What it takes
A sub 20 minute 5K means holding 3:59 per km (6:25 per mile) from start to finish. In Jack Daniels' VDOT model, that is a fitness score of about 49.9.
The 5K pace chart has the splits for it. It also covers every other time from 14 to 45 minutes.
One consistent block of training usually moves a runner a couple of points. So this plan suits someone who runs the 5K in about 20:53 today.
Easy, threshold and interval paces come from that starting point, not from the goal, so you train at the fitness you have.
Sub 20 is built on volume
At 3:59 per km, a sub 20 5K is fast, but most of the race is still run on aerobic fitness. That is why this sample runs five days a week and climbs to 51 km, with a Sunday run of up to 14 km. More easy running is what lets you hold the pace through the third and fourth kilometres.
The faster work comes in layers. Hill repeats in the base weeks, then short 200 m reps at 3:50 per km for speed, threshold at 4:27, and 800 m reps at 4:05 in the peak weeks. Two hard days a week at most, with easy running between them.
Your training paces
Set from a 20:53 5K, the fitness this plan starts from.
| Pace | What it is for | Per km |
|---|---|---|
| Easy and long | Most of your running. | 5:21-5:36 |
| Threshold | Tempo runs. Comfortably hard. | 4:27 |
| Intervals | Hard repeats with recovery. | 4:05 |
The VDOT chart has the full set, repetition pace included.
The plan, week by week
5 running days a week, peaking at about 51 km. Week 5 is easier, and a taper leads into race day.
Long runs are on Sunday. Hard sessions are on Tuesday and Thursday, never back to back.