Possibly two reasons.

If you drop weight for a peak race this may not be sustainable all year round.

and

The level of training at the peak may be too demanding and again not be sustainable all year round.

On the other hand, finding the highest level that is sustainable and then picking it up a little more for key races, rather than constantly up and down. I think this is what Joel Filliol works to.

I’d say that it’s something that most age groupers do rather than taking an off season then building back up again. Maybe the pros do it that way as they have the time?

i rode for 2.5hrs this morning….very slowly tho.
when i got back i ate a medium green salad, with a large tin of mackeral and a big dollop of home made hummus.

and i felt well fueled up afterwards.

What I meant really is that it is maybe more logical for endurance athletes like IronMen to be at a level where they’re consistantly fit instead of pushing for just the one big event.

I’m looking at this too. I can’t train to upper limits so have to try and train to a good quick average and good stamina levels rather than explosive. The theory sounds good.

It’s not peak if it’s sustained, it’s a plateau. A high plateau maybe, but still not a peak.