Australian scientists decode the mysteries of spin-bowling

Australian scientists have now used mathematics to unravel the secrets of one of cricket’s most vital components – spin-bowling. They believe these findings can help bowlers develop new varieties and keep the batsmen at bay.

Scientists from Victoria University and University of New South Wales in Australia pointed out that variations in the proportions of spin applied to the ball from slower bowlers could have significant impact on the outcome of the delivery. To compute the flight paths, researchers took into consideration numerous forces – gravity, drag force, the ball’s vector velocity and finally, the ball’s lift or Magnus force.

Calculations subsequently revealed that small variations applied to the ball’s rotation can cause significant problems to the batsman even before the ball lands on the pitch. Researchers said that top-spin includes dip in flight, side-spin causes side-ways movement through the air and off-spin causes the ball to drift across the spin.

Ian Robinson from Victoria University said, “We found that if the total spin is kept constant and a small amount of top-spin is added to the ball at the expense of some off-spin, the length at which the ball pitches can be reduced by as much as 25 centimetres - an amount that batsmen can ignore at their peril - despite little change being observed in the side-ways drift.”

He also mentioned the cause for drift – “On the other hand, a small amount of side-spin introduced to a top-spin delivery does not alter the point of pitching significantly, but can produce 10 centimetres or more of side-ways drift.”

Garry Robinson from University of New South Wales said, “When a side-spin component is added to the spin of a ball bowled with a mixture of off-spin and top-spin in equal proportions, significant movement occurs in both the side-ways direction and in the point of pitching, of the order of a few tens of centimetres.”

Scientists are hopeful that their findings – journal Physica Scripta – will provide spin-bowlers with the technical know-how required to master varieties required to keep the batsmen guessing at all times. The findings are descriptive enough and prove what fans across the world have seen every time Australia’s Shane Warne spun a web of deceit around batsmen. His leg-spinners drifted sideways in the air as it hoodwinked the batsmen as he lined up for a stroke. The drift was employed to great effect as Warne dismissed Mike Gatting with his “ball of the century”.

Similarly, off-spinners are seen extracting significant drift when employing their orthodox off-break delivery. India’s Harbhajan Singh managed to get the ball to drift in the air away from a right-hander. Ravi Ashwin manages that delivery with ease now and is perhaps the best exponent of off-spinning variations in present day international cricket.