Yes, I know that Maria Mutola wears no-heel spikes in her 800 races. However, keep in mind running on your toes is a fallacy. Everyone's heels touch the ground for at least a moment, even Tim Montgomery's in the 100. Thus, if you are doing intervals, you might want a little cushion. Yes, Lightfoot, I use my sprint spikes, obviously, when I am doing really fast work. But for something a little less speedy (for instance, if an interval was 400m at 57), I use heeled mid-distance spikes and my Achilles' thank me. Additionally, as you know us runners do not have limitless pockets and on sprint spikes there isn't all that much between your foot and the ground. Ergo, they don't last too long when you use them all the time. Ditto those wacky Nike Christmas tree ceramic spikes that are in the shoes. Heeled "training" spikes last much longer and can be worn in the sleet, snow, hail without worry. And BR is correct, that 100m guys would not wear heeled spikes often. However, you would be surprised how many intervals a 200/400m runner has to do. Please don't refer to my track knowledge as "crap."
Back to the subject - on Mr. White's topic, some female DID show up at the track last night, jogged a mile tops, and then did about 9000 ab drills. Yikes.