What it takes
A sub 3:45 marathon means holding 5:19 per km (8:34 per mile) from start to finish. In Jack Daniels' VDOT model, that is a fitness score of about 41.0.
The marathon pace chart has the splits for it. It also covers every other time from 2:30 to 6:00.
One consistent block of training usually moves a runner a couple of points. So this plan suits someone who runs the marathon in about 3:54:27 today.
Easy, threshold and interval paces come from that starting point, not from the goal, so you train at the fitness you have.
Sub 3:45: keep the easy days easy
Sub 3:45 is 5:19 per km (8:34 per mile). Your easy running starts at 6:14 to 6:32 per km, at least 55 seconds per km slower than goal pace. Protect that gap.
The usual mistake at this level is easy days that drift towards marathon pace. It feels productive, but it leaves you tired for the sessions that count: the threshold runs and the marathon pace runs on Tuesdays. If in doubt, run the slow end of the range.
At 6:32 per km, the longest run here, 27.5 km, takes about 3 hours. Race day is about 45 minutes longer than that, so the marathon pace finish to the long run and your gel practice are what prepare you for the last hour.
Your training paces
Set from a 3:54:27 marathon, the fitness this plan starts from.
| Pace | What it is for | Per km |
|---|---|---|
| Easy and long | Most of your running. | 6:14-6:32 |
| Threshold | Tempo runs. Comfortably hard. | 5:12 |
| Intervals | Hard repeats with recovery. | 4:47 |
| Marathon pace | Your goal pace. Every marathon pace session uses it. | 5:19 |
The VDOT chart has the full set, repetition pace included.
The plan, week by week
4 running days a week, peaking at about 62 km. Every fourth week is easier, and a taper leads into race day.
Long runs are on Sunday. Hard sessions are on Tuesday.