I finally got back to the gym and have experienced a familiar uncomfortable sensation while on the treadmill. I tried to challenge myself (the PE teacher at the school where I teach calls them 2-n-1's, where you walk for 2 min and run for 1) and it felt great - except for this sensation.
What happens is my legs feel like they are being stuck by a million needles. It is very uncomfortable - I actually had to get off the treadmill and stretch for a bit (which helped, btw, but I couldn't get back on the treadmill). I didn't feel this when on the elliptical....
Any ideas?