Interesting (maybe) point...we did some research on height of contact and serve speed for our programme (wheelies) and with a rough contact point of 2m high, the maximum speed, with no spin, to keep the ball in was 84mph. The best servers in our sport hit 100-110, so they have some serious spin on their "flat" serves.
My point is that most rec players think "flat" or first serve means no spin, which is entirely not true!
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