Ugly run yesterday

Ran 3 miles…14:44 out and 14:30 back for a total of 29:14.  The purpose was to run a nice even easy pace, just to help recondition my legs for running.  Well, The first mile and a half was okay, but I found myself laboring for the last mile and a half…all this was at a pace which should be moderately slow for me at this distance.  In fact my legs are still sore today…am I that out of shape? The temperature was probably in the mid 70s and it was humid…