I don't think that's the typical paradigm, bit if it's the case for you, that would be a way to explain why the flats are more fatiguing than hills...provided the higher cadence required to match the designated wattage doesn't drive your cardio system anaerobic.

Which part is hypothetical? I thought it was true that work causes fatigue, and that more of it causes more fatigue than less of it.

it certainly seems logical that applying higher force would take more work and therefore be more fatiguing. Just pushing your foot into the floor is more tiring than just standing there.

But in both cases you're doing exactly the same amount of work in a given time period.

Which is more tiring: climbing 100 ft using 6" stairs or climbing the same height in the same time using 12" stairs?

You know what's really fatiguing? Arguments over physics and biomechanics in the 41.

Why do your muscles fire for a shorter period of time on the flats? Mine don't. I agree it doesn't feel the same but that is primarily due to a difference in inertial load seen at the cranks.

+1.

Wut?

Same wattage, same cadence, how and why would your muscles "fire" for a longer portion of the down stroke climbing versus riding on the flat?

Yeh, drag is drag whether it's gravity or wind so it should feel the same. But it does feel different for me sometimes and I think I know why. It's a combination of things:

1) with mostly short, rolling hills I don't slow down enough and wind up putting out about 50% more power on the hill. I know, we stipulate "same power", but saying and doing are two different things.

2) When it's flat, I tend to slack off a little to recover when fatigued and I'm not going as fast, nor putting out as much power over the long run, as I think I am.

These are psychological and could be corrected by looking at a power meter, but:

3) I am weaker for aerobic power relative to short surges and recovery. I have about half a dozen short hills on one route, and taking them slowly in an easy gear I was torched on the last one. Probably at or over my threshold even at the slow pace. The next week I let it all out on the downhills, recovered going up and tried to power over (intending to burn up all my glycogen) and had about twice the speed over that section. I felt better after that than I had the previous week.

That might be accurately described as "I may have low FTP but at least I suck at climbing" but I prefer to think of it as a different mix of muscle fibers and not enough training on extended climbs. But I think it illustrates how climbing, depending on how you define a "climb", can be legitimately more tiring even with the same or lower power.

This is why a power meter is very helpful training on flat ground for climbing.

Climbing seems harder because the effort necessary to keep any sort of pace on a hill pushes you more than most people will push themselves on flat ground.

Given that you can't just ease up and coast on long climbs, you've got to train to produce contiuous power. Using a power meter on the flats lets you know exactly what you need to be putting out power wise, and helps you to push yourself to do so.

I have no scientific evidence, but I guess what I'm trying to say is that on a steep hill, your speed drops off faster due to gravity, compared to on the flats, so when you are climbing, torque is applied earlier during the pedal stroke, and maintained for a longer period of time to keep the speed up. On the flats, the wheels don't slow down as quickly, so you can apply all the torque over a smaller period of time to top off the speed you are trying to maintain.

Does the application of torque over the pedal stroke remain identical no matter what the terrain is?
Again I'm just thinking out loud, could be completely wrong. Feel free to school me.

Eseentially what you're saying is that you can take little rests on the flats without your speed dropping dramatically. That's true. However you can't do that and maintain the same power. If you want to produce the same power,at the same cadence, there's no way getting around the fact that you have to put in the same amount of torque for the same amount of time.


Which all gets back to my point that climbing seems harder because you have no choice (other than falling over) to produce a decent amount of power, whereas, you have to push yourself to go hard on the flats, and most people don't push themselves that hard.

ya you are right in saying that torque x cadence = power, but im wondering if that torque component is spread out over a longer period of time during the pedal stroke during a climb, which wouldnt affect the cadence or power.

doesn't the pioneer power meter, or garmin vector map exactly where torque is applied throughout the pedal stroke? it would be interesting to get someone to test this out and get some data.

not saying you are wrong, but power meter data would be hard to argue against.

Fortunately this has already been researched: https://www.americankinesiology.org/A...tItem/2413.pdf

i find eating a Thanksgiving dinner with my in-laws more tiring than walking a mile to a Dodgers game.

thanks for the info!

the paper noted that there are differences between 0-120 degrees, where on the incline more torque is applied during 0-120 degrees, and this is associated with a decrease in cadence. while the kinetics are not wildly different, it does change during the downstroke during a climb. its not just uniform increase in torque over the entire pedal stroke, so the pedal action is not identical comparing on a climb and on level ground.

The reason fatigue comes sooner for most people on climbs, despite power to the wheel being consistently a result of cadence x torque is because energy expended by itself does not equal torque. If a person expends more energy rocking back and forth, pushing the pedals at an ineffective angle, etc., while climbing, then less toque will be produced from the same amount of energy expended.

Another way of putting this is: if a power meter only measures torque and cadence, there are watts it is failing to measure. For most people, the watts spent NOT turning the cranks are higher while climbing than while pedaling efficiently on flats.

That's a hypothesis; so show me some data. How much energy is wasted through rocking? And given modern rigid soled shoes and fixed cleats, how does one push on the pedals at any angle other than the angle of the sole to the pedal?

It takes energy to keep pushing down on the pedal once it's already at the bottom, and if it's already at the bottom, it's not going to turn no matter how hard you press down. Likewise with any angle. It only turns if you aren't pushing (or pulling) parallel to the crank arm, and it turns most efficiently when pushed (or pulled) perpendicularly to the arm. This isn't a hypothesis, it's simple and observable by anyone at any time.

But until you put numbers to it (i.e., data) you could be talking 1%, 10%, or 0.00000001%. Just because you can name an effect, doesn't mean it's significant, which you are claiming it is.

The numbers are entirely dependent on HOW the individual pushes and pulls the end of the crank arm. 100% of the energy expended pushing the pedal down past the bottom and pulling it up past the top is wasted. Zero energy is wasted pushing the pedal straight down when the crank arm is parallel to the ground. Those who remember their trig functions can tell you how this varies at the angles in between.

For some people, there is no significant difference in wasted wattage in climbing vs flats because the energy they waste is essentially the same because their pedaling form - the torque they create with any given effort is consistent.

My guess is climbing because momentum is more negatively effected by gravity then wind resistance. You can coast for a much longer distance on the flats then a climb.