Q for those who do hill intervals
 

I do hill intervals once a week - typically a 4 to 4 1/2 minute hill at 6-8% grade 6x with a 4-5 minute rest in between. In the past I have gone out hard ("all out") on each one - as a consequence my times (predictably) go down from first to last interval. On the last 2 I am not likely at lactate threshold on average (as measured by powermeter - although HR is at it). Based on some other cyclist's advice I am going to try (starting today) balancing the efforts and hit all 6 pretty close to each other - so less than all out effort on first couple and hopefully better effort on last 2.

For those who do hill intervals - what's your take on these 2 alternatives?

you need more recovery time (10-15 minutes) between intervals. rather than going all out from the bottom of the hill, try to accelerate throughout the hill

the second part of your comment makes sense - the first part is inconsistent with everything else I've read about the rest between intervals being equal to the interval duration. On what basis do you make that recommendation?

A 4 to 4.5 minute is darn hard interval, much less on a hill. I'd vote for going by perceived-effort and HR and staying above LT so that your HR increases to max by the top. Each successive one will probably be a little slower, but that's OK.

I agree on the rest-interval, I only recover to 50-60% of MHR and that typically takes just the downhill ride to recovery fully. Maybe the full interval time if I'm out of shape, but never more than 3 minutes from MHR really.

It depends on what you are trying to improve. If you want to do better at hills in general, then the second option of holding back and making all of your efforts close to your LT without going over it will get you the better results. If you only have hills that last 4 or 5 minutes, then go again as soon as you get back down and turn around.

If you want to use the hills to improve VO2MAX , then give yourself more rest between intervals and do each one as hard as you can. If your last two intervals don't reach your LT then stop, you've had enough for that day.

4-5 minutes is a perfect hill for vo2 max intervals. It's too short for a good threshold workout.

Go for a steady effort. It will feel easy for the first 30-60 seconds. By the 3rd minute you will want to stop, but just tell yourself you're over half way. If you do have a power meter, aim for about 112-115% of your functional threshold power. I'd say you're better off going by speed than by heartrate if you don't have a pm. Equal recovery/work intervals is fine. You should have a hard time finishing 4-5 reps if done right. You can try to work up to 6 as you progress.

good perspectives - thanks. This is about VO2 max primarily and hills secondarily. I do 2x20 intervals on another day and my long rides (1x/week) have incredible hills on them (.5 to 2.5 miles).

I tried this yesterday and it was a very different feeling than my previous times (all out efforts). I was able to do 6 all averaging about 320 watts (I'm at 290 watts threshold), all within the same time frame (4:30). It did feel "easy" the first 1-2 and last one was hard. I'm not using a HR monitor but it was hammering pretty good at end of last ones.

At above threshold, is it right that heart rate ought to max out? The reason I ask is that when I do VO2 max intervals (5X5), my heart rate certainly rises above threshold, but it plateaus at about 8-10 beat below max. In fact, I haven't seen my observed max heart rate in about a year.