Training Plan
20-Week Marathon Training Plan
A 20-week marathon training plan designed for runners with a clear goal and a defined timeline. The marathon is fundamentally an aerobic event with a metabolic ceiling problem. Running out of glycogen — 'the wall' — is a fuelling and pacing failure, not a fitness failure. The training goal is to build a large enough aerobic base, develop fat oxidation efficiency, and practice race-pace running so the body knows what's coming on race day.
Why more weeks mean more base
A 20-week plan gives you something shorter plans cannot: a genuine aerobic base-building phase before the race-specific work begins. The extra weeks in the first phase aren't just adding mileage — they're building mitochondrial density, bone resilience, tendon strength, and fat oxidation capacity that the specific fitness phase and taper then convert into race-day performance.
Managing the mental length of a long build
Training for 20+ weeks is a long time to stay motivated and injury-free. Race simulations, parkruns, and tune-up races every four to six weeks provide short-term goals and honest fitness feedback. They also break the long block into sub-blocks that feel more manageable. Log your training with Coach Baz and use the weekly feedback loop to stay aligned.
Knowing when to modify the plan
A long plan has many more opportunities for illness, life events, and fatigue to interfere. The rule is to modify rather than abandon: reduce volume rather than stopping, convert a quality session to easy running rather than resting, and always protect the long run. A modified week followed by a normal week does less damage than complete rest followed by trying to catch up.
Let Coach Baz build your personalised marathon plan
This is the structure. Daash's AI coach, Coach Baz, personalises it around your schedule, current fitness, and goal — then adapts it week by week based on how training is actually going.
Get my personalised planSample training week
This is a representative week from the middle of the plan — not the first week (which starts lighter) or the peak week (which is harder). It gives you a sense of the session structure and weekly rhythm.
| Day | Session | Notes |
|---|---|---|
| Monday | Rest | The long run demands real recovery |
| Tuesday | Easy run 45–55 min | Aerobic base building |
| Wednesday | Marathon-pace run: 8 miles with middle 4–5 miles at goal marathon pace | Race-specific fitness development |
| Thursday | Easy run 40–50 min | Recovery pace, no pressure |
| Friday | Easy run 30–40 min or rest | Freshen legs for the weekend |
| Saturday | Medium-long run: 12–14 miles easy | Builds aerobic volume, not as demanding as Sunday |
| Sunday | Long run: 18–20 miles easy | The cornerstone of marathon fitness |
Why use Daash for this training plan
A static plan — PDF, spreadsheet, or fixed programme — assumes your life runs on schedule. Coach Baz adapts week by week based on what you report: missed sessions, tired legs, travel, illness, or a breakthrough workout that means you can handle more. The result is training that fits the runner you actually are, not the one who never has bad days.
- Weekly plan adapts based on how your training actually went
- Garmin integration: structured workouts sent directly to your watch
- Conversational coaching — ask Coach Baz anything, any time
- No rigid race date required — set the goal, let the plan follow
Frequently asked questions
How many days per week does this marathon plan require?
Most sessions in this plan run four to five days per week, including one quality session, a long run, and easy aerobic running. The plan is designed to be adjustable — Coach Baz can restructure around your available days each week.
Do I need a GPS watch to follow this marathon training plan?
A GPS watch or running app is helpful for tracking pace and distance, but not strictly required. Effort-based running (using a scale of 1–10 perceived exertion) works well for easy runs. For quality sessions where specific paces matter, a watch becomes more valuable.
What should I eat before a long run?
For runs under 60–75 minutes, eating beforehand is optional. For longer runs, a light carbohydrate-based meal two to three hours before the session — oats, toast with banana, or a rice-based option — provides fuel without gastrointestinal issues. Avoid high-fat, high-fibre, or unfamiliar foods on long run mornings.
How does Daash adapt the plan if I miss a session?
Coach Baz adjusts your upcoming week based on what you report. If you missed a session due to illness, fatigue, or life events, log it in Daash and the next week's plan will reflect that reality — redistributing sessions, reducing volume if needed, or modifying the upcoming quality work to account for the missed training.
Do I need to take gels or nutrition during training for a marathon?
For any long run over 90 minutes, practising race nutrition is valuable. Train with the gels, chews, or drinks available at your target race so your gut is adapted before race day. Do not try a new nutrition product for the first time on race morning.
Let Coach Baz build your personalised marathon plan
This is the structure. Daash's AI coach, Coach Baz, personalises it around your schedule, current fitness, and goal — then adapts it week by week based on how training is actually going.
Start with Coach BazRelated training plans
- Marathon Training Plan for Beginners
Your first 26.2 in 18 weeks. A beginner marathon plan that prioritises aerobic base, injury-free long run progression, and the mental resilience to cross the finish line.
- Marathon Training Plan for Intermediate Runners
Move from marathon finisher to marathon racer. This intermediate plan introduces marathon-pace long runs, mid-week quality, and a structured 3-week taper.
- Advanced Marathon Training Plan
A serious marathon block for experienced runners: 70+ mile peak weeks, back-to-back long runs, lactate threshold work, and race-specific fitness to run a fast 26.2.