Where does a bowler's pace come from? Spin compared with run-up

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By comparing the speed gun measurements of a spinner's stock delivery with their straight (fast) ball variation - and a fast bowler's stock delivery with their slow delivery variation (usually an off-cutter) it looks as if the spin accounts for 10-15 mph of the delivery.

Therefore, about 10-15 mph of the energy into a delivery goes into generating spin.

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What about run-up?

Well a 'big spinner', with a fast arm speed, who bowls at 55 mph off a few slow paces to the wicket can often deliver a fast ball variation at 70 mph (maybe a little more, but I would suspect chucking) - whereas a normal quick bowler off a long run-up will bowl at about 80 mph.

Therefore, assuming that the spinner's and quick bowler's arm speeds are about the same - then a long run-up probably generates about an extra 10 mph for the quick bowler.

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So - taking the bowler's straight delivery off a few paces as standard: spin subtracts about 10-15 mph while a run-up adds about 10 mph.

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