I'm another resistance rollers guy. I know some people can sprint hard on them, but as hhnngg1 says, I don't quite see how. OTOH, I have no problem with that, because even trainer sprints aren't the same and my A events don't occur in March anyway. I don't start sprint work until well after the roads and light are good here. I'm still doing base. Too cold here to be safe today, so I'll do an hour of endurance on the rollers. Too cold tomorrow, too, so the group will do snow play in the mountains.