Anatomy of my half marathon PRs

When I run the Oklahoma City Half Marathon Sunday, I'll be trying to shave six minutes off my PR for a guaranteed entry into the New York City Marathon this fall.

Six minutes seems like a lot, especially since my last half marathon was only three months ago. But I've had a bigger improvement between half marathons before, knocking off nearly 10 minutes from a half marathon I ran in Jan. 2008 to one I ran last November.

Here is a little chart of the half marathons I've run

Date...................Time...............Pace................Time shaved from last Half
12/10/06.........1:54:05............8:42
11/04/07.........1:52:22............8:35..................1:43
01/27/08.........1:48:43............8:18..................3:39
11/02/08.........1:38:59............7:33..................9:44
01/31/09.........1:36:01............7:20..................2:58
Sunday ?????