Ok, it took a week to get to the experiment, and i didn't have my video camera, but here is (roughly) how it went.
I know a guy who runs wicked fast. like 6 minute miles in a 10k fast. So when i found this entry online by Jessi Stensland, I had to try it. I think one of the main keys is having someone who can do 10mph running next to you with no effort.
So, warm-up, 6mph for a bit. no sweat, that is my pace! My friend was almost looking frustrated at the slowness of it.
Interval at 7 mph. This took a little effort for me, but was not too bad. 1 minute was a short enough time to not get pooped. then a walking rest.
Interval at 7.5mph. Still not too bad. It helped having someone go effortless right next to me. Kinda made me relax to look over and see that he was having such an easy time with it. then a walking rest.
Interval at 8 mph. Here is where my running buddy noticed that my hands were too low. I thought I had my elbows at 90 degrees, but he said they started at below 90 degrees and fell down from there. This was essentially putting on my brakes and taking way tons of energy to keep going. I decided to focus on arm position for the rest of the intervals. walking rest.
Interval at 8mph. This one was focusing on my arm position and the effort on this one was not too bad. I could tell i was going fast, but in the minute+ that i held this speed, i did not really get out of breath too bad, and was not getting overly tired. I am going to be sore tomorrow.
Interval at 8.5 mph. This seemed not so much faster than the 8. I held the speed, and with him running effortlessly next to me, I tried to be effortless too. I kept dropping my hands, and at this speed i could really tell.
Interval at 9mph. Wheee! this was fast! Elbows have to stay at above 90 degrees or I was going to fall off of the treadmill! Stay light, Stay forward, stay balanced, and keep my arms UP! Old people all around us are looking at us like we are nuts. 1.5 or so minutes at 9mph. walking rest.
Interval at 8mph. This was just to see how it felt. I have to say, this felt much easier - not as easy as 6mph, but a lot easier than 8mph would feel like before. My friend called it "resetting your easy button." True-dat.
I think that at the faster intervals i had some balance problems. Those may be core strength issues, or just that I need more practice at that speed. Either way, I need to practice and get core strength up. I also need to keep my arms bent more than I have been. This saved SO MUCH energy, I was surprised. Amazing to think that my arm position could have been keeping me slow for so long.
If you do this experiment, be careful. Treadmills are scary, and should be used with caution. Don't base your experiment on my blog, or I will have to come up with some sort of waiver of liability. Base your experiment on the link above. She is a professional.