Forgive the intrusion, but are intervals THAT good?
I think so too, for a number of reasons:
Efficient use of otherwise wasted 1 hour slots. 1 hour is long enough to warm up, do a few hard intervals, warm down and it’s short enough to be able to recover quickly before your next slot, unlike a full-pelt 3 hour session that leaves you wrecked for days.
Counters the typical amateur athlete tendency to make easy sessions too hard and hard sessions too easy – 100% effort intervals are easy to gauge effort levels for (try not to black out or vomit too much).
Gets me out of the office at lunchtime (also makes my colleagues think I’m some sort of awesome sportsman, how little they know…).
The majority of my training time is short lunchtime interval-style sessions. Although I don’t race, I can feel the benefits when I occasionally get out on a 2-4 hour ride at the weekends. I don’t think that it’s possible to make big advances in endurance by doing just short interval sessions, but it certainly seems possible to maintain fitness by doing them.
In reply to the OP, I’m not following a fixed training plan this year, but in the past I’ve read Friel’s book and drawn up plans based on that. His blog is also very interesting and fills in a few gaps. Currently I just try to go on feel, but keeping in mind the general principles about nutrition, session content and cycle planning that I’ve picked up.