Quick follow-up on the previous post – back-of-an-envelope calculations on “appropriate” pitch lengths for junior cricket.
Taking average heights as comparator: [pitch length at age 10]=[adult pitch length]*([average height at 10]/[average height for adult (male)])
[pitch length at age 10]=20.12*(138/176) = 15.78 m (17 yards, 9″)
Alternatively, taking average bowling speeds: [pitch length at age 10]=[adult pitch length]*([average bowling speed at U11]/[average adult bowling speed])
[pitch length at age 10]=22*(58.9/93.4) = 12.69 m (13 yards, 2′ 5″)
Nearly 18 yards (based on average height) does feel too long at 11 and under; just 13 yards (from average bowling speeds) too close. Something in-between, then.
Perhaps 16 yards, in fact.
For these calculations, data was taken from the following sources:
average height data (in cm) from NHS / British National Formulary : https://www.evidence.nhs.uk/formulary/bnf/current/approximate-conversions-and-units/prescribing-for-children/weight-height-and-gender
average bowling speed data (in kph) from Pitchvision: http://www.pitchvision.com/this-graphic-shows-you-how-you-compare-to-average-bowling-speed#/
n.b. (1) for safety, perhaps, it might have been better to use maximum bowling speeds.
n.b. (2) see the caveats on the Pitchvision data, in the comments section, regarding average bowling speeds – if you have data you believe is more credible, do repeat the calculations.