[michael1]

Has anyone computed the force applied at the pedal (relative to bodyweight) from power meter data? Given the need to pull on the handlebar I would suspect >1x bodyweight might occur.

Would be curious to know peak value and how it rises and falls each cycle to compare to something like uphill running or hiking. I imagine this is relevant to anyone that does a foot-based sport and wants to get a better understanding of cross-training effects. My thinking is that road miles for base training plus singlespeeding might have high carryover to hiking up mountains.

 

[coleam]

The biggest issue with using singlespeed riding (or any form of biking) as cross-training for hiking is that it uses different muscle groups. It'll help you build a solid cardio/aerobic base, but the muscular training won't do very much. I used to hike a lot more than I do now, and despite my greatly increased biking load, I'm not nearly as strong a hiker as I was ten years ago.

 

[solo-x]

You're gonna need a little more detail than that. At what power @ what rpm? 350w @ 35rpm is ~95Nm. With a 170mm crank arm, that works out to 126lbs if I've done my math close to right. That doesn't seem in the "pull on bars" range for a 170lb rider though. 750w @ 35rpm gets us up around 270lbs of force. I can squat 2.5x's my body weight, so theoretical one legged squat would be 225lbs of force that a single leg can put out. I've thrown down 1200w (for very short periods of time in a race) and [email protected] works out to ~233lbs of force. Those numbers seem realistic to me and with the help of adrenaline I can see how I'd be able to do that with an even slightly lower cadence.

Body weight work like hiking isn't going to help max force, but it will help endurance. Single speed work will help max force, but you rarely need that in a hiking setting. And hitting the gym with some low rep/high weight squat work will do more for that then an SS ride will.

 

[WillTheGreat]

You're gonna need a little more detail than that. At what power @ what rpm? 350w @ 35rpm is ~95Nm. With a 170mm crank arm, that works out to 126lbs if I've done my math close to right. That doesn't seem in the "pull on bars" range for a 170lb rider though. 750w @ 35rpm gets us up around 270lbs of force. I can squat 2.5x's my body weight, so theoretical one legged squat would be 225lbs of force that a single leg can put out. I've thrown down 1200w (for very short periods of time in a race) and [email protected] works out to ~233lbs of force. Those numbers seem realistic to me and with the help of adrenaline I can see how I'd be able to do that with an even slightly lower cadence.

Note that these pedaling force calculations are the 'average effective pedal force' which will be considerably lower than the peak force applied to the pedal. The 'effective pedal force' means only the force applied perpendicular to the crankarm, so even if you stand with all of your weight on the pedal your 'effective force' is zero when the crankarm is at the 12:00 and 6:00 position. At the 3:00 position your pedal force and effective force will be equal, and your peak effective force will be near this position.

Because the effective force is nearly zero at 12:00 and 6:00, the 'average effective force' is lower than the peak effective force. And since the effective force neglects pedal forces that are not perpendicular to the crank arm, the average pedal force will be higher than the average effective pedal force.

Another way to illustrate this is if the 170 lbs rider is riding in a standing position producing 350W at 35 RPM, we know he must be producing an average pedal force of at least his body weight or he would fall back to a seated position. Of course the average effective force is only 126 lbs, but that is because much of the force on the pedal is ineffective for producing crankarm torque.

I guess this is a long-winded way of saying that the data produced by power meters isn't going to be very useful to answer the OP's question because the forces calculated don't fully represent the force the rider is producing in a way that is comparable to hiking. What might be useful would be pedal-based force/power sensors with high-speed sampling instead of averaged power.

 

[eri]

I think the force is pretty high relative to body weight. 2x?

A squat requires a big bend to the knee but grunting singlespeed i keep my leg pretty straight and my falling bodyweight plus handlebar pull plus upstroke on other foot adds up.

I time my weight fall so peak force is right when crank is parallel to the ground, that breif pump propels me until i do the same with other foot.

Try and hop to apply max force to a scale with one foot, you should easily be able to drive it way past any number that you can squat, so long as you dont bend your knee to far.

 

[solo-x]

Note that these pedaling force calculations are the 'average effective pedal force' which will be considerably lower than the peak force applied to the pedal. The 'effective pedal force' means only the force applied perpendicular to the crankarm, so even if you stand with all of your weight on the pedal your 'effective force' is zero when the crankarm is at the 12:00 and 6:00 position. At the 3:00 position your pedal force and effective force will be equal, and your peak effective force will be near this position.

Because the effective force is nearly zero at 12:00 and 6:00, the 'average effective force' is lower than the peak effective force. And since the effective force neglects pedal forces that are not perpendicular to the crank arm, the average pedal force will be higher than the average effective pedal force.

Another way to illustrate this is if the 170 lbs rider is riding in a standing position producing 350W at 35 RPM, we know he must be producing an average pedal force of at least his body weight or he would fall back to a seated position. Of course the average effective force is only 126 lbs, but that is because much of the force on the pedal is ineffective for producing crankarm torque.

I guess this is a long-winded way of saying that the data produced by power meters isn't going to be very useful to answer the OP's question because the forces calculated don't fully represent the force the rider is producing in a way that is comparable to hiking. What might be useful would be pedal-based force/power sensors with high-speed sampling instead of averaged power.

Excellent post. You are correct, I neglected to take into account avg force vs. instantaneous. At any rate, I agree with the final assessment.