I got the shirt from Five Below. Not sure if that chain is everywhere or not. It's a trendy dollar store... everything there is five bucks or below.
About the hills/running/etc question...
I can answer the basic "What did I do?" question. I have doubts as to whether I can answer the deeper "Why did it work?" question. There may be too many independent factors in my case to pin my success down to one thing. I do think adding incline treadmill walking aka "hills" is a fantastic idea and potentially a major key to unlocking success.
My regimen prior to my little running... - I had done about 6 workouts of super slow "hill" walking at 2 mph and 7.5% incline. This was in addition to my normal 25 min of elliptical and 25 min of "fast" treadmill walking at 3.2mph.
Other factors that may have lead to my momentary success...
By far my biggest issue is tight calves. I had done weight lifting focusing on my legs just prior. This included a pretty decent warm up. That warm up was likely instrumental - I did 100 alternating leg step ups.
Also after an intense week of logging lots of cardio minutes I had a day off with no cardio the day before, so my legs were rested.
For the 2 months prior to my little interval running outburst I have been doing 2 cardio things: 25 minutes elliptical and 25 minutes treadmill walking as fast as possible about 5 times a week. I have recently added in more weight lifting.
Not sure if this helps. Please feel free to ask me more questions.