![]() ![]() Notice that you are not moving forward but you are expending a lot of energy. Deleteīoth walking and running are so very inefficient as means of moving the human body forward that you can't readily assume basic physics will give you the correct answer. If you are going downhill, you will have less of an Fnet due to the direction of gravity (switching from positive to negative). As you increase in slope, your Fnet increases due to the gravity equation, as you accelerate for reasons other than gravity, your Fnet will increase, and if your velocity increases, your Fnet will slightly increase due to friction. In addition, your frictional losses and resistances are dependent on your velocity, so that will increase as well. If you're actually physically putting work in to accelerate or decelerate, then that will increase or decrease. If we assume constant velocity, your body is actually not accelerating, so F walking drops out. The sin function is in there due to trigonometry, which is difficult to explain if you have never learned it, but it has to do with angles and triangles. Inversely, gravity helps you out as you're going downhill, so the g becomes positive, thus less work required. As your angle increases, the force of gravity increases. Gravity is where your incline comes into play. It works in the opposite direction of your movement, so we will denote this as g. an object in motion tends to stay in motion.)įnet = F gravity + F walking + F other resistances such as friction and wind resistanceĪcceleration due to gravity is g (9.81 m/s^2). So, to wrap things up, we can go through the math.Īt constant velocity, your forces balance out (Newton's law. So, the force of gravity plays a massive factor.Īlso, your frictional loss and other resistances tend to be functions of your velocity, so the faster you walk, the more you have to overcome to stay at a constant velocity. In addition, your fighting gravity more directly as you climb in elevation. Since the angle decreases how much the ground absorbs your acceleration, you have to balance that out with other forces, such as more work done by your hike. The force of gravity needs to be "fought" more as your angle of climb changes, because you have less ground to rebound your acceleration (for every action, there is an equal but opposite reaction). Gravitational acceleration is constant, BUT the angle you are climbing changes how you fight this force. The energy used, on the other hand, increases as you apply this force for a distance (hence force x distance). At constant velocity, your forces balance out to zero. If you do a force balance and determine the net force working on you as you climb, you have to consider a few forces.įorce of gravity, force of friction, and the force you apply as you climb. The equation, W = F * D, is dependent on your velocity and the angle of your climb, and here is why.į = m * a, m = mass, a=acceleration. ![]() I am an engineer, so I'll clear this up for you guys. ![]() Summitpost discussion / debate on the topic Even though this isn't the best assumption (probably more work descending 20% grade than flat, but less at 10%), it's probably a decent guess until I get a lot of data collected. ![]() For now, I am going to assume that one mile downhill (at any grade) is equivalent to walking a flat mile. The study & equation I used did the research on a treadmill, where friction on downhill is quite consistent and this is not the case in reality. UPDATE #1: I think generally we all feel the downhill could be quite underestimated. I personally would trust the uphill estimates pretty well, but the downhill may be underestimated. In that case, you might want to scale the energy by some factor - say 1.1 (10% increase), but this is highly speculative. (I have disabled the 'terrain' option for now and set it at 1) Basically this is a rough estimate of the workload and calories burned during a hike.įor terrain, assume a value of 1 unless you have a feeling that the terrain you are hiking on really adds on more work that normal. Some background is explained in this post. Terrain Scaling (1-2, normal to all very rough) The most accurate personalized calculator for calories burned during hiking. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |