Tuesday, July 15, 2014

Correlation and causation

This is a Topic which I deal with every day. I think it is one of the things which we should all spend some time understanding, as it can influence so much of what we see on a day to day basis. In fact, whole industries can and have been set up on a faulty premise of this topic, and many people have been duped or even damaged by advice given on a misunderstanding in this area. By understanding this, you set yourself up for a life of rationality, allowing you to see things for what they truly are, as opposed to how they may be presented.


What prompted this post is the fact that I see so many people get this idea wrong. They take things at face value, and make incorrect assumptions (or assume things too quickly). Why is this a problem? Well, incorrect assumptions can lead to incorrect advice, which can lead to detriments to your golf.


What is correlation and causation?


Correlation refers to something which happens In conjunction with something else. For example, if event A happens followed by event B (either simultaneously or shortly after), it could be said that A correlates with B.

Causation is simple. It is something which causes something else. If I push an object and it moves, you can say that I caused it to move. The two also correlate. My push and the movement happened simultaneously, so this is a perfect example of when correlation equals causation.


Evolution

It is a very big advantage for us to be able to make these links. If we made these links quick enough, it could ensure our survival in the wild, through avoiding danger or seeking things we need. If we can correlate the lions roar with needing to o get away, this is an advantage. Also, if we can correlate the sight of a certain tree with that of the food it possesses, we can be at an advantage over organisms which don't have that ability.

you had better correlate the roar of this guy with the need to run.
The only problem is, we take this automatic linking into almost everything.


Every living animal can do this on some level. A fly can find its way to food simply from following the scent of the food, detecting whether concentrations of particles are getting more or less dense, and changing its course of flight accordingly. But a fly is not saying to itself "the food is over there. It smells good, I had better fly there" as it doesn't have the ability to put these instincts into words to itself. As humans, we seem to be much more conscious of this process, simply because we can describe these things to ourselves through he power of our language.


Pirates


But there are always times where a correlation happens, but it is not caused by what correlated with it. A and B may have happened simultaneously, but it B could have been caused by a third influence - C. Or even, A could have been caused by B - a reverse correlation.


Think about this example - the decline in pirates causes global warming. There is a clear correlation between the two, but one would be foolish to say that the fall in pirate populations is causing global warming. This is a case of A correlating with B, but not causing it. Global warming is more likely to be caused by a third factor.

It may be that factor C, a change in society, has caused both A and B. Societal changes have increased our rate of pollution, and also changed things which have enabled us to stop pirates existing. This is a case of C causing both A and B.

Or, it could be that pirates don't like heat, and as a result of global warming, this has declined irate populations. Obviously this is silly, but wait until we look at other, golf related correlations and causations.

This is important, because a correct understanding will stop us trying to increase pirate populations as a global warming preventative.


And, in golf?

What if there was a study done where a correlation was found between hitting the ball a long way, and the separation between hip and shoulder turn? For example, if it was found that top pros who hit the ball over 300 yards tend to turn their shoulders 55 degrees more than their hips turn. E.g. Hip turn 40 degrees, shoulder turn 95 degrees. It would be tempting to say that this separation, known as X factor, causes longer distance as it correlates with it. It would then be tempting to extrapolate from that, and then proceed to try and get everyone and their dog to increase this X factor in an attempt to increase distance. A causes B?
X factor - and I'm not talking about the talent show


The theory is further strengthened when we find a scientific explanation for why this case may be true. Muscles are known to have a stretch/ shortening element to them. This is where, in order to contract to their maximum efficiency and effectiveness, they achieve this better with a short 'stretch' just preceding the contraction. Muscles act like elastic bands, apparently ;)

However, what if A didn't cause B. What if long hitting was caused by a different element, C. What if it was the professional golfers' flexibility which was allowing them to create this bigger X factor and thus more distance?



What if there were several causal elements - C, D, E etc? The ligament/ tendon lengths and insertions, the point specific strength ranges of the players muscles, their sequencing, their rate coding, strength and mobility of each muscle, or a ton of other stuff?

And what if other elements caused those things? What if the ability to control the clubhead at speed, along with genetic elements and thousands of hours of practice had developed the above things, which caused the clubhead speed, which had caused the distance.


Houston, we have a....

Now we have a problem, because we try to implement this bigger X factor into the player, but they don't have elements C, D, E. And they also haven't done the things which caused C, D and E yet. What would happen if you try to get a player to increase their X factor when they don't have the flexibility of a tour pro, or the mobility? You would end up pushing them out of their personal range, and achieve their maximum stretch too soon. At best, you would get less speed, less distance, throw the rest of the sequence off and affect impact variables negatively. At worst, you could injure the player.

yeah... umm... just get your shoulder turn to 90 degrees and hip turn at 
35 degrees buddy. Oh shit, sorry...... are you ok?



Pressure shifts

It's common these days to talk about pressure shifts in the golf swing. This relates to the amount of pressure felt under the individual feet of a player at certain points in the swing. A typical tour pro would have about 50/50 distribution at the start, around 80% pressure under back foot around late backswing! and then pressure shifts dramatically towards front foot (80% in front ) early in the downswing ( typically by the time the left arm has reached parallel). Amateurs not only do not shift their pressure nearly enough, but they also do not do it early enough.

image from Dr Kwon, a leader in golf biomechanics


This is great to know, but the information also needs to be exercised with caution. Simply shifting the pressure better is not always going to lead to the desired result. I say "not always" as it depends on a number of factors.

Say we take the hypothetical example of a typical beginner which is trying to lift the ball in the air. If you look at their pressure pattern under their feet, they may have considerably more pressure on their back foot throughout the swing. But it is not the pressure shift causing the poor strike, it is their incorrect concept of how to strike the ball causing the poor pressure shift pattern. I talked about concepts in THIS and THIS article

Why is this important to know? Well, if you simply get a player to shift their pressure like a pro without addressing the concept, there will now be a disassociation between the concept the player holds and the technique they are applying. Their pressure shift is being forced upon them in an attempt to control how they strike the ball, yet the player is consciously (or subconsciously) trying to strike the ball in a way which is contrary.

There is a REASON why a golfer would get into these positions.
And it is rarely because they haven't learned better positions yet.


Sometimes forcing a technique upon someone like this can work. I am not saying it doesn't. But it is an inorganic way of making the correct technique arise. Also, for a correct pressure shift to function correctly, lots of other pieces need to be in place. A more forceful pressure shift (like a pro) but with an overly leftward swing direction (like a typical amateur) can make all hell break loose.

I have seen many times where simply improving the player's ability to strike the ground in the right place has had an automatic positive effect on pressure shift, but without any awareness at all. In fact, the top pros predominantly have their amazing pressure shift patterns which were developed without any awareness of them.

See my lesson example to see one of these concept-led organic changes CLICK HERE

The lesson here is that, not only can things be reverse correlation, but often times forcing a correlation upon someone may need all the other correlatory factors to come with. It is possible to change more than one swing element at once, and good teachers can often find ways of doing multiple complementary changes with one swing thought. However, if you are an amateur, you would be wise to not try and copy what the top pros do without a deeper understanding of all the elements. Leave it to your teacher to help you decide what to work on.


Mental correlates

Golf psychology is also getting more popular. We are doing more and more research into this topic, and I am very interested in it myself.

When we look at the top players, we can see certain mental traits which are common. Look at the demeanour and body language of a player who is playing well. Head up, chest up, walking with a speedy gait. It would be tempting to say that these body language cues CAUSE good performance. But I wouldn't be writing about this is it were true.

how well is the above player playing? Guess... go on


Now, this can be relatively harmless (much so than technical correlates). If you are to force upon yourself a positive body language, it may not do you any harm. It might not make you play better (I could easily walk down the fairway looking like I am leading the tournament, yet be shanking it around the course). So in that respect, it is relatively harmless. Apart from the mental effort it requires to hold your body language positive whilst playing poorly.

There is some research showing that it may be negative though. I saw a study where depressed people were asked to repeat the mantra to themselves "I am happy". The results were astounding, it made them MORE depressed. So, there could be an effect where forcing a mental state upon yourself may have detriments.



So, what do you think is really causing a player who is playing well to have this body language? Chances are, how they are interpreting the situation to themselves is causing an automatic change in their body language. This is evolutionary ingrained in each of us. If you were to visualise a situation where you are very confident normally, your body would likely adopt the same posture. It was our way of communicating with each other before language developed, and is held in our reptilian brain.

So, rather than simply copy the body language or the words that a player is using when playing well, look at the underlying mechanisms behind them. I talked a little about this in my CREATING UNSHAKEABLE BELIEFS post. Needless to say, it would be more beneficial to deconstruct our belief systems which cause poor body language. The long term benefits of this would be positive body language regardless of how we are playing, and without the need to force it upon ourselves.

Maybe we should inform ourselves about ourselves, rather than stick a 'band-aid' on the body language




Another mental example

I'm going to use an example which is similar to something which is out there right now, but I am going to change the example subtly, so the point is the same but the actual idea is protected. I any case, I am not saying it doesn't work, just that we should be cautious.

Imagine a study found that the best putters in the world had a very relaxed jaw, as measured by pressure sensors on a gum shield. It would then be tempting to get people to focus on how relaxed their jaw is throughout the stroke.

Wait, so you're saying I have the makings of a good putter?


But what if the cause of tension was something else? And what if the cause of relaxation was something else! And what if trying to get a player to relax their jaw actually causes performance detriments?

Perhaps the good putter with the relaxed jaw is in a relaxed and confident state of deep visualisation, using parts of their brain which are creative and drawing past successes. Perhaps they have no awareness of their jaw pressure, but it is happening as a result of the above mental processes. The irony is, if you were to suddenly make the player aware of their jaw pressure, it may throw them out of this ideal performance state, as it contradicts the brain activity pattern which made the jaw relaxed in the first state. Oh what a paradox.



The same could then be true of applying a relaxed jaw to an amateur who is a poor putter. It may interfere with their visualisation processes and make them worse. There is also the chance it could make them better, but you should exercise interventions with caution.



Sociological

There are some ideas which become popular because of sociological Reasons. They then spread further and further until they are commonplace. They may then correlate with elite performance even though it doesn't cause it. There is even the chance it could correlate with good performance in spite of being detrimental to it.

For example, imagine that for years before instruction was popular, golfers rotated their hips and straightened their back leg naturally. Now, imagine a golf coach decides that they don't like this look, and feels that the swing would be more stable if you maintained the flex in your right leg (the same flex held at address). Now imagine that coach gets one or two successes on tour, becomes massively popular, and their instruction then seeps it's way into the entire industry as everyone tries to maintain that flex in the right leg.

Let's FORCE that knee flex buddy


What would happen over the course of time? This idea (meme) would then become mainstream to the point it is not even questioned. And all the top pros who have had any instruction would be doing this knee flex, people would look and say "look, all the top pros do this" and the meme would continue and get stronger and stronger. Even if the idea was detrimental to performance.



I am not a stack and tilt advocate (I simply do not know enough about their methodology to make a comment), yet I know that they were pioneers of a recent abandonment of this 'flexed leg' idea. As a result, more and more people and pros are going away from the flexed leg and towards straightening it, allowing the hips to move on a more natural tilt.

Say What!!!!!!



The lesson here is, again, just because something correlates with professionals or elite performers doesn't mean it causes it. It may even correlate with elite performance and be DETRIMENTAL to it.

As a disclaimer, I am not saying that having the feeling or keeping flex in the right leg is always a bad thing. Different people need different things, and a good coach will be able to prescribe the ideal feeling for you. However, I see so many amateurs obsess over the fact their back leg is straightening, when in fact it is moving as naturally as it should.



Conceptual

Golf coaches love to talk cause and effect. In my industry, I used to get frustrated a lot when coaches would talk about cause and effect in purely mechanical terms. A player may make a slightly inside backswing and then come wildly over the top, and it would be said that "the backswing caused the downswing". This would always baffle me as I thought " why is it I can make the same backswing yet come down differently to that player?"' Obviously the backswing didn't CAUSE the downswing.

An 'over the top' move tends to promote a leftward swing path, which will promote a fade or slice. It would be logical to say that the inside takeaway creates a situation where the player needs to throw the club back over plane, thus creating the slicing action. The problem with this line of reasoning, if it is false, is that we end up fixing the takeaway in an attempt to fix the slice. But if the takeaway wasn't the CAUSE then we are fixing something which has no relevance to the shot. This can now cause disruption to the player, as they now have a heightened awareness for their swing, yet their results the same.



But what if, hypothetically, the over the top move was a result of the player reacting to the slice they developed early on via their open face-to-path relationship? What if, in an attempt to bring both path and face more leftward (to make the slice more playable), the player player found the over the top move helped this goal. Now, no matter how much you try to improve the takeaway, the player still reverts back to an over the top move, as it is their way of achieving their ultimate goal of getting the ball closer to the target.

If we have the above understanding of this movement, we may be more inclined to fix the real cause first (ball flight). This is a case of reverse correlation, where the ball flight is causing the movements we see. We may be best served by reversing the ball flight for a while (creating a hook with the player) and watching the swing movements reverse themselves. If done correctly, the player can learn the better movements and achieve a better ball flight without thinking too much about how to do it. Not only that, but the ball flight is changed with the ball flight as an ATTENTIONAL FOCUS, which will improve transference to the golf course (as opposed to learning to change ball flight via a swing focus, which may break down when the attentional focus inevitably shifts on the course).

And if the takeaway doesn't improve (which is likely because, in terms of causes, the takeaway is. Not a big contributor), we can always clean it up after the ball flight has improved. But tell that to Ray Floyd and his major championships.



Kinetics and kinematics

Kinematics relates to what is moving. But kinetics is all about how and why it is moving that way. Think about it this way, seeing our hips rotate is the kinematics. But which muscles are causing the hips to rotate?

This is not always as simple to work out as it may seem on the surface. It is very popular for the last ten years or so, to look at the kinematic sequence of a player. This is the order and speed of movements and rotational velocities of the body segments (hips, shoulders, arms and club). Looking at a specific example, we see that in every top player, the hip rotation decelerates coming into impact. In some extreme examples (Rory mcilroy) the hips even move backwards through impact.


It would now be tempting to get players to try and decelerate their hips in an attempt to bomb it like Mcilroy. But, what if the deceleration was not something which was active (as in, the player is trying to decelerate the hips). What if it was a passive result of something else?

Imagine siting on an office swivel chair. If you were to lift your feet off the ground and swing your arms and upper body forwards as hard as you can what happens? The lower body moves backwards. This concept is demonstrated very nicely by Chris Como, in the below video

Click below for video


You can see that the act of him swinging the arms and the club forwards quickly, it drags the segment below it backwards (hips and legs').

So, could it be that, the deceleration of the hips is actually created by the acceleration of the upper (more distal) segments? Why is this important? Well, if we achieve our hip deceleration by trying to slow down our hips, we may slow the whole system down, and use muscles in the incorrect way (using muscles which slow hips rather than the muscles which speed up the upper segments). If we do it in a different way (training the upper body to accelerate harder at the right time) we get the same look on the graph, but we speed the whole system up, which is the goal.

This is a case of correlation (hip decel and speed) being caused by an external factor C. in fact, there are several other factors which may need to go in place to make this move function correctly. Rory mcilroy opens his hips extremely fast at the start before closing that gap down hard, to the point of a hip reversal. But this requires Rory's special combination of muscle insertions, flexibility, mobility, strength profile, sequencing of other body parts as well as ability to coordinate this all into an effective impact position.

Do not Try at home


Side note, it may be sometimes advantageous to tell someone to slow their hip speed, but to copy a graph or move just because a pro does it, without an understanding of how or why they do it may be problematic. A good coach will know when and how to apply this info.


Take home message

Just because something happens in conjunction with something else doesn't mean it causes it. Sometimes they both might be caused by something else (or a ton of other factors), sometimes the cause could be the reverse to what you think, sometimes there may be no causal link at all, and sometimes that link could be detrimental if it were implemented. It can also be harmless too, but it would be wise to exercise caution.

Just because a pro, or all the pros do something doesn't mean it is what you should be doing. Maybe the thing that they do requires a lot of complementary variables to be in place first. While It is almost impossible to fully know the causes or all of the causes to movements, being critical and sceptical can be a valuable tool.

This is not an attack on science. This is an article highlighting a concept which can help us get to more correct answers quicker. I am all for progression and improvements in our understanding. I know some of the guys who are progressing the science of golf right now are making sure they consult with great minds who are aware of this concept, on top of implementing new ideas with their pupils progressively, testing and readjusting as necessary.

I hope this made you think.

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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