I’ve actually done enough riding this year to progress past the “start gasping for air every time you come off the downhill” stage of fitness. More books than I can list here have been written about training for cycling. Certainly, the success of the more systematic methods used by Lance Armstrong and such to win the Tour De France over and over again have gotten a lot of attenion if for no other reason than they use cool toys. But, for normal people who are not racing bikes, there is a pretty simple measure of fitness that is easily applicable without any sophisticated data collection tools.
I think all of the training jargon and mumbo-jumbo translate into tracking two things while you are riding:
1. How long can you ride before your legs hurt a lot and don’t generate power. This is typically somewhat longer than the longest ride you have done recently. I do mostly 20 mile rides, so I expect that a 30 mile ride would make my legs hurt, especially if i did it fast.
2. What is the low gear you use to climb most hills.
For as long as I’ve been riding, the main indication that I’m getting more fit is that I can climb hills in higher gears without blowing up. Pittsburgh is a nice area for this fitness measurement because while the climbs are not long, there are very few rides you can take without a bit of up and down. These rollers act like automatic interval training areas, and give you a constant indication of your fitness level.
So there you have it. The way you tell if you are getting in shape is if you can climb that hill one gear higher than you did before.