I actually just got back from running some 400s. I’ve been doing CT’s running man now and then, and I’m glad that I’m not the only one who finds going all out with those rest intervals impossible. The one time I did try going all out, I had to lay down on a bench for 5 minutes after my 3rd lap until my legs stopped quivering.
I’m a fighter, so I try to incorporate sprint work twice a week or so, in addition to one or two mid-distance run, but lately I’ve switched more to tempo running than sprint work. I find that if I sprint in the morning, it’s hard to train very effectively that night, or even the next day at times. Tempo work still does wonders for my wind, without totally wearing me out.
For conditioning, now that the weather’s getting nice in New England, I think I’m also going to try to do some strongman medlies, my gym has tires, chains, sleds, medecine balls, sledgehammers, and the like, so I should be able to put together some pretty interesting medlies.