Originally Posted by
pallen
That's odd because the study you keep referring to says....
That's odd, because I've cited numerous sources for my beliefs. I also haven't referred to the Korff study in several recent posts.
Another source (not yet cited) is Edmund Burke:
More than 150 pedaling mechanics tests have been performed by the US Olympic Committee since 1992. These tests have included more than 125 cyclists from road, track sprint, track endurance (e.g. pursuit), mountain, triathlon, and even disabled sports (principally below-knee amputees). The data set contains many riders at the peak of the international cycling community….
Cyclists of all abilities exhibit negative effective forces (i.e., forces applied to the pedal perpendicular to the crank but in opposition to crank rotation) during the upstroke (180º to 360º) in steady state cycling. As we have recognized at the Olympic training center, cyclists correctly sense that they lift or pull the leg up during recovery but do not lift the leg as fast as the pedal is rising. Thus, the pedal actually helps lift the leg.
Burke does suggest that some elite sprinters are capable of, and might even benefit from, effective forces on the upstroke. But it's clear that:
1) Even in those situations, it's a small amount of power.
2) No one reading this thread is in that league.
So, yeah. There's a lot of data which indicates that the overwhelming majority of cyclists do not apply power to the drivetrain on the upstroke, and all you're really doing is getting your leg out of the way.
And again, this isn't really a "platforms vs clipless" argument. It is simply that even when you're clipped in, you aren't really applying force to the drivetrain on the upstroke. All you're doing is getting your leg out of the way.
• Foot retention can increase power to the drivetrain, but its less efficient.
Yes, my point (and apologies if it got buried) is that it's the same as low cadence. A lower cadence produces more force, but winds up reducing gross efficiency. I.e. it feels more powerful, but is in fact less efficient. That's why there are very few situations when you'd want to mash.
• Pedal stroke technique is irrelevant. (the entire point of the study)
Actually, the purpose of the studies was to see what, if any, differences there are between pedal strokes. And again, both studies on pedal strokes indicated that intentionally pulling up reduces net/gross efficiency. (The Korff study indicated that there was no significant difference between "circles," "pushing" and "preferred.")
• The data is very clear: You don't apply power on the upstroke on flat, level, steady-state riding. The data does not address standing, sprinting, or steep climbing.
I believe I already addressed standing, albeit briefly. Here are the force vectors when standing:
Basically, at no time are you actually pulling the pedal upwards while standing. You're applying significantly more force on the downstroke, but also weighing down the pedal on the first third of the upstroke.
When seated, you're just lifting your leg. When standing, you have to lift most of your body, which creates significant negative force on the pedals.
Climbing shouldn't be any different. You still want to maintain a high gross efficiency, and apparently being on an incline doesn't make a significant difference to your pedal stroke. (e.g.
http://link.springer.com/article/10....421-011-1914-3)
Now, if you can produce some actual data which modifies or corrects my views, I'd be glad to hear it. Oddly enough, I
still haven't seen
any contrary data. That's OK. I'm a patient guy.
