[QUOTE=deanc2000]
I have used treadmills for running on for YEARS. I always run at a 2 slope, though, b/c with the treadmill being perfectly horizontal, there’s that GIVE with every footfall, which actually brings the track to below horizontal for a split second. I think this factor may also explain why treadmills SEEM easier than running on the street, ie on a treadmill at 0 slope, you are actually running slightly down hill because of the GIVE of most treadmills.
So run on a 1 or 2 slope and this will take out this factor. I think running on a treadmill with a slope could actually make it harder than running on the street, but safer b/c of the give of treadmills.
Anyone want to comment?
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Physics wise, I agree with Mangetout and Alex_Dubinsky.
However, for long (40 mins +) steady state runs, I think running on a treadmill is more difficult than running outside on a clear day. I think running on 0 slope is near equivalent to running a bit downhill. So, I run on a 1 or 1.5 to simulate outside conditions, i.e. even on a clear day there will be slight wind, some uphills and downhills, etc. However, running inside on the treadmill, one must be consistent with the pace. Outside, I can deviate a bit: slow down a little bit into the wind and uphill, recover on the flats, and pour on some speed (even if I don’t personally realize it) when I’m going downhill or when I’m wind-aided. It’s with those factors that I find it easier to run outside and have better times overall, because inside even without those factors working against me, I’m still running on a slope upwards, and trying to meet that pace consistently gets very tiring as time draws on.