I would be interested in a free sample (duh? of course).
I have read that training with O2 on the shorter, higher intensity runs- benefits the longer runs.
I am trying a different training regimen for my endurance running. My new training is going to drop a lot of miles in favor of tempo and interval training. These are the days O2 would be beneficial. The idea is that less junk miles and more quality training with still a long day will improve times and decrease injuries. I feel your O2 would be a beneficial supplement for my new training.
Let me know. I would, of course, log it here at EF.