Over the past few years, I've been seeing my speed fall significantly. Cruising speeds appear to be down over 1mph. Sprinting speeds are way down. I used to be able to hit 30mph no problem on flat ground. Now, I often can't hit that speed even if trying my best, and definitely need fresh legs to have a chance of touching that speed even for a few seconds. Endurance is still very good -- I'm only seeing dropoffs where I need strength.

The funny thing is that when I'm out there, I feel like I'm a better rider. But the stopwatch and computer don't lie. My job doesn't let me ride as much as I used to, but I'm more deliberate about exercising in a way that will keep me riding better. On the other hand, maybe I'm just not trying as hard as I used to. I used to spend much more time in pain than I do now.

My question is are there any easy to read graphs that describe the general performance drops that occur with age? I'm trying to find the line between knowing when to apply more effort and when to know not to bang my head against something that's inevitable.