I was an absolutely terrible athlete (pick the activity), but also did a bit better as the race distance shortened (even though my training was nearly 100% LSD).
Here's my "training" routine for my PR quarter:
1) Race national marathon. Run ~LSD pace to 20 miles; alternate walking and jogging for three miles; survival shuffle for three miles; last 300 yards, sprint like an absolute demon, trying (and just failing) to beat a guy I ran most of the first 20 miles with.
2) Seven days of typical post-marathon easy running.
3) Run an abysmal seven-mile race (reduced to ~8:00 miles at one point), get passed by three old guys with about a mile to go, and sprint like a demon over the last 300 yards to pass them back, just catching the last guy at the finish.
4) Three more days of LSD.
5) Go to track for timed quarter: 57.6--first time under 60. Sorry I didn't get a 220 split, too, because it was surely a PR (I rigged considerably in the homestraight).
I dunno whether my (crappy) endurance "made up for my lack of speed." I do think that by exhausting myself aerobically in those races (trust me, I was maxed) and then sprinting those crazy final 300s, I was almost exclusively working my anaerobic system for about 45secs.
I also don't think this is a "training" regimen I'd recommend for anyone trying to PR a quarter; but it does show that by injecting a little bit of hard sprinting in a mostly easy/aerobic routine, it was possible for a person *without* a lot of fast-twitch muscle--or any other kind of muscle (me)--to run a fast (relative to my other, even worse times) quarter.