Treadmill training - why incline instead of faster pace?

I just came here tonight to ask a similar question. I do not get the 1% incline thing. I've run the same paces outside vs. inside (at 0%) and sometimes it feels easier outside. The "wind" blows both ways, hills go up and down (and flat on the track), so I do not think there should be an adjustment made when running on a treadmill. Some might argue that the "ground" (belt) is moving, but you are staying in one place. Yes, it would make a difference if you were moving forward (like on those moving sidewalks at the airport), but not on a treadmill where you are running in place.

The air resistance outdoors would allow you to lean slightly forward when running, so the angle your leg makes with the ground when you land would be slightly different outside vs. flat treadmill. The 1% incline or whatever it is would mimic this different landing angle... or to think of it another way, gravity would be forcing you slightly backwards (with respect to the treadmill belt), rather than the air resistance. It does not really matter though.

Haha seems legit

Even if two efforts are equivalent in magnitude, that does not make them equal in terms of the stress they impose on the body. Runners tend to use a bit different muscle set on treadmill due to the moving belt, using quads more - somewhat akin to how someone would run downhill. Thus, while running faster would be higher effort using the wrong muscles. Setting incline promotes use of "regular" running muscles, i.e. glutes.

Air resistance may or may not be a factor, depending on how fast you're going, and what the wind is like outside (rarely is air completely still like inside).

2 reasons: Its less pounding on the body to make a run harder by inclining a treadmill than increasing speed. Back in the day a lot of treadmills didn't go faster than 10 mph or so. So you're at the treadmills top speed and then what do you do... Its carried over.

And 2+2=pear.

Where do you hang out now?

counterpoint: http://www.active.com/running/Articles/Equating-Treadmill-and-Outdoor-Running.htm