Oh, I have that same problem. When I get out in the fresh air, my first instincts are, I want to run..but the back of my calves always burn, and it's one thing to burn when I'm running (I assume because I weigh so much,and I'm not used to it), but I think it's another for it to go on for a ridiculous amount of time. However, I've found that sometimes walking it off works.