I'm trying to get back some of the little speed that I used to have before I started training for ultras. You know, maybe try to run a 5k in under 20:00 (dream big, eh?). So I'm back on the track and, since I don't know what else to do, I'm running 400 meter repeats.
My question is: how much rest should I give myself between laps? Do I give myself lots of rest so that I can run the repeats really hard, or is it better to not have so much rest between reps, even if it means I can't run them as fast?
Any other advice regarding speedwork would be appreciated, too.