How to mimic hills running on treadmill?

I am thinking about following one of Hal Higdon's programs, which includes hills. Unfortunately, Hal's definition of "hill" is very vague. Because there are no hills where I currently live, I am using a treadmill. I can set up to 15 degrees of incline. Currently I am running several repeats of the following: running up a 9 degree incline for 4-6 minutes, followed by 3-4 minutes of running at the same speed at zero incline. Does this make sense?

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Personally, I don't think you can really do hills on a treadmill as you don't have to lift your body through a vertical distance. Do you have access to any tall buildings with stairs? – rthsyjh Dec 18 '13 at 14:23
That's a fallacy, @Jaydee. It's the same fallacy that is behind the statement "Running on a treadmill is easier because the belt moves backwards for you". I don't get into the physics enough to be able to explain it coherently, however. – JohnP Feb 6 '14 at 18:34
I doubt it is a fallacy. My physics is pretty good and if you aren't lifting your mass out of the gravity well, you are expending less energy. – rthsyjh Feb 7 '14 at 13:13
[Sorry, got locked out while editing.] The idea of the incline is that you lift yourself as you step forward and then drop down as the belt carries you back, but in practice people tend to keep their head height about the same through out the stride so you don't get the same benefit. – rthsyjh Feb 7 '14 at 13:19
I'm not saying there is no benefit to running on an inclined running machine, bu think about this. Take a bike on a turbo trainer on the flat, then lift the front wheel so the bike is on a 3o degree incline. Is there any difference in work required? – rthsyjh Feb 7 '14 at 13:35