I'm just a rec runner but have always enjoyed doing speed work more than continuous runs at a easy or moderate pace. I have done Tabata Intervals, tempo runs and the usual 10X400, 5X800...etc. Weather here can get really crappy in the winter so I do some of my runs on a treadmill. Would a workout starting at an easy pace and increasing pace every minute by .1 mph until I can't physically continue be of much value? I am guessing the accumulated time would be somewhere around 30 minutes although the accumulated fatigue may make it less than that. Thoughts?