I've been tread milling it for 2.5 months now for 1/2 of my workout sessions. The other 1/2 is outdoors. I can say TM running is way different.
I'd say keep an incline to keep your endurance up. And I've added .30 to my 5K runs on the treadmill. So I'm actually running for 3.4miles. I do feel there is an error factor on the TM. I find it's consistent, least in running and DW's too, but the actual mileage is where I am concerned. YES I see the same miles and time per run – but it is not the same as the outdoor runs. Hope that makes sense. I’d be more worried if I saw inconsistent TM runs where my times fluctuated and the mileage did to for the same time frame of my runs.
Somewhere in JG's book he does mention to add 10% to your run for TM workouts. And personally I run and walk faster than what he wants when I switch his app too indoors/treadmill. BUT I also see that with my monitoring devices - Nike+ stuff that my time/pace is SLOWER on the TM vs. outdoors when I use the same equipment. AND I’m WAY WAY more tired after a TM workout vs. an outdoor workout. I think it’s due to being able to use the GPS on my Nike watch outdoors vs. the shoe pod only method on the TM far as actual data collections. AND I’m sure the physics and momentum of outdoor running makes us faster too vs. the TM. I've been in contact with Nike and they say none of their equipment is really approved for TM use. It is 10% accurate. Seems that's the out...+/- 10% accuracy. ;) Again, I do see consistency in my TM runs – run after run. And I see FASTER GPS times and consistency in my runs – run after run outdoors as well – so I feel I’ve got a great bench point/mark.
Sorry to ramble. I run on the TM with a 7 incline to keep me working hard during my workouts. Is that extreme? Not sure...but I just want to make sure I don't lose my edge/conditioning while the weather is getting bad in PA and I have to use the TM 100% for my runs. Did I start at 7? NO it was 3 and I’ve worked up to 7 for the whole workout. Just as my speed has increased as well for both my interval runs and walk.
I would not make too many changes at once. When DW started and I did on the TM we were beating ourselves up with poor results and not feeling the fun of the run. Now we have made little tweaks - like adding some incline a little per week. Then next week we try and speed up our mph on the speed settings of the TM - while still keeping within our comfort zone/ability to not get injured. So far we are doing well. It's just a bit different indoors on the TM. I'm glad to see my outdoor runs have stayed the same if not improved a little during this same time frame too. That way I see I'm not losing ground in my conditioning - literally! :)
GOOD LUCK, hope some of this is helpful.
How about the rest of the runners? Any suggestions on TM running?