20-Week Marathon Training
A longer, gentler build for newer runners or ambitious goals.
- Written by
- YourMarathonPace
- Published
- 9 November 2026
This guide is general information, not medical or coaching advice. It has not yet been reviewed by a qualified coach. Speak to a doctor before starting a new training programme, especially if you have a health condition or injury.
Who benefits from 20 weeks
A 20-week plan suits newer runners, people coming back after a break, older runners who need more recovery, and anyone chasing a big improvement. The extra time lets you build up more gently.
Extra base phase
The first four to six weeks are mostly easy running to build the habit, strengthen your legs and grow the long run without rushing. Strength work two times a week fits well here.
Managing load
Longer plans make it easier to avoid big week-to-week jumps in mileage, which are linked to a higher risk of injury. Use the extra weeks for recovery weeks and as a buffer if you get ill, rather than adding more hard sessions.
Taper
Most plans cut weekly mileage over the final two to three weeks while keeping a little running at goal pace, so your legs stay sharp. Expect to feel restless or sluggish during the taper. That's normal, and it isn't a sign you've lost fitness. Don't try to make up missed sessions in race week.
Sources
- The training–injury prevention paradox: should athletes be training smarter and harder? — British Journal of Sports Medicine (Gabbett, 2016)
- The effectiveness of exercise interventions to prevent sports injuries — British Journal of Sports Medicine (Lauersen et al., 2014)
This guide is general information, not medical or coaching advice. It has not yet been reviewed by a qualified coach. Speak to a doctor before starting a new training programme, especially if you have a health condition or injury.