A week by week workout plan beats a fixed 12-week programme for most busy adults, because it adapts to the week you actually had instead of the week a spreadsheet predicted.
Please check with your doctor before starting a new plan, especially after a long break, an injury or if you take medication.
What is wrong with a fixed 12-week programme?
Nothing, on paper. A 12-week programme is written once, in advance, for an imaginary person who sleeps eight hours, never catches a cold and has no deadlines. Nobody is that person.
Then week 3 arrives with a work trip, or week 5 with a child who has brought home a stomach bug. The programme doesn't notice. It simply says "Week 6, Day 2" and waits for you to cope.
Falling behind feels like failing. People quit, or jump ahead and train at a level they haven't earned yet. Neither helps.
Why does a week by week workout plan work better?
A week is short enough to react to and long enough to show a pattern. Planning one week at a time lets you:
- Ease off after a hard week. You get a lighter next week instead of pushing through a plan written months ago.
- Step up after an easy week. If last week felt comfortable and you finished everything, you get a nudge.
- Keep a missed week small. Nothing piles up. You don't owe the programme three sessions.
- Plan recovery instead of hoping for it. Many coaches build lighter weeks into training for exactly this reason.
It is the same idea as progressive overload: small, steady changes based on honest feedback.
How does the weekly plan builder adjust each week?
The weekly plan builder asks a short set of questions and builds a 7-day plan from the app's library of more than 3,000 real workouts. First time? You answer five setup questions. Coming back? You also answer five check-in questions about how hard last week was, how tired you feel, how many sessions you finished and any pain.
Those answers set next week's intensity. "Strain" is the average of how hard the week was and how tired you feel.
| Last week | What the next week does |
|---|---|
| Pain, or tiredness of 9 or 10 | Recovery week: -30%, one fewer workout day |
| It was week 4, 8 or 12 | Planned easy week: -20%, one fewer workout day |
| Strain of 3 or less, every session finished | +20% |
| Strain up to 5, every session finished | +10% |
| Strain up to 7.5 | Holds steady |
| Strain above 7.5 | -10% |
Only a full week earns a step up. Finish "most" sessions and the best you get is a hold.
What does that look like with real numbers?
Here is an example. An intermediate trainee doing 3 workouts, medium sessions and a general fitness goal starts at 80%. Last week they rated it 4/10 hard and 4/10 tired, and they finished every session. Strain is 4, so the next week is +10%, giving 90%.
Had the same person reported pain, the builder would switch to a recovery week instead: 30% lighter, one fewer workout day and no For Time or Tabata workouts. The plan page shows a "How we worked out X%" list, so every step behind the number is visible.
Where does your progress get tracked?
Not in the app. The builder doesn't save your plan or track anything, and your answers aren't stored or sent anywhere. Refresh the page and the plan is gone, so copy or download it first.
Tracking happens in your own notes, a Word document or an AI tool such as Claude or ChatGPT. That AI tool is independent and does not represent Fatboy Fitness in any way. See using AI with the weekly plan builder, or start gently with the 30-day restart plan.
FAQs
Do I have to follow the plan for 12 weeks?
No. The builder makes one week at a time, and you decide whether to come back for the next one. If you do, you can pick a starting week from 2 to 12.
Is the weekly plan builder free?
Yes. It is free, with no account and no sign-up.
The bottom line
Real weeks are messy, so training should bend. Plan one week, be honest about how it went, then let the next respond. Build your weekly plan.
Go train, FATBOY.
This article is general information, not medical advice. Train at your own risk. If you have a health condition, take medication or are unsure whether exercise or a diet change is right for you, talk to your doctor first.
- weekly plan
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- week by week