The Mechanics of Bowling

Recent research has shown that very few fast bowlers pass the scrutiny of the slow motion camera. In secret tests many leading fast bowlers were filmed while bowling in games and even some who were considered to be ‘squeaky clean’ have failed to come in under the 10% flex of the bowling arm permitted by law.

The laws of physics could have told us this but it is interesting to have it confirmed. I am not really sure what that tells us other than it is difficult, if not impossible, to bowl the ball with a perfectly straight arm.

The sad thing is that much that has passed as good coaching theory in recent times has exacerbated the problem of suspect actions and has not worked to overcome the injury problem that it was designed to do. Some high-profile fast bowlers have had to undergo remedial work on their action in recent years because of reports by match referees. Others may get the tap on the shoulder following the secret filming.

Two bowlers who have undergone remedial work in the past because of referee reports are Brett Lee and Shoaib Akhtar. Brett Lee is considered to be a front on bowler while Akhtar is very side-on. How is it that they have been accused of having suspect bowling actions?

Brett Lee modified his action some years ago in the hope that he could overcome back problems. He was supposed to have a ‘mixed action’ and the suggested remedy was to keep ‘straight lines’ with the bowling arm, from set-up to the target, and in the process he changed his bowling arm ‘load up’ position to keep the arm closer to, and in front of, his body.

What this did was to cause him to have to use a lot of shoulder strength in his action to generate the same arm speed. With this adjustment came variations in his bowling stride length that in turn changed the point of landing pressure to the heel of his front foot. This has subsequently led to his ankle problems.

To allow for the generation of arm speed it required that he speed up the opening out of his front side in the delivery action. That, in turn, caused a need for the arc of the bowling arm to be shortened so that it could keep up with the fast releasing hips and shoulders, to avoid over-rotation of the body at the point of delivery. The end result of this is that the only way the bowling arm can catch up is for the elbow to bend during the bowling motion.

Shoaib Akhtar has a similar problem but for different reasons. Because he is moving with so much forward momentum from his run-up, his ability to create a timely degree of separation between the hip and shoulder angle in the jump is often compromised. This leads to uncoiling issues out of back foot touchdown from which his rapidly spinning upper torso is often in danger of over-rotating at point of release. This creates the same problem for the bowling arm as it tries to keep up. As with Brett Lee, the only way for it to do so is for the arc to be shortened by flexing the elbow.

So while Brett and Shoaib appear to be very different in style the bowling arm is just an expression of what is occurring with hips and shoulders. Unless these are loaded appropriately in the jump then the body will compensate in some way. For many bowlers the “flexed and rotated spine” at release (the greatest danger to the lumbar spine) may have been modified, but the super intelligence of the human nervous system has achieved this by contravening the laws of cricket!

As Newton pointed out so many years ago, in movement we are an “action/reaction” system. If we set the body up appropriately for the task and let it happen the nervous system will reward you. If, on the other hand, we try to manipulate parts of the “reaction” the nervous system will be forced to modify the ‘action’!

The most efficient bowling actions, such as Glenn McGrath’s, are set up by the run up, leading into the leap. The run up and the leap are the only parts of the action worth training consciously. After that it becomes a series of explosive reactions, so get the run up and leap right, and the rest will follow naturally.

The run up is used to provide momentum. How this momentum is used is then the key. The energy generated must be stored in the body, and this is achieved by coiling the body. The transition from the predominately forward momentum into predominately angular momentum describes this process termed coil.

The coil is similar to the action of wringing a cloth – the body is, in effect, twisted. The shoulders rotate past the line of the hips, to create a degree of separation. Once the body is wound up it can be unwound quickly generating bowling arm and, subsequently, ball speed. This is why small men can hit hard and bowl fast. It is all about coiling and uncoiling with momentum.

In bowling, this act of coiling is best achieved in the leap. The bowling arm drives up to begin the leap.

As the bowler leaves the ground and the bowling arm continues its arc back towards the head the front shoulder comes round towards the bowling arm in response. This sets up the critical degree of separation between shoulders and hips.

The degree of separation in the coil in the leap, set up by Dennis Lillee. Note how the shoulders have rotated more side on than the hips.

As the bowler comes out of the leap, the front arm extends as a balancing mechanism. This is a balancing act, and a reaction to the downward movement of the body as it comes in to land. This is why front arm coaching is a waste of time. It happens instinctively if set up right. If it is inappropriate it is just reflecting the inappropriateness of a previous action!

If the coil hasn’t been achieved in the leap, the bowler will be forced to coil at landing. Landing while the top half is still coiling can cause injuries and this is what is referred to in the ECB coaching manual as a ‘mixed action’ and was what happened to Brett Lee with his original action. If the bowler, such as Glenn McGrath, rotates the shoulders past the hips into a coiled position while in the air, a ‘mixed action’ cannot occur.

The action of the lower half of the body coming around in the jump triggers the top half to begin opening out for back foot touchdown. It is essential that the back foot landing should be on the ball of the foot to further optimise the forces generated through the run-up and coil. The bowler then has the forward momentum to come out of the landing up, over and around his front leg. At touchdown the ground reaction forces add to the drive of the front leg out and the front foot touchdown results in the arm accelerating out to release.

The key to an efficient and safe bowling action is to wind up the body properly in the first place. This is achieved by the setting up of a degree of separation in the leap. The use of the bowling arm in starting the leap is the key. A good running action with sufficient momentum generated into the jump will help the drive upward of the bowling arm as an extension of the arm action in the run up.

One of the fallacious theories on bowling preaches that young bowlers should ‘keep straight lines to their target’ as happened with Brett Lee. It is true that a bowler needs to be square on to the target at release, but they need to get there by rotating the shoulders to the bowling hand side and then opening them, and the hips, to the target as they uncoil. The result is that they end up facing the target.

Even the supposed ‘front on bowlers’ such as Malcolm Marshall and Curtly Ambrose have to create a degree of separation between the shoulders and the hips. Without this rotation a bowler must use shoulder and arm strength to bowl the ball.  And no matter how strong they are they will struggle to avoid over rotation! All movement depends on some degree of rotation.

If the front foot plants prematurely because of an inappropriate loading, the bowler will be forced to release the shoulders early by falling away. Another option for the bowler is to bend the elbow to shorten the arc so that the arm can catch up with the quickly rotating torso. Often, bowlers are not even aware this is happening until someone accuses them of ‘chucking’.

Technology and science is an important tool for the betterment of understanding of how we can make bowling more efficient and safe, but it is essential that the science that supports this research is well founded. Without this we are likely to continue to complicate the teaching of the art and fail in our aim of making fast bowling safer for its young and vulnerable practitioners. In fact we are likely to contribute to what we are attempting to avoid!

Greg Chappell
Ian Frazer

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