Law 24, Clause 3 of the Cricket rule book defines a fair delivery with respect to the arm:
“A ball is fairly delivered in respect of the arm if, once the bowler's arm has reached the level of the shoulder in the delivery swing, the elbow joint is not straightened partially or completely from that point until the ball has left the hand. This definition shall not debar a bowler from flexing or rotating the wrist in the delivery swing.”
A Brief History Lesson
The law against throwing has not changed in its essence since overarm bowling was legalised in 1864. Before the advanced development of biomechanical and audio-visual technology, this law was implemented by the on-field umpires using their own visual judgement. Testing in the 1990’s revealed that during a delivery virtually all bowlers flex and extend their arms naturally to some degree as it rotates around the shoulder. Thereafter, a set of tiered tolerance thresholds for the amount of allowed elbow extension were implemented. 10 degrees for fast bowlers, 7.5 degrees for medium and 5 degrees for spin bowlers. However, enforcing these measures became problematic. A study from 2000-2003 revealed that a zero tolerance threshold and the tiered thresholds had no or little scientific merit, as actions that looked normal to the naked eye had elbow extension ranging between 9 and 15 degrees. Following further studies conducted by the ICC, they decided to raise the elbow extension tolerance threshold to 15 degrees for all bowlers.
How is elbow extension measured?
Simply put, it’s the difference between flexion at upper arm horizontal
, as seen in the picture.
And flexion at release
, as seen in the picture below.
What would cause flexion and then extension of the elbow beyond the legal 15 degrees?
In terms of young beginners, it can simply be the incorrect muscle memory due to lack of strength or momentum as bowling is a very unnatural action. However, as we move onto older or more advanced players, the incorrect muscle memory is, in my opinion, generally due to compensation. Compensation for a perceived lack of pace, compensation for a perceived lack of revolutions / spin on the ball, compensation for a lack of strength, compensation for a biomechanically incorrect action, one in which various muscles are working against each other and not for each other or compensation for a lack of time in the gather.
The cause needs to be identified first, before you try and fix the action as a different cause would require different remedial work.
When it comes to compensation for a lack of pace, the remedial work = stop trying to bowl too quickly! If only it were as simple!!!
The problem comes in when, over time the body forms a new muscle memory, one which is biomechanically incorrect.
In the table below, there are suggestions for the possible remedial work that could be done according to the various causes of a bowler throwing.
||POSSIBLE REMEDIAL WORK
|Beginners; lack of an understanding and feeling of what it is like to keep the arm straight throughout the action.
- Visual aids such as iPads etc.
- Half-moon drill, repeat, repeat, repeat…
|Lack of strength upon back foot landing causing the hips to open up too early resulting in poor alignment and loss of power and energy, as well as throwing the bowling hand out wide along the incorrect line.
- Strength work in the gym
- Resistance bands placed around the bowler’s waist during the bound force a stronger bound and back foot landing, creating more energy through the crease.
- Jumping on a small trampoline
- Repetitive drills off of a few steps
- Slowly increase the run up, paying attention to a strong landing.
|Poor alignment of the arms in the gather, causing the bowling hand to be brought down along an incorrect line.
- Repetitive drill work off a couple of steps, repeat, repeat, repeat… you may need to exaggerate the movements at first.
|Release point beyond the vertical.
- Adjustment to where the bowling hand is taken back to; generally caused by the position of the hands in the gather or a hyperextension of the back.
|A lack of time in the gather resulting in no control of the movements, or possibly even too much time in the gather resulting in not enough momentum.
- The correct rhythm needs to be discovered, whereby the bowler still has momentum, but at the same time control over his movements.
- This is about trial and error, and honest feedback from the bowler.
|An incorrect angle of approach may force a bowler to have to redirect the line in which his muscles are working.
- Again, a little bit of trial and error, but this should never be too much of an issue to remedy, as the general rule of one line towards your target will more often apply than not.
|Lack of use of the front arm may cause the bowling arm to try and generate the pace on its own.
- Repetitive drill work off a couple of steps focusing on how the non-bowling arm is working.
|A mixed action can easily cause the bowler to compensate for the pain he knows he is about to come across, therefore forcing him to take the easy option; bowling is hard work.
- Find out what is easiest for the bowler to adjust - upper body or feet. Generally the upper body is easiest to adjust, although it is important to remember that each individual is different.
|Over-striding may cause the bowler difficulty in getting over his front leg and through the crease, resulting in a loss of power and energy.
- Repetitive drill work focusing on the length of stride. Beacons can be used as a visual aid in assisting the bowler. Generally the correct stride length can be measured from the bowler’s feet to the bottom of his chest.
- The run up and bound may need to be assessed as it may be a cause for the stride length.
All the points mentioned above are important in rectifying an illegal action, however the most important lessons that I have learnt in working with players who have been suspended from bowling are that this process takes time - the player needs to understand that such processes cannot be rushed. Each step needs to be mastered and fully ingrained before moving onto the next. Often, if it is his livelihood, he will try push through the process as quickly as possible, place emphasis on the need to master each step of the process so that when he comes under pressure he will not revert to old his old habits. AND MOST IMPORTANTLY the player truly needs to believe in the action!
St Johns College Cricket Head Coach