Dynamic Squats

Building strength for speed. I don’t want to gain mass like a body builder. A friend of mine squats like mad and grew these massive thighs.

I read somewhere that the size of a powerlifters legs aren’t nearly as big as a bodybuilder. So I guess my question is, can I develop Max strength without putting on a bunch of leg mass? To do so- are dynamic squats the way to go?

Wouldn’t muscle “density” be the goal for a sprinter opposed to muscle size? (If there is a direct relationship between muslce size and strength) Because I think we all know you don’t need big strong legs to run fast.