Training & Nutrition - How does muscle usage change with posture?

I've been searching the web for some good info on this. An animated diagram would be great.

When you're bent over in the drops, are you using your glutes more than when you're on the hoods? And does that add to your speed as much as the increased aerodynamics?

And if you're very upright, like on a comfort bike, do you use your lower back muscles (like maybe the iliopsoas) more?

I had also read somewhere that climbing in the drops a lot could cause your back to hurt, but why? What muscle is straining here? When I want to go fast on my mountain bike, I try and hunker down real low and that's when it feels like my butt is getting more of a work out, so it seems like it would be better to climb hills in a bent over posture, too, so that I can make better use of the stronger glutes.

Anybody have any insights on this?

I'm gunna generalize from my own observations, and I've no journal articles to back this up, but....

This is gunna sound silly.........

I actually think I ride slightly differently when the wind changes!!! :eek: When I'm hammering into a very strong head-wind, I tend to get a bit lower and back a tiny bit, and seem to do more pulling, therefore using more hammies and lower back. When I'm riding with a strong tail wind, I seem to stay high and move a little forward, and feel like I'm using more quad.

And climbing while seated!?!?!?!?! Forget about it -- that's a whole different world!! :) I tend to go way back and low, and can't get ANY power at all -- hopeless! I have to get out of the seat all the time.

Your legs definitely work in a different range of motion in relation to your torso when you change position, thats obvious. You use all the same muscles, but those muscles are either more strectched or tighter. In a tuck position, lower back and glute muscles are stretched more, and in an upright position, lower back and glute muscles shorten.

One thing to consider is that when you tuck down too low, your thighs get very close to your torso, which impairs your breathing. This can also impair bloodflow to the legs...think about bending a hose and what happens. Its a tradeoff between aerodynamics and power/endurance...more aero and less power/endurance in a tuck position...less aero and more power/endurance in an upright position. A more upright position can really open up your chest cavity and help your breathing, so its good for climbing, especially since climbing is relatively slow so aero isn't that important. But on fast climbs with mild uphill grades, a tuck position can become important again.

Try different positions in different situations and see what works best for you.

This is gunna sound silly.........

I actually think I ride slightly differently when the wind changes!!! :eek: When I'm hammering into a very strong head-wind, I tend to get a bit lower and back a tiny bit, and seem to do more pulling, therefore using more hammies and lower back. When I'm riding with a strong tail wind, I seem to stay high and move a little forward, and feel like I'm using more quad.


That doesn't sound silly at all. That's pretty much the observation I've made. I ride in the drops about 85% of the time, so these are the only changes I'm really able to notice.

See, I was thinking that my lower back comes in more when I'm more upright. But 85% of the time in the drops, huh? Wow, that's a lot. Don't your arms get tired?

I never noticed the diferent muscles while riding since I stay in my saddle the entire time...but I dont do extended steep climbs, so the ones I do which are short, I just accelrate aggressively (sometimes outright sprint) before I hit it, then drop 3 gears and just hold cadence as much as I can....usually I come out of it at about the speed I would normally cruise at.

However I do notice when I ride more upright I feel more powerful...but that's most likely just me throwing my weight into my pedaling...the mtn biker side of me...I didn't even know I was using my weight until it was pointed out to me....goes to show why i gained so much more muscle in two months of roadbiking than I gained in 8 months of mtn biking. I also noticed I cant hold high cadences when in the drops, but that might have to do with my guttius stomachus (aka: beer belly), than anyhting else. However I do ride almost exclusively on my hoods, and I find it quite comfortable.