I'm not sure what you mean by leg-endurance? There's peak-power/force your legs can apply. Then there's muscle-efficiency, which is how much power/force you can generate for any given oxygen-consumption. There's power-generated at LT, which can improve tremendously with training, yet VO2-max & absolute hasn't improved very much (this shows improved efficiency). There's continuous-power output at various time intervals, 3/5/20-minutes. Endurance in the cycling sense is being able to go long distances, like 100-miles at a time. Which is really more an exercise in pacing and eating/drinking.
Sure, if you're doing hill-intervals, you should be completely 100% spent, blown-up, gasping like a fish-out-of-water at the top. If you've got anything left to give at the top of the hill, you didn't go hard enough. Then coast down the back side to recover on teh downhill, then push up the next hill (or turn around and go back up the hill you just descended).
In doing time-trials, there's also a variable power-output strategy that's faster. Rather than maintaining the constant same HR up and down a hill like on a flat-TT, you can actually do the course faster if your push yourself slightly above LT going up the hill, then use the downhill to recover. The actual amount above LT will vary depending upon the size of the hill & grade of course. But the idea is that you lose more time by slowing down for a uphill than what you gain by the higher-speeds on the downhill because the amounts of time spent on each is different. So you miminize that loss by pushing harder into the anaerobic zone on the uphill to spend the least amount of time at slow speed as possible.
But for what you're doing as far as training, push it all teh way.
Just make sure you've got the base-miles and pedaling-form down first or else you're risking injury.
Last edited by DannoXYZ; 10-04-06 at 01:07 PM.