"The 33"-Road Bike Racing - Power on Flats vs. Climbs

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View Full Version : Power on Flats vs. Climbs


brianappleby
03-14-07, 12:51 PM
I've been training w/ power for a bit and i've found that i can hold a much steadier tempo (less up & down) when climbing at a given avg. power. This also happens at less percieved effort.

How does climbing compare to flats as far as power output is concerned? Is everyone better at climbing or is it just me? Are there any tricks to bringing my power on the flats up to match my power on a climb? Is this all just in my head?

Thanks,
B.


curiouskid55
03-14-07, 01:00 PM
Are you saying it's easier for you to make 200 watts on a climb tha making 200 watts on a flat?

Duke of Kent
03-14-07, 01:10 PM
There are probably a couple of reasons for this:

1) Very few roads are perfectly flat. Your power will fluctuate with the slightest change in the slope of the road.

2) Going slow, wind resistance is less of an issue. Your weight and the resistance it offers are the main players. So, a change in the wind is probably not going to affect your power output nearly as much.

3) Relating to both of the above: while going up a climb, presumably at a slow speed like 12mph or whatever, you're less likely to have very quick changes of slope and road surface than you would on a "flat" stretch. Basically it stretches out the time period to cover the same distance, and when the variations hit, they are also longer, and the fluctuations are more easily covered.

4) Also, on hill climbs, you can usually pedal through corners due to lower speeds. This helps maintain a steady power output, obviously.

I had a problem with this myself last week. I did a workout on a course that was essentially a crit layout. 1.4 miles, 15ft of elevation gain. Little undulations and a slight uphill for like 100m on two of the straights, very slight downhill on one of the others. My normalized power for the 20min was 316w, my average only 309. I also had to wait for a car and a bus for a short while each, but that doesn't matter too much. I would 350+ on the very slight uphill and try to keep 300 on the down side, but that was hard, given the downhill AND tailwind on the section (not to mention it was dark outside, and speed was the only thing I could monitor).


grebletie
03-14-07, 01:10 PM
If you check the Wattage group on Google, there has been a lot of discussion about this. For whatever reason, most people seem to be able to produce more power on climbs versus on the flats.

I wish I could tell you why, maybe someone else can. Nevertheless, it is a phenomenon that others have experienced as well.

merlinextraligh
03-14-07, 02:01 PM
I think, its mostly mental. Simply maintaing a decent pace on a steep climb mandates putting out high wattage.

It takes a significant mental effort to crank out high watts on the flats.

jschen
03-14-07, 02:06 PM
It would seem obvious to me that one's power on climbs should, all else equal, be equal to or higher than one's power on flat ground. To go fast on flat ground, you need to optimize power and aero together. How many of us climb in as aero a position as when going hard on flat ground? If we don't, why not? Presumably it's because we can generate more power when not being as aero.

Of course, the mental effort argument sways me as well. It's hard to put in 30% more power only to see 10% more speed.

Snicklefritz
03-14-07, 02:13 PM
I think, its mostly mental. Simply maintaing a decent pace on a steep climb mandates putting out high wattage.

It takes a significant mental effort to crank out high watts on the flats.

+1
In addition, on a hill you can't coast like you can on the flat...well I suppose you could but then you might fall over at some point.

I notice the same thing myself. If I do 20' field tests, they always come out better on a hill compared with the flat.

bitingduck
03-14-07, 02:34 PM
It would seem obvious to me that one's power on climbs should, all else equal, be equal to or higher than one's power on flat ground. To go fast on flat ground, you need to optimize power and aero together.

That's to go *fast* on flat ground. To hold constant high power on flat ground you just have to have a good feel for holding high power on flat ground. Your speed may then vary with your aeroness, but the power can still be high (i.e. you could be aero or have a parachute at the same power and you would just have a different speed).



How many of us climb in as aero a position as when going hard on flat ground? If we don't, why not? Presumably it's because we can generate more power when not being as aero.

Most climbing speeds are in the near-linear wind resistance speed range, so aero doesn't matter. If you live in socal (like you do), it's also easier to find nice places to climb a long time than ride flat a long time, so it's easier to get used to high power output climbing.


Of course, the mental effort argument sways me as well. It's hard to put in 30% more power only to see 10% more speed.

That's where racing helps, because if the extra power gives you a little gap that's slowly growing you can feel good about it, even if the speed difference is small.

waterrockets
03-14-07, 03:28 PM
It would seem obvious to me that one's power on climbs should, all else equal, be equal to or higher than one's power on flat ground. To go fast on flat ground, you need to optimize power and aero together. How many of us climb in as aero a position as when going hard on flat ground? If we don't, why not? Presumably it's because we can generate more power when not being as aero.

Of course, the mental effort argument sways me as well. It's hard to put in 30% more power only to see 10% more speed.

+1 Sitting up, pulling on the bars, chest open. Is there a more powerful endurance position on the road? (eg. not sprinting)

+1 to it being mental too... your brain senses how slow you're going on a climb and you keep the pace up because of that. On the flats, you can't easily notice that your speed has dropped from 22 to 21.

brianappleby
03-14-07, 03:35 PM
I indeed do live in northern california, where I can ride 3 miles and find some very decent hills, but finding a flat stretch for a 10-minute interval is considerably more difficult. As a result most (80%) of my training is on hills. Is my power on the flats going to suffer?

How does my body know the difference between flats and hills? Is a 7% grade really enough to change the balance of muscles i'm using? The mental aspect is challenging but i'm noticably over LT when putting out 315 watts on a flat (huffing & puffing burning legs etc.) but as soon as the road pitches up I feel like 315 is just at or below LT.

I suppose that I should try riding flats in the climbing position to see if that makes a difference.... If it's just a matter of being in a more efficient position that's cool. My fear is that riding the flats works some muscle that riding hills doesn't. I don't want others to have anything I don't.

nice to know that others have noticed this... it drives me crazy on training rides.

waterrockets
03-14-07, 06:07 PM
Another thing to consider is that higher cadence is less efficient. Since we all lower our cadence when climbing, it's more efficient. On the flats, your high cadence increases your HR, but doesn't offer as much power.

The tradeoff, of course, is endurance. Low cadence/low HR will fatigue your legs faster, so you can't put out that power for as long.

bdcheung
03-14-07, 06:10 PM
WR: I don't understand. If high cadence is inefficient, why can I sustain it longer (per your argument)?

Also, I tend to have higher cadence (100+) when climbing and lower cadence (80-95) when on the flats.

waterrockets
03-14-07, 06:43 PM
Higher cadence on the climbs is a bit odd... not sure about that one. Have you measured better power/HR at higher cadence?

Efficiency in this regard means power/HR. You can go longer at lower efficiency because the tradeoff is that your legs are more resilient at higher cadence. Lower cadence is harder on your legs, producing more power. Higher cadence is harder on your CV system, producing less power, but preserving your legs.

zimbo
03-14-07, 07:35 PM
I have definitely observed this phenomenon. During my most recent 20-minute test, even though I was trying *extremely* hard to keep my watts at or above 335 the entire time, as I look at the data there is an obvious correlation between increased wattage and decreased speed. In other words, it's much easier for me to keep the wattage up when going uphill than downhill, even when the grade is slight and even when I'm conscientiously shifting to keep even power to the pedals.

--Steve

brianappleby
03-14-07, 07:58 PM
I've thought about this too, and tried to circumvent it by pushing a harder gear at a lower cadence on flats. I normally have this idea after I'm already in a good deal of oxygen debt, so maybe I'll try it sooner and see what happens.

On the cadence/HR note: I've also found (for me) that although high cadence seems less efficient for the HR or percieved effort, I also seem to recover faster

waterrockets
03-14-07, 08:08 PM
On the cadence/HR note: I've also found (for me) that although high cadence seems less efficient for the HR or percieved effort, I also seem to recover faster
Yeah, this is exactly what Dr. Ferrari discovered when he researched Kenyan runners, who shuffle with short strides, but run marathons among the fastest in the world. They don't have that "wall" at 20 miles like everyone else when their legs start to fail.

At super-high cruising cadence, Lance was such an amazing talent that his heart and lungs could handle the extra load from the inefficiency, still produce gobs of power, and reap the benefits of not destroying his legs as fast as everyone else. As I have discovered, that kind of cadence isn't for everyone :)