Friday, March 21, 2014

The Study - Differential versus Calibrational

When I was working in Austria, I was lucky enough to have an endless supply of fresh beginner golfers with no preconceived ideas of how the game should be played. This was a great chance for me to not only teach them golf, but do some research into how best to improve a skillSKILL set.

The goal for these golfers was simple – I had to get them around a golf course in a defined number of shots so that they could earn their ‘Platzreiferkurs’ – a certificate which allowed them to play on the course. So, I decided to focus on the main skills which a beginner should focus on. My first study involved improving the player’s ability to hit the middle of the face; a vital skill for quality play.

Beginner golfers


Each participant was given a one hour lesson where they were shown grip, stance, posture and ball position in basic. Much of this instruction was a simple ‘copy me’ approach, where I asked questions to the students to direct their awareness, such as “where is my ball in relation to my feet”?  

After they had a basic idea of the swing, each participant was educated on the fact that, for optimal distance and control, the ball should be struck from the sweet spot, which equates (roughly) to the middle of the clubface. We then did a 20 ball test (PRE) to see how many times they could strike a spot the size of a 1 euro coin drawn on the centre of the face.

24 golfers were then split into 2 groups, with average abilities matched; Calibration (CAL) N=8, Differential (DIFF) N=8, and Combination (COMB) N=8.

The calibration group were asked to hit shots and try to hit the 1 Euro size circle as often as possible. The Differential group has a line drawn down the middle of the clubface and were asked to hit 5 shots from the toe side, followed by 5 shots from the heel side. The Combination group did a mixture of both practices, starting with the differential practice and finishing with calibration. Participants did this practice for 3 x 1 hour sessions during the week.

After the first hour, a second 20 ball test was conducted (POST). Then, at the end of the week a final 20 ball test was completed (FINAL). The test parameters were the same for all groups - Hit the centre of the face in a 1 euro size circle.

CALI group tried to hit this size spot over and over

DIFF group tried to hit 5 shots from the toe side, followed by 5 shots from the heel side


Below is a table showing the results of the study


So the calibration group improved by 10% after one hour (the most improved group after 1 hour), and by 16% after a week. Differential practice group improved the lowest amount after 1 hour (4%), but leapt ahead of the calibration group by the end of the week by improving 24%. The Combination group showed an improvement of 8% after one hour, and a massive 30% by the end of the week. They were almost hitting half of their shots flush, which is quite an achievement for a beginner.


All improved

The first point to note is that all golfers improved. This is obvious, and I would have been doing a very poor job if they hadn’t gone from complete beginner to ‘better golfer’ in the space of a week. Even over the course of an hour, every group improved. This is simply down to the nature of learning – people generally get better at things the more they practice them, especially as a beginner. But it is also an important point to note. Lots of people can claim that their method improves golfers, but is it the actual method which is working, or is it the fact that someone is simply practicing more.

There could also be elements of Hawthorne effect, or certainly Placebo effect being involved. For this reason, it would be good to compare the groups against a control group. For example, if the control group showed improvements above and beyond another group (or all of them), it could be concluded that, although there was an improvement, the intervention was actually more detrimental than no coaching at all. Unfortunately, collecting data on strike pattern without the control group being aware of what was going on was difficult, and so I decided to leave a control group out of it.

Short term versus long term - calibration

It is important to note that there was a difference between the short term improvements and long term improvements in performance. The calibration group was the most improved after one hour, but the least improved after a week. This can be very important information for both players and teachers. If you need short term success and maximum improvement in a short amount of time (likely intra-day), it would be best to try a calibration style of practice, where you simply hit balls with the aim of doing it correctly each time. As long as you are getting good quality feedback and are aware of the goal, it will be valuable practice.

I believe the reasons for the quicker rate of performance improvement are an improvement in confidence levels during the intervention, and neuromuscular priming. The Calibration group were seeking good shots, so they got to hit them more often. This builds a good feeling and gives the person a (false) sense that maximal learning is occurring. Also, as the player was trying to undertake one single task (hit the middle), they were sending the same unconfused signal to the brain and body. A less variable signal resulted in slightly better performance in the short term.

There is a dark side to this, which most people don’t understand about human psychology. If you perform too well, this increases EXPECTATIONS. I noticed that the majority of CAL group participants arrived the next day with the expectation to perform as good as they did the day before, and were more disappointed and frustrated when it didn’t happen immediately, which probably resulted in their lowered overall improvement at the end of the week.

This practice provided instant gratification, but not necessarily better results.

But the message here is, if you are looking to improve your ability to hit the middle of the face before a round of golf, try simply calibrating it during the pre-round session. For teachers, to get the most improvement in performance out of your students in one single session, a calibrational approach may work best for most.


This group was interesting as they showed the least amount of improvement during the first hour, but beat the CAL group by the end of the week. This is the funny thing with learning – what happens in the short term does not always translate in the long term. There is also a difference between LEARNING AND PERFORMANCE

The Differential group finished a close second by the end of the week. So why did they under-perform during the initial 1 hour testing? From observing the students, it was clear that by asking them to hit the toe or the heel of the club during their training, even if they got it correct, the result was poor. I think most people can’t see the end goal (even if it is explained to them very clearly beforehand), and so this group didn’t understand that they were actually getting better, even though they were hitting bad shots.

The difference was, they were INTENTIONALLY trying to hit poor shots as part of their intervention. If you do something intentionally and get quality feedback, there is so much more learning occurring than if you were to hit the same poor shot unintentionally and have no feedback. For example, a shank is devastating if you didn’t mean to do it (especially if you don’t even understand that you hit it with the hosel of the club). But, if you intended to do that, it is actually improving your ability to match reality and intention, which will aid you when it comes to hitting the middle of the face. So the DIFF group went into the first hour of testing with poorer confidence, as they had spent the previous hour hitting shanks and toe shots. 

Also, there is a good chance that the confused neuromuscular signals from alternating the goal (5 toes, 5 heels) combined with no calibration work held back their improvement.

But, it is still worth mentioning that they improved. One of my beliefs for why they improved so much during the week was because

1.       They saw that this style of practice can improve them
2.       They built subconscious tools for changing where they hit on the face
3.       They had lower expectations due to the difficulty of the task

Notes for the teacher – this is probably not the best method to use if you are looking to build the confidence of a player and to get them to come back to you if it is your first time together. The post intervention testing can eliminate a lot of those problems by showing the player that they have improved at the end of the session, but by that time, the player may be feeling frustrated. It is unfortunate, as, in the longer term, this actually shows a significant amount of improvement.

For players – don’t judge your learning by your results. Just because you are hitting poor shots doesn’t mean you are not learning. In fact, you may be learning more than if you were hitting good shots. Oh the paradox!

Combi group – most improved

This group showed the second biggest improvement after one hour, and the most improvement by the end of the week. It seems that the differential practice helped to build the players’ ability to change where they hit on the face, and the calibration afterwards allowed them to manifest those new skills. I also think the order in which the intervention was conducted (differential practice first followed by calibrational) played a major role in the testing. Players went into the testing with higher levels of confidence than the DIFF group. I wonder if they would have had the same success had the order been switched?

I assume the reason why the initial testing was slightly lower than the CAL group was due to this intervention having more variation within it, causing a confusion of the nervous system during learning. However, after consolidation of this learning over time, players now had both the tools to move the strike around the face, and the confidence of the calibration period they had undergone. This lead to the greatest improvement in performance over time – a good indication of actual learning occurring.

Notes for teachers and players – if you want the best amount of learning, mixing a bit of differential practice with calibration work is the best for the long run. It will not only allow you to do what you want to, but it will give you the tools you need to teach yourself.

Other notes

I believe that one of the main reasons for a greater improvement within the groups which included some DIFFERENTIALwork was that there was an improved level of concentration during training. I cannot prove this directly, but it would seem obvious that, if you’re changing the shot by adding variance, it forces you to go through the mental preparation phase. This phase can be skipped out in the calibration training. A good analogy is if I were to ask you the same maths question over and over, you would soon zone out and not be computing anything in your head as you give the same answer over and over. Your performance would be great (as you would be answering quickly and correctly each time. However, if I were to ask you a different question each time, you would have to go through the process of thinking and calculating – which would make performance go down (speed of answer and possibly correctness), but learning in the long term would improve.

Also, not all golfers improved the most with COMB. Some improved more with the CAL approach, so while it is good to find generalizations which fit the majority (and most of the golfers clearly fit into the trend), it is important to know that everyone is individual, and coaching should be tailored to the student. You get to realize this the more you are with a person. Coaching is a two way process, and is more of a trial and error situation. Staring with generalizations can get the majority to better answers faster, but the answer may be different for everyone. It is only through testing different things that you will come to better answers and find out more about yourself.

Counter intuitive

A lot of this is counter intuitive, and it happened to shape many of my beliefs I hold now. I think more research needs to be done, but it is clear to me from my studies and further lessons that people of all abilities seem to respond well to variance. A lot of literature on motor learning now talks about how everything should be highly specific and we should practice with perfection in mind, but this study clearly shows the opposite (to a certain extent). The players who practiced context specific (CALI) improved the least. Players who hardly had any specific practice (DIFF) even won out against them. But it was the combination of both which showed the most improvements (COMBI). But one thing is for sure, the idea that “perfect practice makes perfect” is not true and may even be harmful to maximising learning.

But I am a scientific mind, and so until further research is done on players of all levels, it is not definitive whether the results would carry forwards. However, Anecdotally, it is no surprise to me that some of the best players in the world can perform some funky trick shots which they may never use on the course. And Tiger Wood’s ability to shape the ball is impressive, as he demonstrates in clinics. And he practices it too – Hank Haney states in his book (The Big Miss) that Tiger practices the 9 ball flights (high low and mid trajectory of fade, draw and straight shots). This variable practice followed by undoubtedly hours and hours of calibrational work has not done too much harm for him.

I can attest personally that, since I have been practicing more variable and differentially, my game has come on leaps and bounds. I now never struggle to calibrate a good shot. If I feel I am hitting it from the toe one day, I can quickly identify and change that pattern – much quicker than I could when I was practicing hours and hours of Calibration. Also, this skill seems to transfer to whatever technique I use. I often practice with silly/poor swing styles (to see what my clients are feeling), yet can still manage to get it back on the middle of the face.

Take Home notes

If you are going out on the golf course on the day, trying to calibrate one thing may provide the best results for you. But do not confuse this with learning. You will get much better learning long term if you actually mix it up a bit, and the most learning will come from a combination of both.

So every practice session you have, try to pick something to improve and then find a way of adding variability before zoning in on what you want. This can be applied to movement style as well as impact skills (such as divot control, strike control or clubface control). For example, if you are trying to improve your weight shift, try half of your practice trying to over-do it, followed by underdoing it (or even complete reverse) and then finish by zoning in on what you want.

Variable and Differential practice techniques may actually cause some performance disruption in the short term. Try to avoid using them close to playing or close to competition. A good practice schedule will include these elements, but will have them further away from important performance times. When I teach better players, I usually get them to perform more variable work at least a week away from major tournaments, often more. But it will usually be on a sliding diminishing scale.

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Thursday, March 13, 2014

Low point and Parametric Acceleration

This post includes a lot more technical detail than I normally talk about. I am going to discuss a topic that will hopefully spark some good quality discussions which can further our understanding of the golf swing, and specifically impact. I am also going to, in this and future articles, suggest the practical implications of this information.

Full credit goes to Chris Como for this information. He is currently doing ground breaking research on this topic and was kind enough to share information with me, which I hope can help some players and teachers. Also, Sasho Mackenzie has done some modelling on this topic and, as I understand, has worked with Chris on proving this theory. 

If you look at the below picture, it shows a pendulum swinging back and forth. Just like any circle with a fixed hub, it will have a very small ‘low point’, marked out in green (the reality is the lowest point of the swing is infinitely small). Hopefully, this is simple to understand. 

If a pendulum (or club) is swinging from left to right across the screen, we could speed up the pendulum by pulling the end of the string (or club) in the direction of the green Arrow. Forces want to line up in the direction of the pull, so the bottom end of the pendulum will try and line up with the dotted line by speeding up towards it. This has been coined ‘parametric acceleration’.

If we are pulling the top of te pendulum in the direction of the green arrow, not only does it speed the bottom of the pendulum up, but it will raise the overall height of the pendulum (as it is being pulled upwards).

But the act of pulling upwards whilst the pendulum head is still moving downwards neutralises each other. The result is a longer ‘low point’ in the arc of the pendulum swing. This is highlighted in red.

handle moving up, clubhead moving down = long 'low point'

If we are to apply this to the golf swing, look at the below picture. The pendulum is being swung along the hand path, which is moving down and forwards, before moving forwards and upwards. This dramatically increases the speed of the clubhead, and also creates a much longer and shallower low point.

What are the advantages of this?

1.    A longer and shallower low point can offer a larger margin for error. If the first point of contact with the ground is too far behind the ball, it will have less of an effect on the ball flight and control. Conversely, a swing which doesn’t include this pull in the direction of the green arrow will continue to descend. This will mean that the control of the first point of contact with the ground will need to be much more precise.

2.     More speed. The pull in the direction of the green arrow will speed up the clubhead, offering a mechanical advantage (much more speed with for the amount of physical effort applied).

3.   More compression. The player will be able to hit the ball with a more forward leaning shaft position (relative to swing direction), allowing the club to be delofted, hence lowering spinloft and helping the player hit the ball further for the same swing speed. Without this pull away from the ball, the player could only achieve this decreased loft by having the ball further back in the swing circle. The problem with this is that the player will have an increased angle of attack (steeper) and so spin loft (and hence compression) may not be improved. Also, the player may hit massive divots which need to contact the ground in the right place more precisely, lowering margin for error.

4.   Longer line of compression – with these moves, the angle of attack and dynamic loft through the impact interval will remain more constant (than without), offering a longer line of compression. I am not sure we fully understand what this means yet, in practical terms. But it could offer potential benefits to consistency of distance control.

So, is there evidence of professionals doing this?

Whilst 2D video is not the best at looking at these types of things (due to something called parallax, on top of the fact that the swing is a 3D motion), we can see, in the below video, a visual representation of this movement from front on. Please understand, there will also be an inward component to this move (as in the grip of the club being pulled away from the ball to target line). But, I will talk more about that in coming articles.  

You can see clearly the hands raising through the hitting zone. Even more so if you look at the coupling point (the point where the two hands meet).

Practical implications

So, if an optimal hand path moves up and inwards (towards the golfer), we need to understand how to do this – or what are our options?

The first thing to realise is that, if we are going to be pulling upwards, at some point we have to get the coupling point low enough so that we have ROOM to pull up without topping the ball or missing it altogether. Where beginners go wrong is that their hand path through impact is usually too high to begin with, so any pulling up and in would result in a top shot. So usually, they don’t (or do and top it). Or, they move the hands down towards the ball through impact and have major struggles with low point control/consistency.

In the above picture, the red and blue lines represent hand path through the hitting area. The red line is that of an amateur, with the lowest point of the hand path being much further back (opposite right foot) and also being too high through impact. The blue line is more that of a better player, with the hand path being lower down. It also has its lowest point more opposite the right leg, and raises more sharply. This is a good visual to imagine when working on this concept.


Why is the professional’s hand path lower down? In almost all professionals, you will see what we call in the industry a ‘power squat’. This is where the player will drop in height. Often, this occurs during the transition between backswing and downswing, but some players do it earlier (during the backswing) and some do it a fraction later.

Take a look at the pictures of Tiger below

We can see in the above picture (pre transition) that Tiger's head has already significantly dropped in height.

Wow. That's a foot of height loss as he is coming into impact.

Also, see the below video with an iron to see the same basic movements. From 33 seconds on, we can see the head drop in height to create a hand path which is almost down to his knees.

This drop in height is created by a drop in hip height, and usually an increase in forward flexion of the spine. 

the decrease in sternum height is clearly seen here (from yellow line to red line)

The raise

Now we have the hand path low enough, we have to raise it through the hitting area. For the best players in the world, the hand path is at its lowest point around the area of the right thigh, before it moves up and in. So, how do we get the hands to move up and in? We have a few options.

1.       Get the sternum further away from the ball
2.       Allowing left shoulder to raise through impact.
3.       Shorten the radius of the swing (bending arms)

Out of our 3 options, with tour players, we more commonly see 1 and 2. However, This below video of Jamie Sadlowski shows him exhibiting all 3. For those of you who don’t know, Sadlowski is a World Long drive champion who has hit the ball 445 yards.

Through the hitting area, he demonstrates his sternum getting further away from the ball by going both upwards and backwards. With a driver, this movement will produce a more upward angle of attack on the ball, allowing for maximum distance, as well as the benefits described from moving the hand path up and in. The backward component (if excessive) may lead to problems with iron strikes, depending upon several other variables. Jamie also achieves moving the sternum further away from the ball via his hip height increasing through impact, created by literally jumping off the ground through leg extension.

Jamie also demonstrates his left shoulder moving dramatically upwards through impact. Moving the head backwards has helped create room for this, and so has having his spine tilted away from the target.

Point 3 is easy to see. Look how much his lead arm has bent through the hitting zone. This has helped Jamie to raise the handle away from the ball even more, allowing him to release his insane amount of lag right around impact – creating insane amounts of speed and distance.

The irony

The irony of most of this is that, the movements which produce a good hand path have often been frowned upon. Dropping your height and jumping up through impact, for example. The theory has been that, the less moving parts we have, the more consistent we can make the movement. Whilst this may be true logically, in a biological system which requires ‘margin for error’, more moving parts and more degrees of freedom may offer several benefits over something which looks prettier, more symmetrical and ‘tidy’. It is no surprise that Tiger Woods exhibits a lot of the traits described, and that he has also been one of the best (if not THE best) iron players in the  world over the course of his career, as well as a long hitter of the ball. Again, ironically, these good traits he has were almost taught out of him. Luckily for him, his body never really listened to his training, and he continued with what he did naturally.

Take home notes

So, in summary, if you provide an upward pulling force through the hitting area, you can not only create speed through parametric acceleration, but you create a longer low point (for more consistency) and the ability to hit the ball with a lower spinloft (more compression). You will also create a longer line of compression. All of these are good things.

Also, more degrees of freedom and more moving parts can actually be a good thing. Most teachers try to be too restrictive. Whilst this can work, and there are often times I do it myself (if I deem necessary), the idea that less moving parts = more consistency can be taken too far.

What amazes me the most is how our bodies are so intelligent. Tour pro’s have found these macro movements without being told about them, and often in spite of being taught the complete opposite. It also amazes me how the human body can organise so many moving pieces, all moving in different planes of motion, at different speeds, rates of acceleration etc, yet combine them all to produce the impossible; a ball which flies 300 yards down the fairway. Just a couple of degrees out and the ball is offline, yet we manage to do it on (almost) regular occasion. Without going too much into the theory of the uncontrolled manifold hypothesis, it is safe to say that we, as humans, are pretty damn amazing at organising all of these complex movements into one harmonious symphony. We should try and tap into our self-organising skills more often.

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I must mention Jon Hardesty for our discussions on this topic. It is also right of me to mention Chris Como and Sasho Mckenzie for their information on hand path, and also Brian Manzella for consistently bringing hand path to my attention.

Wednesday, March 5, 2014

Low point

Last week I talked about skill development in golf. This week, I will discuss an important element relating to your performance in golf, and then give example of how to improve it using a skill based approach.

Playing a round with my buddy from my junior golf days, we were discussing the topic of strike. He was a little out of practice, and suffering with some thin and fat shots that day (as I was too). Upon further discussion, I realised that he didn't have a really clear concept of what he was trying to achieve with the club at impact. This guy was a pretty decent player (12 handicap), so obviously had the ability to strike the golf ball, yet without a clear concept, he must have been doing the correct things more accidentally than intentionally. This is true of many better players; the subconscious mind can even override incorrect conscious concepts to produce the correct things, given enough practice. But, I feel things can be achieved quicker if the 'what to do' part is clearly defined, even if the 'how to do it' is more open to interpretation. So, what must we do in order to strike the ball correctly and eliminate fat and thin shots?

Top players have few things in common with one another, but a consistent theme amongst all tour professionals is their ability to control the low point of their golf swing. If you are to imagine the swing as the golf club being projected in a circle around your body (although this is not an accurate representation of what happens, for purposes of simplicity, this will suffice), the lowest point of that circle needs to be controlled in both height from the ground (up and down), and position relative to the ball; further forwards (closer to the target), or further behind the ball (further away from the target).

The swing could be visualised from front on as a circular shape

The best players in the world have the lowest point of their swings in front of the ball. This means that their divots will tend to start on the line where the ball rests, and continue further forwards on the target side of the ball. The lowest point of the swing (deepest part / middle of the divot) can be as much as 4 inches or more in front of where the balls rests. This means that the club head is travelling downwards as it hits the ball, then enters the ground, creates the deepest part of the divot around 4 inches forwards of the ball before ascending out of the ground and into the follow through.

As we can see above, the lowest point of a pro's swing is 4 inches in front of the ball. This means the divot (brown part) starts on the line the ball rests, and extends towards the target. It also means the club is travelling downwards as it hits the ball.

To make things more complicated, there is a relationship between the height of the low point and position. If the lowest point of the swing is the same level as the ground, the optimal position for the lowest point is around the same position as the ball. As the low point gets further forwards, it also has to drop in height, or we would top the ball.
In the above picture, the low point is far forward enough, but not low enough. This is why making solid contact with the golf ball is about more than just good weight shift.

What do poor players do?

Where poor players struggle is, they tend to have the lowest point of the swing behind the golf ball. The problem with this is that when their 'swing circle height' is too high, they will hit a complete top shot. Through frustration, they lower the swing circle height just a fraction, and now the shot becomes a minging fat one. The player thinks they have two wildly varying swing faults, but in reality it is just one fault - the bottom of the swing is too far behind the golf ball. This now requires incredible co-ordination to be able to hit a functional golf shot (and even if they do, they will not be optimizing other impact factors to create good distance).

This player has the bottom of their swing too far behind the golf ball. This then causes the divot to be behind the ball, commonly known as a fat shot. The ball has no energy, no distance, and player feel they have hit "too much ground".

Fearful of the fat shot, they try to "not hit the ground" - but then they just top the ball. A tiny variation in swing circle height willlead to a dramatic difference in contact point of the ball. 

With a better player, having the bottom of the swing further forwards offers more margin for error, as well as better impact factors to create more distance (decreased spin loft). So, by having the bottom of the swing further forwards, less is required of the player in terms of coordinating the height of the swing. To highlight this, please see the below two pics.

With  the bottom of the swing behind the ball, it is impossible to hit a decent shot. An inch lower (red line) and we hit a divot 10 inches behind the ball. An inch higher (blue line) and it tops the ball - we are stuck between a rock and a hard place.

The pro has a much larger margin for error. With the divot in front of the ball, the same height discrepancy shows less difference in result. An inch lower (red line) and we hit a small fat shot, which probably won't lose much distance. An inch higher (blue line) and we 'get away with' a slight thin shot.

Please note that the law of diminishing returns applies here; you can have a 'low point' which is too far forwards, where margin for error is reduced, and impact factors start to reduce distance and trajectory.

Low point control can be improved through technical ways, but my preferred method is through a skill based learning Approach. I will leave you with a video of Charles Howell. After the slow motion view of the swing, they do a close up of impact which neatly demonstrates what you have just learned. Please share this article on twitter/facebook - and sign up to the mailing list to get updates on the blog. Don't forget to join my facebook page - click here - adamyounggolfcoaching.

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Currently working for the World famous Turnberry Resort at the Golf Performance Academy. I am a golf coach who specialises in not only what to learn, but 'how' to learn. I am always looking to further education of myself and others, and improve knowledge and understanding so that we can be better golfers and coaches