Oval Test: Anderson Bowls Dravid – Late Swing?

The final test between England and India is underway at the Oval. As has been the case throughout the series, the fast bowling is again dominated by swing. For the most part, conventional swing has been observed, mainly because it has been easier to retain the shine on the ball in the wet/lush conditions. Of course, vigorous polishing of the ball, readily evidenced in this series, helps this process as well. On occasions, typically later in the innings when the ball surface roughens up a bit, reverse and contrast swing have also played a role. Regardless of the type of swing, the commentators are often heard using the term: “late swing.”

So, is late swing a real phenomenon that only occurs under special circumstances? Or is it just an optical illusion that fools batsmen, spectators and commentators? Well, I have news for all you cricket fans out there. IT IS ALWAYS LATE SWING. A swinging ball (regardless of the swing type) always follows a parabolic path such that most of the sideways movement occurs during the later part of the flight, as shown in the figure. For all you science geeks, this is because the sideways deflection (swing) is proportional to the square of the elapsed time.

The reason why only some swinging deliveries “appear” to swing late (while others are seen as swinging “normally”) is due to the perception generated by the initial ball direction. Case in point, Anderson bowls Dravid in the first innings at the Oval on Thursday. Sir Ian Botham promptly remarked: “a little bit of late swing there.” Well, it sure was, and the full yorker length didn’t hurt either. However, what made it special was that Anderson aimed the ball towards fine leg and it swung towards the off side – that is what fooled Dravid – he was attempting to work the ball towards the leg side. In fact, that is exactly what swing bowlers should attempt for maximum effect. The ball should be released in a direction that is opposed to that of the expected swing. So bowl an outswinger from wide of the stumps and angle it towards fine leg and bowl an inswinger from close to the stumps and angle it towards first slip. The batsman will typically react to the initial direction of the ball and then get a “shock” when the ball swings (late) in the opposite direction and removes his middle stump!

Rabindra Mehta
Sports Aerodynamics Consultant and NASA Scientist based in California.
(rabi44@aol.com)