Originally Posted by
Keithm
I've been trying to improve my speed for a while now and found that my legs kept getting bigger and bigger but I wasn't getting much faster. by looking at people that I ride with, I can see that they have much smaller legs, but are still far faster than me. This is when I went online to find the key difference between my riding and theirs. Several people, fast people had said that with emg, their glutes produced half of their downstroke and were active for a very long time during the pedal stroke. When I assesed myself, I realized that I had a very small contraction at the top of the stroke, and that was it. surely if I made my glutes stronger, I would be significantly faster. It's not that they arent contracting as in some people, they just arent putting a lot of effort in. It would stand to reason that if they became large enough to become dominant, they would do more work. and I do drills for for cadence and one legged drills(could deffinitely see how these could make a marked improvement). thanks everyone for posting.
Here's the thing, the glutes only function for a certain number of degrees of rotation of the crank. Sure, you can utilize them well past a horizontal-crank, and you can find ways to measure that they're still contracted. But that extra amount is wasted because it's pushing in a different direction than where the crank & pedal is moving. You can be pushing down at the bottom of the stroke all you want, but all that force is going into stretching the crankarm, not spinning the pedal around. That's wasted power. So it's better to fire the glutes only during the portion of the pedal-stroke where they actually generate motion at 90-degrees to the crankarm:
While it's the single largest contributor to the whole pedal-stroke, it's still a small portion of the total. You'll also want to work recruiting and managing the other muscles as well so that the entire total will be larger. I did a month of training at the OTC in Colorado in the early '90s and they showed me some force-plots around the crank. One football player had generated some of the highest pedal-forces they've ever registered, +250-lbs on a single pedal!!!
But he was really slow on the bike. Turns out close to half of that force was used to push up the dead-leg on the upstroke of the other side.
As others mentioned, you can also bend over to move the glutes usage area further down the pedal-stroke, but it also starts later and you'll still end up with only 90% of the rotation coming from glutes anyway.
There can be power-reductions from being bent over so far without adequate training. Your diaphragm will be more constricted and you may not be able to take in as much O2. And your hamstrings will be stretched more, again, dropping power elsewhere in the crank-rotation, such that total-power produced will be lower even
with higher utilization of the glutes.
However, that's still only part of the equation. Unless you are going for 200m-sprint or RAAM records, peak muscle-strength and pedal-force is not the primary limitation for average cruising speed. That's more a function of the aerobic system and how much oxygen it can process and deliver to your muscles. You balance the aerobic versus the muscular system with gearing so that they are both working at the same percentage of their maximum. It sounds like you're over-working the muscles, getting sore and cramping and thinking that it's your muscles that's letting you down. I bet if you use a heart-rate monitor, you'll find that you're barely taxing your heart & lungs.
The general rule-of-thumb is that higher-gearing (lower-RPMs) will tax your muscles more and your heart/lungs less. Conversely, lower-gearing (higher-RPMs) will tax your heart/lungs more and legs less. So, in your case, using 2-gears lower while riding with the other guys will let you go faster and further before your legs give out. Using 3-gears lower may tax your heart/lungs too much and blow those up before your legs feel a thing. So you'll want practice using your gears to optimally balance your muscles with the aerobic systems.