Floofballs
Vox on something I’ve always wondered: Why tennis pros reject balls before a serve (and what happens to the ones they do.)
More fluff ⇒ more drag ⇒ more time for your opponent to react. So they’re looking for a ball with less fluff for their first serve, and a floofier one for their second.
But while it is provably true that floofier balls are slower, and as Serena Williams’ coach points out, the more important (and potent) thing here is the mental effect of the ritual itself and not the actual Physics 🎾