Originally Posted by Cypress

I would think reducing intensity would aid with the knee issue. I would also warn against HIIT on reduced sleep. I'd get more endurance in, then try to get your intervals in on days where you know you'll be getting more sleep (if possible) that night.

Originally Posted by Doge

Depends a bit on age and how hard you are training. Sleep is when you rebuild. Late 30s+ you are not going to build so much. For elite kids and low 20s picking up 2 more hours a night makes a difference. Target by several elite trainers is 9-10 hours after working out. A lot of working out is weight based. I think if you don't do weights, you can get by with less.

I would think the numbers are related. I can speak to the knee and sleep. My kids trainer/s had him elevate legs, read in bed, keep body prone state when he could.

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Depends on goals. I have seen huge speed gains adding weights - and sleep, vs miles. But most like miles, because they like cycling. Few USA races need a pile of miles.
My kid won the CO state crit championship with a quick acceleration off the front on 2 hours/week on the bike, 5 in the gym and about 9 hours sleep - in a military academy. Some talent was missing, and he has a lot, but point is - made by both his trainers, you don't need so much miles for speed. Note he did not even enter Nats RR for 1st time in years, and ITT was even too long for a good performance. But speed up, due to weights and sleep.