Australian brothers devise maths formula for spin bowling

TWENTY years after Shane Warne's Ashes "ball of the century", two Australian brothers have devised a mathematical formula to help replicate it.

Shane Warne

ENGLAND'S Mike Gatting was famously bamboozled by spin when the the Australian bowler Shane Warne dismissed him with the "ball of the century".

Twenty years on, two Australian brothers have come up with a mind-boggling set of mathematical formulae that could help aspiring bowlers to recreate Warne's lethal delivery.

The two physicists have published force equations showing how the pitch of a spinning ball is influenced by a head-wind, tailwind and crosswind.

The findings are conveniently released just before the start of the Ashes series.

Ian Robinson of the University of Melbourne, one of the authors of the study, admitted that the average cricketer "could not be expected to fully understand the details of the physics of the paper".

But what bowlers lack in mathematical skills, they may make up for in intuition, the authors said.

The study measured the impact of wind on "Magnus" force, the course-changing effect that occurs only with a spinning ball.

According to the research, the presence of a crosswind can cause the ball either to "lift" or "dip", depending on which direction the wind comes from and which way the ball is spinning.

When an off-spin delivery is bowled into a wind coming from the offside, the ball is lifted slightly, lengthening its trajectory, the study showed.

The reverse is true when either the wind is coming from the opposite direction or a leg-spin ball is delivered in a crosswind from the leg side. When a 14km/h crosswind interacts with the spinning ball, the point at which it hits the ground can change by about 14cm.

Garry Robinson, of the University of NSW, said: "The effects on a spinning ball are not purely due to the wind holding the ball up."

Peter Such, England's chief spin bowling coach, said that the physics of drag and drift were already being taken into account in training.

"We have our own models for these effects - we're all over it," he said. The study is published in the journal Physica Scripta. The first Test match between England and Australia is at Trent Bridge, starting on Wednesday.

The Times