dom, & DeWeerdt, 1997). The 'feel' of the shot can also be altered by using a device that constrains or limits the movement.

Such devices also risk reducing the cognitive effort put into practicing. If the learner only has to move his/her club along the path of the device there may be less demand on relating their movements to the outcome nor will they have the awareness to consider game strategy. Decreasing cognitive load beyond a certain threshold tends to inhibit the transfer of skill learning (Ericsson, 2001).

A limitation of this discussion, as mentioned above, is that we do not consider the applicability of one specific movement from individual to individual. What may work for one person may not work for another person. In fact, evidence suggests that there is a great deal of variability between individuals for a number of different types of movements (Button, Davids, & Schöllhorn, 2006; Chow, Davids, Button, & Rein, 2008).

On the theme of variability, a hot issue among movement scientists lately, is variability within a practice session. For golfers, the repertoire of shots needed in an average round of golf is so large that there is not enough time to practice each shot they may face. Rather they need to develop the ability to adapt their swing to different conditions they may experience during play. This requires the learner to vary the lie, turf, club, trajectory, etc. during practice (Knight, 2004) - not a strength of The Explanar™.

In summary assistive devices can be harmful because they:

• De-emphasise internal feedback: The learner is not encouraged to develop their own intrinsic feedback if they become reliant on practicing with external feedback. The end result may be low transferability to the golf course.
• Alter feedback: Typically, the "feel" of the movement is not the same as without the aid.
• Often result in practice of the skill in parts: Many aids do not respect the golf swing as a discrete skill, requiring the learner to complete only parts of the desired movement in isolation.
• Encourage mindless practice: In which a movement pattern is simply copied, i.e. - not mentally effortful. For example, aids may discourage learner from revising game strategy with each performance.
• Are not individual-specific: The feedback may be directing them to swing the club in a way that is not appropriate for them. If they can only do a skill “one way” then the chances of them adjusting during growth periods or developmental periods is limited
• Do not emphasise playing environment: Rarely take into account important environmental variables (such as rough, uneven lies, wind direction, etc.) and assistive devices do not emphasize how the golfer should become sensitive to or adapt to these factors
• Temporary confidence: Whilst initially motivating, the aid may also create an environment of low self-esteem in the learner - “I could do it with the aid, why can’t I do it know? What’s wrong with me?”
• Repetition of same pattern: Perfect practice does not make perfect; it creates a narrow, restrictive bandwidth of movement patterns for an athlete to perform with.
• Are expense: Expensive way to possibly improve your handicap!

Hypothetical Case Studies

To determine whether using a training device will be useful or not there are many things to consider:

1. Will using the device be beneficial to the learner based on how developed their movement pattern is?
2. Whether the nature of the learner's swing faults lend themselves an intervention with the training device?
3. Within a practice session, how should the device be used?
4. Long term, how should the device be used?

To help coaches with these considerations, we think the best approach is to provide a few hypothetical case studies where the device would be useful.

Case Study 1

Brad has been playing golf for more than three years and recently has been playing frequently (twice a week). He can break 100 at his home course but usually doesn’t. His weaknesses are a slice that is predictable in the sense that every shot will curve from left to right (he is right handed) but unpredictable in the sense that one shot may curve drastically more than the next. He also has a difficult time playing when the wind is strong as a head wind or a left to right wind exaggerates the slice to point where it is almost unplayable and a right to left wind robs him of his distance off the tee and distance control into the green.
It would appear that variability of club head trajectory is not Brad’s main problem. He can usually hit the ball with approximately similar impact conditions, his problems come in the large effect of his mis-hits, or mis-swings. An error on the side of more spin and higher trajectory for long shots is more costly in golf than the opposite. This ‘swing fault’ is also dangerous because to reduce the erratic tendencies of this player, adjustments need to be made which would intuitively go against his knowledge of the golf swing. For example, he thinks to himself, when he doesn’t want the ball to go to the right he must adjust his club head trajectory to travel slightly more to the left of the target line and rotate the club head around the long axis of the shaft more quickly. Of course by doing this his slice has been exaggerated and he attributes the bad shot to a bad swing rather than a misunderstanding of the golf swing.

In this example a consistent swing fault appears to limit the player’s performance. Using a swing plane tool on this golfer may potentially improve his swing kinematics and his understanding of the relation between many swing parameters (club head speed, angle of descent, face rotation, etc.). However for many of the reasons discussed above, use of the assistive device should be carefully introduced and phased out over practice to enable Brad to make the required alterations to his swing without creating dependence on the device.

Case Study 2

Stan is a very good golfer. He has a strange swing but makes it work. His strange backswing and downswing path is something he is not even aware of while he is doing it but does acknowledge that his peers consider his swing unconventional. Stan's teacher does not attempt to change this unique swing path but some of Stan's friends suggest he try tweaking it a bit. One suggests The Explanar™ device. Stan is unsure if it's a wise idea to mess with something that works. The dilemma here is that Stan, although he plays well now, doesn't know how he will play if he were to change his swing. Just because something is conventional doesn't mean it's right, right?

If Stan were to try the device it’s unlikely he would be in danger of 'losing' his swing. His general movement pattern is developed enough to be robust to temporary changes caused by trying out the device. Consider Stan on the range practising sidehill lies, will that wreck his natural swing? It is a different movement pattern. In fact it helps him adjust his swing to different conditions, which is actually the key to golf (and many other sports for that matter). So back to the device, it would not likely change Stan's swing plane unless he wanted it to change his swing plane. If anything it may help him explore a new movement pattern and contribute to his ability to manipulate his swing and still achieve the desired outcome.

Case Study 3

Beetle is a very average/mid-handicap 40 year-old who has been playing with scores between 88 – 102 for over 20 years. According to Beetle controlling the direction of the ball flight has been his biggest concern. His Saturday morning playing partners have regularly told him his alignment is the reason his ball flies crooked – he aims very much to the right (RH golfer). When he adjusts his alignment his ball position feels uncomfortable and he has difficulty trusting it.

After watching PGA Tour golf on television and seeing how they practice (as well as reading Golf Digest regularly) he has built a “T” shaped aid to assist in his ball position and aim. As per the golf culture, he hits thousands of balls on the driving range with his new found aid only to hear his buddies tell him his aim is still “no good” when he steps on the tee on the golf course. Beetle is now very frustrated as he feels that he is aligning well on the driving range and doing all the right things.

Typically the practice in this scenario has been very blocked and not random and clearly Beetle has only learned the skill of aligning of his feet and body to the “T” and not the skill of aligning his feet and body to the target. The current golf culture, the PGA Tour “best practice” and Golf Channel belief system has been hit many balls with the use of an alignment aids.

Summary

In summary, the value of assistive devices depends on the specific learning issue that is presented. In Case 1 above (Brad) the device is used to address a specific fault in his swing, the advantage of using the device in Case 1 is that it complements the verbal instruction given by the coach -- just one example of how such a device may be beneficial. In Case 2, the player has reached a performance plateau. Since his movement pattern is deeply rooted the device helps him 'break the mould' and experiment with new movements. In Case 3, the player experiences limited transfer between practice with the device and performance on the golf course. When evaluating training devices like The Explanar™, you have to be able to identify possible benefits of the device, characteristics of the learner that influence the device's benefit and if you decide to use a training device a plan on exactly how to use it, short-term and long-term, needs to be decided on.

References

Button, C., Davids, K., & Schöllhorn, W. (2006). Co-ordination Profiling of Movement Systems. In K. Davids, S. Bennett & K. M. Newell (Eds.), Movement System Variability (pp. 133-152). Champaign, Illinois: Human Kinetics.

Button, C., & Pepping, G. J. (May 14, 2002). Enhancing skill acquisition in golf: Some key principles., from http://www.coachesinfo.com

Chow, J. Y., Davids, K., Button, C., & Rein, R. (2008). Dynamics of movement patterning in learning a discrete multiarticular action. Motor Control, 12, 219-240.

Coleman, S., & Anderson, D. (2007). An examination of the planar nature of the golf club motion in the swings of experienced players (Vol. 25, pp. 739-748).Ericsson, K. A. (2001). The path to expert golf perferformance: Insights from the masters on how to improve performance by deliberate practice. In P. R. Thomas (Ed.), Optimising performance in golf (pp. 1-57). Brisbane, Australia: Australian Academic Press.
Knight, C. A. (2004). Neuromotor issues in the learning and control of golf skill. Research Quarterly for Exercise and Sport, 75(1), 9-15.

Masters, R. S. W., Maxwell, J. P., & Eves, F. F. (2009). Marginally perceptible outcome feedback, motor learning and implicit processes. Consciousness and Cognition, 18(3), 639-645.

Perkins-Ceccato, N., Passmore, S. R., & Lee, T. D. (2003). Effects of attention depend on golfers' skills. Journal of Sports Sciences, 21, 593-600.

Verschueren, S. M. P., Swinnen, S. P., Dom, R., & DeWeerdt, W. (1997). Interlimb coordination in patients with Parkinson's disease: Motor learning deficits and the importance of augmented information feedback. Experimental Brain Research, 113, 497-508.