A blitzball (ブリッツボール, Burittsubōru?) is a spherically-studded ball about thirty centimeters in diameter utilized in a sport unique to Spira in Final Fantasy X and Final Fantasy X-2, where it is the main available form of entertainment. It can also be used as a weapon. Although blitzballs appear resilient against the powerful kicks of blitzball contenders, and the various hides of enemies Wakka and others strike with them, they are light; the material comprising the blitzball lacks the density to sink on its own, and even flies in an upward curve after receiving a Sphere Shot.
Blitzballers are swimmers who kick around this said ball. Swimmers have huge legs. Soccer players have huge legs. It should stand to reason that Tidus and Wakka’s bodies should look proportionally like Tyrannosaurus Rex. They’d have huge legs in proportion to their bodies. They would be able to kick a blitzball nearly a sixth the speed of sound at enemies on dry land.
Then again, if you pelt an animal with a volleyball at your speed…
DON’T DO IT!
…long enough, you’d probably kill it.