This time by a NASA scientist

New Delhi: Just as the mysteries of reverse swing have begun to unravel, a NASA scientist a schoolmate of Imran Khan has come up with a new theory of what he calls `contrast' swing.

Dr. Rabindra Mehta, who is also a sports aerodynamics consultant, says that England's fast bowlers in India have made the ball swing towards the smooth side after learning the new technique from former England and now Australia bowling coach Troy Cooley.

"Whenever an old ball swings, commentators label it reverse swing. Often though, it is not true reverse swing they are observing, but what I call `contrast' swing," writes Dr. Mehta, who has spent 25 years studying how a cricket ball swings, in the April issue of The Wisden Cricketer.

"For conventional swing (away), the ball is released with the seam angled towards first slip or fine leg, spinning backwards along the seam and with the polished, smooth side facing the batsman. The ball will then swing in the same direction as the seam is pointing.

True reverse swing

"For true reverse swing the ball is released in the exact same way, except with the rough side facing the batsman. In this case, the ball will swing in the opposite direction to that of the seam. But, if a sharp contrast in surface roughness is generated on the ball, so that one side is smooth and the other rough, the ball can be made to `contrast' swing with the seam positioned vertically (pointing straight down the pitch)." UNI

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