Huge difference in standing versus seated power

lanierb

I've been struggling with the fact that there's a huge difference (>10%) in my standing versus seated power. Some numbers (I'm 36yrs and weigh 176lbs/80kgs):

[some standing]
FTP: ~300
20m: ~330
5m: ~370

[no standing]
FTP: ~265
20m: ~295 [typo fixed]
5m: ~330

The "some standing" column would typically involve maybe 50% or so standing for the FTP and 20m and 95% standing for the 5m.

Some examples: in a hill climb race last weekend I did Pavg=298w, NP=305w over 62 minutes. This involved a fair amount (maybe 50%?) of standing. This morning I did 2x20 (w/5m rest at 125w) at Pavg=275w/276w, mostly seated except for some small hills. The hill climb race took way more out of my system (breathing/HR etc) but the 2x20 probably made me more muscle sore afterward.

Is there anything I can do to bring my seated power up to the level of my standing power? I've been trying to do seated 2x20s but it's not helping that much. Also, how common is this?

Lanier

frenchyge

Is that a typo in the "No Standing - 20m" figure?

Is it possible that the difference in performance is due to race vs. training motivation? Do you do your training seated, but race with some standing to keep pace?

Squint

Is your cadence lower when standing? It could be a problem with your powermeter, whichever one it might be, in that it's not very linear.

I find I generate less power standing, as does one of my friends, at almost any duration.

Did you mean 295W for your seated 20MP?

RapDaddyo

I agree with Squint about the cadence question. It sounds as though you may be turning a low cadence in your seated efforts. I think it's easier to apply more downforce on the cranks standing (weight), but more difficult to maintain a high cadence. I can do equivalent short duration power standing but at durations longer than ~1 min, it's seated hands down but I turn a fairly high cadence.

lanierb

(typo fixed)

Yes, my cadence is much lower when standing (70 vs 90). I'm using a powertap SL, which doesn't use cadence as an input so I doubt this is the problem. My hill climb times are much faster when standing and correlate well to calculated power for the time, distance, and ascent, suggesting the difference is real. Also, I'm pretty sure that reducing cadence when seated doesn't make much difference to anything (maybe even reduces my power output), but I suppose I could try a low cadence interval next time out just to be sure.

Lanier

lanierb

It's not motivation because the difference is there in training as well. On local hill climbs I have to stand about 50% of the way to get a fast time even in training. Also, in one race a few weeks ago I decided to sit most of the way even up the hills because I was trying to experiment with the fact that I produce less power that way but have lower CdA. Suffice it to say that it was a disaster. I used up way too much energy early in the race because I was seated when I should have been standing, then died at the end.

One more thing: If I do a 2x20 on a hill and stand a lot I can do 305/305. No way can I do that seated.

Lanier

frenchyge

If the difference only manifests itself during hill climbs, then I agree with Squint and RDO - your gearing is too high to let you climb at your preferred *seated* cadence, and thus you are losing power. Standing cadences tend to be much lower, so there's less of an issue when you stand and you can keep your power up.

RapDaddyo

How would you characterize your seated pedaling "style." Do you try and apply power throughout the stroke, downstroke only, upstroke only, or what? And, have you experimented with higher (not lower) cadences seated?

lanierb

I don't think that's quite right. It's on flats that I can't generate the same power (because I'm generally seated). At that point I'm going 25mph and can choose whatever cadence I want. Also, even on the flats if I stand up my power goes way up.

Hmm. I suppose I could try using a really low cadence even on the flats that mimicks my standing cadence. I'm not sure I've ever tried that, probably because most people tell you to use a high cadence all the time.

RappDaddyo: I'm pretty much a pedal pounder, meaning I pound the downstroke, at least when I'm tired that's what seems to work (when I'm fresh everything works!).

Squint

What's the formula that the PT uses to calculate power? The SRM one is well known and it cannot calculate power without cadence. While the PT might not use cadence, it might use wheel RPMs or something. Otherwise, it's hard to calculate power from torque alone.

The other reason cadence might be relevant is because, at the same power, you pedal with more force to generate the same amount of power. If your powermeter isn't linear then it maybe reading high at higher torque/lower cadence at the same power.

I'd check it by hanging different amounts of weight from the pedal, doing the math, and seeing if your PT is fairly linear.

You're not using normalized power or ave power w/o zeros, are you?

frenchyge

I have a difficult time generating as much power on the flats as I do climbing, but that has nothing to do with position since I typically climb seated. Your posts about standing power have all mentioned hills, so are you comparing a hill climb interval (w/ standing) to a flat interval (seated) in terms of power?

I believe the reason it's easier to generate high powers while climbing is because the greater chain tension and lower momentum allows us to generate more torque for a longer period of the pedal stroke. To get that power on the flats you'd need to really fire the downstroke quickly to create a huge peak torque. Normally, the bike will immediately accelerate forward and reduce the chain tension, causing you to lose the ability to keep the torque on for much of the stroke.

Instead, I'd suggest finding a long, gradual incline that allows you to keep your comfortable cadence while seated, then try a 10-20 minute interval standing, and compare that to the same course done seated. If there's any difference between my *sustainable* 10-20 minute power standing v. seated, I'd expect it to be lower while standing (as long as the route is the same for each, and I'm able to keep my cadence in a comfortable range while seated).

bikeguy

Never seen anybody stand half the time while doing a TT but I've noticed that having about 5-6 standing efforts of about 10 seconds helps relieve the extreme burning sensation I get in my butt + makes me feel better. I would expect that standing for several minutes during a short TT would decrease performance. I've recently thought about doing a 10 minute effort standing all the time to see if it increases my seated power output. Interesting post lanierB. I've also found my flat speed has increased after switching to a 50x12 and spending a good deal of time at 75-80 rpm.

-Bikeguy

flapsupcleanup

This is something I've thought about also. PT has to have cadence to calculate power because power is torque X speed. It measures torque with strain gauges in the hub. The speed term is your body's speed (cadence) since you want to measure your body's output power. Now the PT will read power without a cadence sensor hooked up so I'm guessing the hub must calculate power using the other cadence function (I forget what that's called) it generates internally from your torque peaks, two per revolution.

acoggan

The same as the SRM: power = torque x angular velocity. The only real difference is that with the PT the measurements are made at the hub, not at the crank, so that 1) the torque is reduced or increased, depending on the gear ratio and frictional losses in the chain, and 2) the angular velocity (of the hub) is increased or decreased, again depending on the gear ratio.

FWIW, I also generally produce significantly more power standing vs. seated, but only for ~1 min or less. I assume the difference is due to the contribution of my torso and arms to my anaerobic power output. Beyond that length of time, however, I'm better off seated, provided that I have low enough gears to keep my cadence above 65 rpm.