4mi. So just leave the front door and time a 2 mile out and back sprint? This was fun the last two weeks in lieu of the bridge run, and I believe this familiarization with the breathing and lungs necessary to do well in a 5k like event. I did 26:01 this week, negative split on the 13:16 it took me to get to the back of the neighborhood gate. I’ll put more of these in my schedule!