Originally Posted by
wphamilton
It's a matter of training, which is what you're getting at. I had the same argument with someone concerning fixed gears, the other guy saying that any ride is "25% harder" than riding with gears because of the extra spinning and me saying "no way". There is some increased load on your CV system from spinning faster. I think you are correct in both:
1. slower cadences (self selected from 60-80 specifically) have been shown to be more efficient than higher cadences
2. Cadences higher still (have been shown to be less efficient at the same power outputs. Sprinting, sustained, etc.
I think these differences are mitigated (perhaps eliminated) by training adaptations at given cadences.
The reason for the inefficiency of spinning is obvious if you remember that lifting legs essentially produces no power. The leg lifts take the same amount of energy whether or not your pushing a high or low gear, while you're transmitting more power to the wheel on your downstrokes in a high gear than a low gear, the trade off being that each downstroke on the lower gear is against less resistance, so takes fractionally less energy.
I'm an outlier as I cruise in a very high gear--in fact, I was so annoyed with a certain other poster today that just because I wanted to see if I could do it, I went up a moderate hill in 53x11 and I actually did pretty well. But here's the point I have noticed as a result of my riding habits: In the gears I ride, I can run in the low 20 mph range with a cadence of about 70 rpm. Somebody spinning at 100 rpm to go the same speed has to perform 60 leg lifts per minute more than I do, plus an additional 60 downstrokes. It doesn't take a lot of math to figure out there needs to be a really huge difference in the amount of energy and the cv load I'm expending per downstroke to make up for that.
Before I get accused by someone (not you, of course!) of advocating htfu, the 53x11 hill thing is a definite "don't try this at home" stunt. I have mutant leg strength, and I just put the 11t cog on my bike and am playing around with it. I did it in the middle of a 75 mile ride today after an 125 mile ride yesterday so it didn't do me harm, but it's definitely not going to become a climbing method I'll do often.I
I agree that spinning well requires a lot of cv adaptation. My "method" , such as it is, also requires adaptation in the form of developing muscle strength.