At least, it felt good when I got back to my cool down run :-)
Meant to do 12 x 400's (quarter miles), and only managed 10, as I lost count, and number 9 was weak.
In order to get to the training program for a half marathon at 1:33:30, which seems to be what I need to do in order to start the training program for the 3:15 marathon - the Boston qualifying time, I need to be doing a 5k pace at about 20 minutes, which is 6:26 per mile, or 1:37 per quarter, and I came close to that today, sometimes!
Here's the ragged training record.
Oh, and here's the book I am using to put all of this together