Home Forums Hunting & Shooting Hunter's Campfire Physics Question

Thanks - see my first post on this thread.

Hard to believe that there has not been a dyno test on pedal power to determine the best stroking technique to produce the best/most torque..............

We used to call chicks built like that "thunder thighs"... 🤣

Hmmmmm. On the surface, that example doesn't cause me as much dissonance.

It also helps that you are spreading the workload over more muscles. I used to ride distances and it helps. It also helps to alternate legs and ride with only one foot clipped in. You'd be surprised at the speed that you can keep up for short distances. I used to ride a 1/10 of a mile with each foot alternating for at least a mile, total.

Just me , but I'm thinkin' either one will only enhance the 'road-rash' on the knees when ya take a dump...

More power to ya, PB... But I gave up bicycles about one second after I got my drivers' license.. Ride safe, sir..

a great site to post this question is : https://physics.stackexchange.com/

There are a number of tests that have been done. Most of it shows that there is no power added on the upstroke in most riding conditions.

https://www.google.com/search?q=cli...327j0j4&sourceid=chrome&ie=UTF-8


https://www.bikejames.com/strength/why-pulling-up-doesnt-add-to-your-pedal-stroke-power/

This is a comment from one of the links.


"Research has shown that even if you think you're pulling up on the upstroke, you're not. The pedal is actually pushing your foot up via the force created by your opposite leg pushing down."

That's where this question enters my mind. If you were able to apply a greater force on the upstroke than the downstroke, then wouldn't you just be dragging the downstroke leg down with the greater force of the upstroke?

I'm certain USA Cycling has researched all aspects of bicycle riding and racing.

Thanks for the well wishes. I am a courteous and alert rider. When we take to the streets, irrespective of our manner of transport, we assume risk. When you look at bicycle fatality data, you immediately identify what you can do to reduce risk. Don't ride drunk or impaired. Don't ride at night without lights. Don't ride against traffic. Don't ride on sidewalks. Those things alone cut the risk in half. I take other measures to reduce the risk to a level that is acceptable to me on the roads I ride on. Even then, all it takes is one texting motorist and my number is up.

Mine were very flattened side to side, just very deep...

Reading thru for the first time and I could not wait to get to the last post to chip in, but 5sdad brought up the the lug wrench example for me.

I think that alternating pulling/pushing and pushing/ pulling simultaneously with 2 legs would require just the opposite forces with 2 arms.
I think it would take a lot of training to keep the upward force from detracting from the downward force for a net increase of torque.
Sounds like a lot of work to me. Heck I got a work out just reading thru this.

Also, torque does not care if you are going uphill, down hill or upside down.

I am not a bike racer, but am a spinning instructor, part of the course to be certified is the kinematics of the whole system, and how to address it and strengthen it with drills during a spinning class.

There are not opposing forces, you can make the pedals go round with either foot, you are turning a crank, so using both feet is additive. Proper riding technique is not really a pull up/push down pattern, but to use the full 360 degrees of crank, you have more power potential at different points depending on the part of the cycle. Top riders use the full 360 degrees of power.

This is why it's faster, in most cases, for a rider to stay in the seat and power through it. It does pay benefits to stand and pedal, where you can get some benefit of the full power stroke, but on the down part you are adding your body weight to the crank. While standing it's MUCH harder to do more than the push down portion of the cycle, but with the added force of body weight, it's a good tradeoff under heaviest of loads (also a way to give some muscles a short break).

If you watch top riders, the upper body doesn't move, this shows they are using full cyclical force. When you start to loose form and go more to the "push down" model, the upper body starts to sway to get more leverage for the push, once that happens you can't really get full 360 degrees of force of either leg.

Being clipped in helps!

I routinely will have a spinning class pedal only with 25% of the cycle and focus on just that, so for 30 seconds you ONLY apply pressure on down stroke (call in 1 to 5 oclock), then the upstroke only (7 to 10), then the "over the top (10-2) and finally the "across the bottom" (5 to 7).

Uses very different muscles in each group.

Depends on where I am at any particular time of the year, but mostly pretty flat I suppose.

An explanation in a bit more detail might help. Torque is simply a twisting force that makes something rotate, which is different from the linear or up/down force the OP mentioned in the original question. A basic calculation for torque is a liner force x how far away from the axis of rotation the linear force is applied.

When you sit on a bike and pedal, you are turning the spindle the crank arms are attached to, which is generating a twisting force that makes the spindle rotate. The torque equation applied to pedaling a bike is: linear force (pushing on pedals) x crank length. The direction of the force of the pedal going up and the pedal going down are in the same rotational direction when seen from the spindle, so the both add to the total torque. The OP's description of the pedal going up and the pedal going down cancelling each other would be analogous to rotating the two pedals in opposite directions (one clockwise, the other counterclockwise). But both pedals are moved in the clockwise direction when seen from the right side of the bike, so the pedal forces add to each other.

Yes, but only if the downstroke leg was doing nothing, which in any practical sense is never. The downstroke leg is contributing and additive to the upstroke.

I think from a strictly mechanical perspective, only pushing down your force is limited by your weight (assuming you are not resisting uplift by holding yourself on the bike). Push hard enough and you rise from the seat. Pulling is not limited by your weight, as the bike seat/frame/tires/ground resists the force you apply. Thus, I believe it is possible from a mechanical perspective that pulling can conceivable transfer more torque than pushing, assuming your legs could do it. Practical, I believe pushing is much more efficient for a human body. When you do it together, some of the uplifting force from the push can be resisted by the downward force generated by the pull. By pushing and pulling, it is possible to make the down more efficient by providing resistance to uplift. At least in theory.