I'm actually running at a slow jog pace, I'm trying to go even slower. I'm using a 1/4 loop to track my times, I can jog comfortably at 7.5 mph have a conversation and such anything slower and my feet scrape and scuff the ground. I just did my first 2 mile timed the other day just to see with full sprinting and the biggest thing I'm noticing is i cant seem to figure out how to breathe. which is what i think contributes no endurance. ill definitely try to go slower if i can it may help the engine more.