Early access · Now on iOS
Your training,
bound together.
The smart workout notebook for lifting, yoga, Pilates, barre, cardio, food, and the weeks where you mix them. Write naturally. Keep every raw word. Let cited rules—not AI guesses—run the numbers.
25+ peer-reviewed sourcesEvery number traceableRaw notes stay yours
The notebook loop
Paper feel.
Engineering in the spine.
One quiet page connects what you did, what you ate, how you recovered, and what should happen next. There is no dashboard to maintain and no chatbot waiting for a prompt.
- 01WriteTraining, food, bodyweight, context.
- 02ConfirmEdit the structure before it becomes history.
- 03Read the marginGet the next action with its rule attached.
However you move
A plan shaped around your actual practice.
Pick the movement styles you enjoy, the days you have, the equipment in reach, and the time the session really gets. Flexbound treats every answer as a constraint—not a preference it can quietly ignore.
See how the planner makes decisions →
4 days · 45 minutes · home dumbbells · yoga on Sunday
The hard line
AI in the margins.
Never in the math.
Language models are good at explanation. They are not the authority on your calories, training load, or next set. Flexbound publishes that boundary.
The calculators decide
- 01 Calories, macros, and adaptive TDEE
- 02 Estimated 1RM, volume, and progression
- 03 Deload thresholds and pain responses
- 04 Workout structure and goal pacing
Versioned rules · cited sources · audit trail
The AI may only
- 01 Explain a finished recommendation
- 02 Write a weekly review from locked facts
- 03 Draft an ambiguous parse for you to confirm
- 04 Summarize approved research
If the prose invents a number, it is discarded
Built for the long record
A logbook you can still trust in ten years.
The visual language is quiet because the record matters more than the software. No confetti, public feed, streak anxiety, or synthetic coach persona.
- User truth
- What you wrote, edited, and corrected. Never mutated.
- Nutrition truth
- Source-backed estimates with assumptions and confidence visible.
- Methodology truth
- Versioned rules stored as data—not hidden in a prompt.
Useful before launch
Bring the method to your next session.
Read the evidence, print a clean log, or run the same transparent calculators the app will use. Everything here is free today.
Pricing
Free captures.
Pro compounds.
The notebook stays useful before you ever pay.
- Unlimited raw journaling
- Deterministic workout parsing
- Food notes and bodyweight
- Backup, restore, and sync
- Sourced calorie and macro estimates
- Weekly reviews and workout plans
- Deload and pain-flag signals
- Unlimited history and saved meals
Fair questions
Straight answers.
What is Flexbound?
Flexbound is a workout notebook app for iOS. You write training and food notes in your own words; the app parses them into structured sets, meals, and bodyweight data without ever rewriting your raw entry. Deterministic math handles progression, macros, and TDEE. AI only writes and explains.
Does AI calculate my calories or training numbers?
No. Calories, macros, TDEE, estimated 1RM, volume, and progression all come from versioned deterministic calculators grounded in peer-reviewed research. AI is architecturally forbidden from producing numbers; it can only rephrase and explain results the math already produced.
Is Flexbound free?
The core notebook is free forever: unlimited raw journaling, deterministic workout parsing, food notes, backup and sync. Flexbound Pro adds sourced calorie and macro estimates, weekly reviews, workout plans, and unlimited history.
Can I use Flexbound if I train at home?
Yes. You declare where you train and exactly what you own. Plans are built only from movements your equipment can perform, and if a movement pattern is not honestly trainable with your setup, the plan says so.
Do I have to be a lifter to use Flexbound?
No. Choose lifting, yoga, Pilates, barre, HIIT, steady cardio, or any recoverable combination. Each practice gets scheduling logic and limits that fit what it actually does.
When does Flexbound launch?
Flexbound early access is open on iOS. Email us to join the first cohort.
Early access on iOS
Open the notebook with the first cohort.
Flexbound early access is open on iOS. Email us to join and bring the notebook to your next training week.