South Africa's Height Advantage

At the end of the 2nd Test, and at the beginning of the 3rd, the Indian head coach Rahul Dravid commented that India’s fast men had got the ball the misbehave less than South Africa’s, and that this was probably down to the extra height of the South African attack.

Sadly, the ball tracking records for the current series are not being published. But the records for India’s previous series are available for the first two Tests, and they illustrate the problem posed by height.

The table below shows all the deliveries which pitched on a length of 7m (i.e between 6.5 and 7.49 m) for each fast bowlers. Keep two figures in mind.

First, the height of the stumps (i.e, the height a ball has to cross the plane of the stumps at to hit the stumps) is 76.03 cm (71.12 plus the bails plus the radius of the ball), or 0.7603 m.

Second, a cricket bat cannot be more than 96.5 cm long, including the handle. The blade of the bat is usually about 70 cm long on average, or 0.7 m.

Kagiso Rabada bowled 80 balls on a 7 m length in those two Tests in the 17/18 series. 18 of those passed at a height below the stumps. The average ball passed the stumps at a height of 83.3 cm. (7 cm. above the stumps). The standard deviation was 30 cm.

The taller bowlers get more variation in height compared to the shorter bowlers (Bumrah, Shami, Steyn) from the same length. Crucially, consider this difference (roughly 5-10 cm. extra variation in height) relative to the size of the blade of a cricket bat (70 cm.)

This is a different challenge compared to the one in England where the width of the bat is threatened due to sideways seam movement off the pitch. In South Africa, the batters face seam movement from time to time, but they also face this vertical deviation. The height of the South African bowlers magnifies this difficulty.