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Fast bowling actions and back injuries

Starfighter

Hall of Fame Member
I'm going to make this thread to talk about one of the most vexing issues in pace bowling, that of the so called 'mixed' bowling action. This is probably the major cause of back stress fractures. Since the 1980s when researchers at the University of Western Australia such as Bruce Elliot first started exploring the issue research has fairly consistently found that the main factor in back injuries is excessive twisting and flexion during delivery, usually associated with a large amount of counter rotation.

Disclaimer: I'm not a coach, so take as many grains of salt as you need.

Now, we must define what counter-rotation is. This is the relative movement between the shoulders and hips that occurs during a bowling action. Hip and shoulder angles are usually defined with respect to the popping and bowling creases - closer to parallel is open and closer to perpendicular is closed. I won't use the specific numbers for angles used in the scientific publications, as they're a bit confusing and vary between papers. In this the important phases of a bowling action are the contacts of the back and front feet, the greatest extension during the delivery stride, and the delivery itself.
A bowler may land on the back foot with the hips or shoulders open, closed, or both, but basically anyone who can get the ball down the other end will always follow a sequence from closed during the greatest extension of the delivery stride to open at delivery. The hips and shoulders will both rotate the same way throughout the action.
The counter part comes from the most common type - where the shoulders rotate backwards relative to the hips, starting off more open and ending up more closed. The other way does happen - this is simply defined as a negative counter rotation, but this is much less common.
The reason why is that all really fast bowlers seperate their hips and shoulders during delivery, with the hips being more open. This is more marked in bowlers with conventional than slinging actions due to differences in the kinematics and muscles used, but it will pretty much always happen.

Now - what is a mixed action? This is where there is a significant separation between the hips and the shoulders at back foot contact, or alternatively (and leading on from this) an action with what could be considered a large counter rotation. The amount of separation or counter rotation used to define a mixed action varies, recent literature favours 30° or so, and a large amount of counter-rotation is somewhat preferred in definitions - some bowlers maintain separations without it.

This is not dependent on the how closed the hips or shoulders are at back foot contact. While only chest on (open) or side on (closed) used to be recognised, the division is really arbitrary and modern literature splits it into three, with mid-way being self explanatory (and probably the most common style these days).
 
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Line and Length

International Regular
As a bowler I occasionally had back problems but nothing that kept me out for more than a week. I believe some of the current problems I have may be related to bowling - particularly on hard, artificial surfaces. Some time back a teammate (12th man at the time), who was into photography, took an action sequence of me bowling. Not too pretty when I look back at the photos. Perhaps I should post a couple.
 

Starfighter

Hall of Fame Member
The following diagrams are from P.J. Worthington's 2010 thesis A biomechanical analysis of fast bowling in cricket. This study is related to something a bit notorious - the infamous Loughborough coaching program that Jamie Harris so slated. It may be that just because faster bowler have certain features does not mean teaching them will improve pace, but I digress. The research itself is good.

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This diagram shows two different types of action, note the more open-closed-open sequence through to delivery. I'll also mention a common fallacy - how side on or chest on an action is has little to do with where the back foot is pointing. Many chest-on bowlers point their front foot sideways, and some bowlers with 'slinging' actions (a seperate topic) point theirs backwards - we don't say they're bowling back-on, because that's clearly ridiculous.

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This second diagram shows how the hips and shoulders are not at the same angle at back foot contact. This separation varies throughout delivery.
 

Starfighter

Hall of Fame Member
Now let's see what they look like in practice. We'll start with the chest action. This proliferation of this type really began in the seventies, I suspect due to change to the front-foot no-ball rule eliminating an advantage for side-on bowlers. Several great West Indian bowlers were very successful with in, which seems to have spurred its adopted and by the late nineties it was probably the dominant type, and it or mid-way actions closer to chest on remain by far the most common type. Further factors may include coaches encouraging dead-straight run ups at junior level - though many professional bowlers have at least a slight angle or inwards curve, the use of nets whose posts and gates prevent angled runs, and the decline of the importance in cut and swing compared to seam. I would note, however, that contrary to popular belief, there is no evidence that indicates that bowling chest-on is better for your back, in fact more chest on bowlers tend to counter rotate more.

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Displayed above are three fairly archetypal chest-on bowlers, Siddle, Rabada and Marshall, all with the shoulder at a fairly close angle to the crease. Others include Ambrose, while many bowers such as Donald and Steyn are fairly close to chest-on, though I couldn't tell you for sure if they're mid-way or not. Note the variety of back foot positions - Siddle points his sideways, Rabada at about 45° and Marshall straight down the pitch. Marshall also swings his body markedly less that the other two. Note that while all three are looking past the inside of the front arm here, this doesn't always dictate where the arm is placed earlier in the action. Marshall, for example, often placed his front arm over his opposite shoulder in his gather.
 
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Starfighter

Hall of Fame Member
Now we come to the recently recognised type, mid-way. These classifications being somewhat arbitrary, it was realised in the 2000s that many bowler are neither really side-on nor chest on. Mid-way inclined to chest on is probably the most common action these days, most bowlers running in fairly straight, gathering fairly chest on and closing off a little to be midway at back foot contact.

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Glenn McGrath and Brett Lee are two examples of this style, note that their shoulders are pointing more towards point or so, but they look just inside or down the line of their arm. Many bowlers who might appear to fall into one of the other two styles actually fall into this style.
 

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Starfighter

Hall of Fame Member
Side-on actions used to be the predominant type, indeed it was considered the 'correct' way to bowl. Prior to WWII slinging actions were predominant, having evolved from round-arm bowling where they are the only way to bowl fast. The big rotation of the body allowed a lot of work on the ball when spin was the only type of movement. As swing, and particularly seam became more dominant actions become tighter and more modern. At the time side-on bowlers had an advantage where they could have a very long delivery stride if they dragged their back foot a long way, under some interpretations of the back-foot no-ball rule. With the adoption of the front-foot rule this advantage disappeared and more open actions became a lot more common. The true side-on action is now as rare almost fast bowlers as the true chest-on action was a century ago. The discouragement of curved or angled run ups, and of bowlers ruling with the front shoulder pointed forward instead of a 'correct' running style further discourages this style.

From the eighties onwards a curious prejudice developed against the side-on action. This appears to be partly due to the success of chest-on West Indian bowlers such as Marshall, Dennis Lillee's back injury - though he actually bowled mid-way at the time - and the fact that it gives the impression of greater stress on the back, possibly due to the greater engagement of the back muscles. The greater difficulty in achieving the position of a straighter run may also have contributed. Bowing side on does not in fact impose greater risk to the back than other styles.

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Fred Trueman represents the final stage of the old, dragging style, while Richard Hadlee and Darren Gough are two more modern exponents, Hadlee being slightly more open than the other two. One notable thing is how little backwards rotation there is between back foot contact and the greatest extension. Though many side on bowlers do open up slightly as the bring their bowing arm down and forward, side on bowling is much more one movement, whereas chest-on bowling tends to see a much larger closure of the shoulders during delivery.
 
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Starfighter

Hall of Fame Member
Now we get to the mixed actions. Here's I'll be using the example of two bowlers, Ian Bishop and Pat Cummins, who have had multiple instances of back stress fractures and we can have a look at just similar they are.

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Both throw their bowing hand back over their shoulder early in their gather as if they were shaping to bowl more side on, however on the descent into delivery both swing their shoulders open and land with their shoulders fairly chest on. The third picture is the crucial one, as it shows the shoulders fairly open while the hips are fairly closed, markedly so in Bishop's case. Both kick their front leg substantially across their body (the kick is not yet completed in Bishop's case), their hips are very closed and there is a very large separation angle. As the leg is swung back towards the body the hips will open at the same time as the shoulders are closing, creating the counter-rotation. In the fourth picture, particularly that of Cummins, it can be seen that the hips are now more open than the shoulders - the reversal of the previous picture. This means that there as been a large relative backwards movement of the shoulders, which sets up very large stresses that were responsible for the numerous serious stress fractures both bowlers suffered.

Bishop's case is particularly notable. Firstly, it is one of the most extreme cases of a mixed action that I've seen, and secondly, it is subject to a misconception that I believe contributes to the continuing prejudice against side-on actions. It is often stated that the bowled side-on prior to his first back injury when in fact he did not, his shoulders were always chest on. He did try staying more chest on, but it is generally considered harder to alter the position of the hips than the shoulders and it is not surprising that he kept picking up injuries that would eventually end his career. His case is certainly not evidence against side-on actions or for chest-on.
 
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Starfighter

Hall of Fame Member
To easier show what is going on I'll use a couple of simple (and not to scale!) diagrams. I'll ignore the bit corresponding to the first two pictures in each sequence above - the swinging open from shaping early to bowl side on is not necessary, there are other bowlers with mixed actions who do not do this (like Cameron Green). It is simply a marked similarity and that motion may be a contributing factor in those two cases.

The hips are in red and the shoulders are in blue.

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This diagram corresponds to the about the third picture in the sequences of Bishop and Cummins. This is the point of back foot contact, and at it there is a large separation where the hips are more closed than the shoulders. The picture of Bishop above likely has an even more extreme separation than this diagram.

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The second diagram corresponds to the fourth picture, at a point of great extension prior to front foot contact. The hips have not changed position significantly (though it may move either direction, just not in this example). However, as the bowler has stretched out in the delivery stride the shoulders have closed off dramatically and in this example are now more closed than the hips having moved backwards relative to them. The arrow shows the direction of movement, it is this movement that makes up the counter-rotation in this example.

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This last diagram roughly corresponds to the fifth picture above, at the moment of delivery. The hips and shoulders are now both rotating the same direction, maintaining the reversal of separation that occurred in the previous.

This represents the most common scenario for a mixed action, and is likely to occur due to the combination of a chest-on landing and the hips being closed off either at landing or early in the delivery stretch. The opposite does occur, but appears to be less likely as the hips will usually be opened first as the leg and posterior muscles are the first activated, creating the 'hip drive' that coaches sometimes refer to, and which may even occur when the shoulders are still being closed. I'm not knowledgeable enough as to exactly why this pattern occurs, it often appears to occur as the bowling arm is thrust forward out of the gather before the shoulders are stretched out and rotated closed.

There are lots of other examples of this type of mixed action, including Shane Bond, both Waugh twins, Tony Gray, Craig McDermott and so on. Many bowlers, especially chest on bowlers, make the same motion, but not to a large enough extent to injure. Some are chest on all through their gather, other start more side on and swing the shoulders open before back foot contact. The Loughborough study, and several other studies, do also show negative counter-rotations, some to a large extent, but I can't think of any visually obvious examples. I suppose this could occur to a blower who gets side on early and then hunches their shoulder down in front of their hip, but that's hopeless speculation and there si simply not the detail in the literature to explore the intricacies. The point is that any significantly large separation between the hips and shoulders and a resultant large change in that angle is a primary observation associated with back injuries in fast bowling.
 

Pup Clarke

International Captain
Quality quality thread. Will be back later to give my thoughts and possible expertise

EDIT : Pat Cummins is a great example of a bowler with a mixed action. It looks like that still shot of him was taken a few years ago, and by all accounts he's done alot on his approach to the crease by being more open-chested, and not alllowing his back foot and hips to come round and overcompensate
 

Blenkinsop

Cricket Spectator
This is fascinating -- thank you.

I'm curious about James Anderson. Early in his career he was encouraged to change his action to avoid the risk of back injury, but it didn't work out and he went back to his original action. Since then his fitness record and longevity have been off the scale. Would you describe his as a mixed action or is it just unique?
 

Starfighter

Hall of Fame Member
Anderson's action is probably mid-way rather than mixed, though he does have some counter rotation there. Part of what concerned coaches with him was his head diving away, which was thought to indicate a bad flexing motion. However he didn't have that initial inward lean you see in the Bishop photo and to my eye twists far less. When he made his comeback he was perhaps little more chest on, more upright in delivery and a little less twisted, with his bowling arm in line with his front leg rather than outside it - the latter perhaps being an indicator of excessive flexure. His action basically hasn't changed since 2008 or so. It works for him but I wouldn't recommend trying to copy it.

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Left 2003, right 2016
 

Son Of Coco

Hall of Fame Member
As a bowler I occasionally had back problems but nothing that kept me out for more than a week. I believe some of the current problems I have may be related to bowling - particularly on hard, artificial surfaces. Some time back a teammate (12th man at the time), who was into photography, took an action sequence of me bowling. Not too pretty when I look back at the photos. Perhaps I should post a couple.
Yeah, I had back issues when I was 13/14. Nothing too serious, but was uncomfortable when trying to bowl. Basically a twinge across my lower back. Then I was fine until I stopped playing at 16. Came back at 24 quite a bit quicker and never had any issues at all. Always had a fairly simple action though.

I do have very tight hips now and a lower back that is sore when I get up each morning, which I suspect might be related to bowling. The old pelvic thruster is still in pretty good shape though.

Would be great too see that action sequence too L&L.
 

Starfighter

Hall of Fame Member
The other major factor is back injuries in fast bowlers is large amounts of flex, especially sideways flexion. An interesting note is that bowlers who twist a lot (have large counter-rotations) will also tend to flex their spine a lot. This can make a mixed action doubly bad. The actual mechanism of injury, so far as I know, is that when the spine is highly flexed the forces from bowling - which can exceed five times the bodyweight - are transmitted more through the joint facets and less through the disks, so there is less absorption and a greater stress is put directly on the bones.

There is, however, a tradeoff here. The amount of torso flexion is also correlated with how fast people bowl. Yes, it does seem the by literally bending your back you can bowl faster. The school of thought amongst coaches seems to be that a large amount of forward flexure is safer (though this certainly doesn't appear to apply to James Pattinson, who has a big forward flexure and has had stress fractures countless times), and some of the pace coaches (Ian Pont being one) have advocated that bowlers really bend over far in their follow through. Sideways flex (Lawson and Ferguson are good examples) is considered more dangerous and coaches generally try to avoid it. The bowling arm being well outside the front leg is one sign, and some such bowlers (like Green) will appear ad if they are hunching their outside shoulder and hip together.

Excessive flexure can be a tricky problem to fix as doing so may entail losing a significant amount of pace. Actions to reduce counter rotation, when present, will likely help, but if it is a problem without it then some action will be needed to keep the bowler more upright in delivery, which may mean bowling slower.
 

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