Hi Frances,

If you follow a periodization philosophy such as:

1. aerobic base 12-16 weeks

2. anaerobic phase (or racing)

3. racing

then you can do the first 5 weeks of his plan as the last 5 weeks of your 12-16 week base period, with everything as MAF runs, then start the racing in the 6th week. He only has 3 races over a 7 week period, spaced 3 weeks apart. You could  do a few fartlek workouts in between races, with the rest of the runs being MAF runs.

If you don't periodize then you can just pick up the schedule as is, doing all the runs at MAF, except for the races. Or throw some fartlek or an LT run in once a week--whatever it is you like to do for anaerobic work.

Then there is always the option to just MAF the whole thing, without races, all the way up to the half marathon. Making his schedule an MAF base period with the half marathon being the start of a race season. Just do every workout at MAF or below.

--Jimmy