Hi Bunbun:
When I go for max speed, I have the incline on zero or 1. When I am doing intervals, I put the incline on 15, the max the treadmills at a local fitness centre offer. I will then drop the speed to between 4 and 4.2 mph. It is tough. It feels like the hiking I have done in the Pyrenees, just straight up with a heavy backpack, all along the switch backs and take no breaks! The mileage tracker on the display monitor shows a lap as a quarter of a mile (I don't know if this is standard, this is the only treadmill I have ever used), so I use this as my interval segment and keep going with the interval for the full quarter of a mile distance, about 3 mins. After this, I will do a 2 min recovery walk at a max of 4.6. I play a psychological game with myself, trying not to keep checking the distance-covered tracker but focussing on setting a rhythm with my feet and keeping a steady breathing pattern, that's how I keep myself challenged, on track, and going the distance throughout the full interval.
I power walk at the moment about 4 times a week. My kids are members of our local YMCA in Ann Arbor, a fabulously top of the range refurbished facility and when I take them to swim, I go to the top floor where they have a running track while they leap about in the water and then we are all happy. I speed walk 6 miles there, which I have completed in 60 mins. I was so happy! I do this twice per week as my steady state cardio, and then the other two times I do the intervals at a different fitness centre when I am either on my own or the girls are using the ice skating rink there. I pretty much have to fit my activities around the girls at the moment. Once they start school again after the break, I will be able to add in Cathe's again.
I just had to buy anew pair of runnimng sneakers today as I had worn out and totally broken down my old pair. I had had them for 5 years! Terrible. So, I am hoping to improve my speed walking even more with all this improved cushioning and zip!
Keep me posted, let me know about your progress, any good training routine you have set up for yourself.
See ya,
Clare