also, given the hectoring tone i am receiving, your message might be received better when they signal openness, ask how you do what you do, or in individual conversations. it might not work in a lecture hall style setting and approach where you chew them out as a group in a locker. it might work if x friend comes to you instead, says, i wish i had your speed, or i wish i knew how you did it, and you then give your speech, ok, do some long runs on off days, and do some of the recovery stuff slower, etc. or you grab the 2 or 3 guys and instead of lecturing them, build them up, i think you could be a minute faster, if you want that, here's what you do.
sometimes it's how you approach people. pick your timing. part of being a leader is knowing how to reach different people different ways with the same message they might fight when sent another way.
but also know when to just drop it. if you were pushy about it already, the well may be poisoned, and you might as well wait for them to come to you.