Even though you seem to be staying mostly in the same place, you are indeed pushing your torso up and putting potential energy into it with each stride on an inclined treadmill. Just as much as you would with each stride on a hill with the same angle of inclination. The difference is that with the hill you just keep adding more and more potential as you go up while on the treadmill it keeps getting immediately leached back out between strides as your center of gravity shifts back down the incline of the treadmill. That energy is converted into a small amount of kinetic energy that makes it easier for the motor to turn the belt for that part of the cycle.
On a treadmill, you need to pick up your feet and move them forward, but once your foot is down you don't need to do anything to push your leg back, the treadmill is doing that work for you.
You also don't have to push your leg back while running normally, either, as momentum takes care of that for you. You can fall forward with very little effort; your torso is going to keep going forward while that foot is planted whether you push or not. The work is in keeping your torso off the ground and getting your other leg up there in time to take the weight of lifting your torso and keeping things going.
Unless we're talking about stair climbing. Then there's a lot more active pushing going on. But mostly up, not so much forward.
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On a treadmill, you need to pick up your feet and move them forward, but once your foot is down you don't need to do anything to push your leg back, the treadmill is doing that work for you.
You also don't have to push your leg back while running normally, either, as momentum takes care of that for you. You can fall forward with very little effort; your torso is going to keep going forward while that foot is planted whether you push or not.
You need to keep adding energy to that motion to maintain that velocity. The treadmill is doing that with electricity from outside your body. Maybe if the treadmill wasn't plugged in.....
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On a treadmill you are putting in that bit of energy needed to maintain forward momentum. It's just countered by the backwards motion of the treadmill.
You can test this by coming to a sudden stop on a moving treadmill and see what happens.
If the treadmill were doing anything to keep you moving "forward" then you'd fall off the other end.
Edited By TPRJones on 1446424185
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thibodeaux wrote:I'm about 90% convinced the only thing the incline does is make you lift your legs higher. A backpack wouldn't add any work to that.
I'm 90% convinced otherwise. Bet?
how do you prove it?
Yeah, I'm not sure. My first though is that you'd need something that measured center of gravity, and change thereof. Say, measuring where a person's belly button is at each incline setting. I would think that the higher incline would result in more variance in belly button height than the lower incline would, showing that the body itself is gaining/losing potential energy.
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thibodeaux wrote:I'd be satisfied with just measuring overall "effort" (whatever that is) in these two scenarios:
1. walking on an inclined treadmill
2. walking an equivalent distance on a ramp
make the angle the same, the surface as close (bouncy rubber, whatever) to minimize differences.
I don't think that answers your question though. I'm not arguing it's 1:1, I'm arguing that it's harder, and not just due to lifting your feet higher.
I think you'd have to measure energy output: 1) weighted (backpack) and 2) unweighted in different situations: a) standing, b) walking on no incline, c) walking on incline.
Miniturized walking robots, battery operated. A step counter. One inclined looped track, with an elevation reset in there somewhere. One on an inclined treadmill walking in place.
Run 100 batteries through each of them, until the battery is drained. Compare how many steps each robot took before its battery died. By the end one will have averaged more steps over the other... or not. Who knows. Old lady science... you gotta hold on tight. Whichever took fewer steps overall drained more battery with each step.
"Be bold, and mighty forces will come to your aid."
GORDON wrote:Miniturized walking robots, battery operated. A step counter. One inclined looped track, with an elevation reset in there somewhere. One on an inclined treadmill walking in place.
Run 100 batteries through each of them, until the battery is drained. Compare how many steps each robot took before its battery died. By the end one will have averaged more steps over the other... or not. Who knows. Old lady science... you gotta hold on tight. Whichever took fewer steps overall drained more battery with each step.
Problem with robots is that they are designed to walk a given way. The question is whether humans are adapting their gait to the surface in a way that is different than a true incline.
I can't think of any other way to measure the treadmill effort except by a set amount of energy consumed compared to how much work gets done. I don't know how to measure that in a human, so a small machine should be able to simulate it and you can measure batteries vs: work performed.
"Be bold, and mighty forces will come to your aid."
Reverse the problem. Hook the treadmills to a battery each. Get two dudes that weigh and walk the same. The treadmill that runs out of power first is doing more work for the person.
Diogenes of Sinope: "It is not that I am mad, it is only that my head is different from yours."
Arnold Judas Rimmer, BSC, SSC: "Better dead than smeg."
GORDON wrote:I can't think of any other way to measure the treadmill effort except by a set amount of energy consumed compared to how much work gets done. I don't know how to measure that in a human, so a small machine should be able to simulate it and you can measure batteries vs: work performed.
