University of WA weeds out cricket chuckers
by Cricketarchive Staff Reporter
DateLine: 20th December 2006
Biomechanics at the University of WA now have another way of sorting
cricket chuckers from bowlers. Already regarded as world-leaders in
detecting illegal bowling actions, the UWA group can now tell if a
bowler is purposefully using muscle power to over-extend his elbow to
increase the momentum of the delivery.
The group, headed by Professor Bruce Elliot, has set the standards for
bowling adopted by the International Cricket Council (ICC).
Over the years, the ICC has called on their expertise to adjudicate the
"suspect" deliveries of international players Mutiah Muralithran,
Shoaib Akhtar, Johan Botha, and Shabbir Ahmed.
Test careers can hang in the balance as players face suspension from
international play if they exceed standards set by the ICC.
UWA biomechanist David Lloyd said it was illegal for a bowler's elbow
to straighten more than 15 degrees during delivery - from the position
where the upper arm is horizontal to when the ball is released.
Until now, any aberration from this range of movement has been detected
by placing markers on body segments and frame-by-frame computer
analysis of the angular movements, Dr Lloyd said.
Now, by calculating the three-dimensional forces acting on the bowler's
elbow they can detect if a player is purposefully recruiting his
muscles to increase the momentum of bowling.
"Measuring angular velocity and torque around the elbow shows the
direction of muscle action," Dr Lloyd said.
If the muscles were working in the direction that straightened the
elbow, it implied the extension was being done on purpose, he said.
However, if no muscle action or action in the opposite direction was
detected, it was likely the result of technique or anatomical
variations, Dr Lloyd said.
Banned Pakistani pace bowler Shabbir Ahmed recently flew to Perth to
have his bowling action, deemed illegal by the ICC last year,
reassessed after intensive retraining.
Shabbir whose unorthodox bowling style has caused him constant problems
since his international debut in 1999 is nearing the end of a 12-month
Test ban after being reported twice by match officials in 2005.
"I hope to be cleared to get back to play South Africa next year," he
Wired for analysis, the 6'5" bowler, who has been coached to rectify
faults in his action which result in his excessive amount of elbow
extension, went through his paces for the UWA biomechanics team.
Long-time WACA cricket coach and director of Cricket Australia Daryl
Foster said errors in foot placement or of the leading arm during
bowling could translate into illegal bowling actions.
"If you correct the earliest dysfunction in the action, the rest
usually falls into line," Mr Foster said. "The mix between foot and arm
action is the key."
Shabbir had been working to change his front, non-bowling arm action,
and stop his head from dropping during the early stages of the
delivery, he said.