Kana literally throwing the bowling ball into the pins was the best part of the chapter
Funny story, if this had been candlepin bowling (which is something Touma might've experienced living in New England--all of the bowling alleys closest to MIT are candlepin), it actually
would be against the rules to just throw the ball the whole distance
But in regular bowling, it's just bad manners to lob the ball a huge distance, not against any rule, as Kana said.