Wow, about 60 replies to a grown person trying to improve on a 19:40 5k.
Does he really need all your advice about mileage, percentage increases, steady-state pace, tempos, innovative hill sprint techniques, periodization, tapering, long-intervals in the middle of winter ... and my favorite "speedwork" and "sharpening".
When did America get so f***ing soft? You guys are making a classic mountain out of a molehill.
If he ran 17:XX some years ago, then he knows how to get there. I was never a fan of reading a plan out of a book and following it, but I tell you one thing: that is probably the only appraoch I will guarantee is better than reading a plan off of letsrun and following it. Buy a book from Pfitzinger or Daniels or best of all Tony Benson and follow it blindly if that is your cup of tea. Or if you like obsessing about pace and intervals and such buy Joe Vigil's book and go to it.
Running a 16:30 5k doesn't require complicated plans or formulae or perfect training unless you are a girl or really have poor talent. You don't need a 25 week base period either.
That advice about improving your sprinting was hilarious. Like getting down to 26 for the 200 is going to make those 39.6 200's much easier.
I read Benson's book long after I had experimented on myself and my between track and between XC training, and all I found out was that I was doing things right on my own and with the little bit I learned through Lydiard books and trial and error.
Once racing is over (October?) Benson recommends a short rest, then gradually building miles (Nov-Dec) which might be 30-40-50 for you. Then the Base period (Jan-Feb-Mar) which gets more specific and higher mileage and you are pushing yourself now. This might be 50-60-70 for a 16:XX guy. Then there is a Preparation period that consists of a 5k specific intervals and a 7.5 or 10-mile tempo run and 10 minutes of sprints each week and a long run.
Please stop telling this guy that he needs to raise his mielage 2 miles a week, and to buikld to 80 mpw or 100 mpw. He doesn't need to be running 12 miles a day to run 16:30 and he doesn't need to start doubles until he is running a solid 60 mpw, and once he is running that I think a 16:30 5k wwill take care of itself.