This is the fourth in a consecutive series of posts and the reader new to the series may benefit by starting here or even the post before that.
The Squire poured another glass of Te Mata, Coleraine, enjoying the heat radiating from the walls behind him and watching the sun set over the ranks of vines that gently undulated like a graph plotting the elbow angle excursion of a legal, quick.
Third Man could sense that great mind at work which once had inspired his old friend, the Portsmouth AFC goalkeeper, and occasional bowler, Arthur Conan Doyle.
Like any good factotum Third Man played along, bowling a long hop. “Is there any other point to which you would wish to draw my attention?”
“The angle at no point exceeded 15 degrees.”
“That was the curious incident.”
By this time Bob Marshall of EIT’s Department of Biomechanics had arrived.
“Bob, will you explain it to him, please.”
“It would seem that bowlers who can maintain a fixed elbow flexion during delivery can use humerus internal rotation to produce higher ball release speeds.”
“And faster rotations and a more manoeuvrable wrist,” continued the Squire, scratching the diagram atop this post in the dust of New Zealand’s best terroir
“The change in wrist speed is firstly a function of effective lever length, and second of the wrist distance from the internal rotation axis of the humerus.”
“Length d in the diagram.”
“The conventional spin bowler endeavours to maximize the effective bowling arm length.”
“My modelling predicted that the generation of wrist speed due to humerus internal rotation would be greater than any loss of wrist speed due to reduction in effective bowling arm length.”
“Bob’s conclusion was that bowlers who could maintain a flexed arm through delivery either consciously or owing to an elbow abnormality either of the fixed flexion or carry angle type had the potential to achieve substantially higher wrist speeds through the use of humerus internal rotation.”
“The ICC were looking elsewhere?”
“Here’s what they need to be looking for …” The Squire etched another diagram in the dust.
“In this elbow extension angle profile the arm flexes up to the first black line (front foot landing), stays constantly flexed up to green line (bowling arm reaches shoulder height) begins to flex slightly again as the arm moves up towards the point of release at which time the wrist is also furthest from the internal rotation axis of the humerus, only then does extension begin and continues through and beyond second black line (ball released), maximising speed of wrist rotation, or wrist flick.”
“But that’s a throw. The same could be used to describe the technique of an Olympic javelin thrower.”
“It is possible that this effect may be utilised legally to some extent by those bowlers who flex the bowling arm slightly through ball release,” said Bob.
“But the more natural and probably most efficient method to generate ball or wrist speed is to extend at the elbow through release as in throwing,” said the Squire.
“In throwing both elbow extension and humerus internal rotation are utilised to generate ball speed.”
“So, if we took a ‘bowler’ whose elbow extension angle was around 60 or so degrees and was then extended through release, but by no more than 15 degrees, say to 48 degrees his action would have the properties of a throw despite him having an elbow extension of 12 degrees from shoulder height to ball release.”
“Yep, under the present code with its 15 degree extension limit such a delivery would be legal,” said the Squire with a catch in his throat as the sun set over the scene, casting a gloom.
“And such an action has the potential to generate higher ball speeds and more rotations than the conventional bowling action, does not have the mechanical characteristics of bowling, and uses throwing techniques.”
“If it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck.”
“Which means that every coach in the world will be teaching youngsters how to perfect it. And if a bowler can get away with an elbow extension over the 15% limit, there’s an even greater advantage to be had.”
“Maybe if a coach sat in his bath, puffing on a cigar and figuring out how best to maximize revs he’d come up with a … duck.”
“Probably he already did that.”