Your plan reads what you run. And responds.
The coach that runs with you
It's not a PDF that ignores your life. It's a system that interprets your real week and adjusts what's next so every session makes sense.
Free during beta · Strava · Garmin
A static plan assumes you'll complete everything. That's not realism — it's fantasy.
Most running plans — the free ones, the app ones, the ones a coach sends as a PDF — are static documents. Generated once, never changed. When your life doesn't fit the plan, you have two options: ignore the plan or feel guilty. Both are bad.
How it works
The 4 moments of the engine
A cycle that repeats every week: read, design, adapt, return direction.
Reading
Understands where you are
You connect Strava. PRB imports your history. Calculates your real VDOT based on your best recent efforts. Determines your actual weekly volume — not what you think you do, but what you actually log.
Design
Builds your plan with real science
Selects the optimal training pattern for your distance + level + volume. 35 patterns available, not a single template. Structured in phases: base, specific, taper. Calibrated volume progression. Recovery weeks every 3-4 weeks.
Adaptation
Reads your real week and responds
Every week, PRB compares plan vs reality. If sessions were missed, the next week reorganizes: it doesn't repeat what was lost, it adjusts what's coming while keeping the overall plan logic. If your VDOT changed, it recalibrates all paces.
Direction
Tells you what you did, what it means, and what's next
Weekly coaching with data analysis. Per-session feedback when you ask. Visible VDOT progression throughout the plan. Updated race pace prediction.
What it's not
“It's not an AI that improvises. It doesn't generate plans with a chatbot.”
The plan logic is deterministic — based on training science, not language model predictions. Daniels' tables, Pfitzinger's periodizations, Hansons' progressions: all of it is training engineering proven over decades.
AI only intervenes at two moments: session feedback and weekly coaching. Everything else is deterministic logic.
This is what sets us apart from competitors selling 'AI-powered plans'. PRB can honestly say: the science is deterministic. AI is just the communication layer.
The foundations
Built on science proven over decades
PRB implements 4 methodologies with 35 training patterns.
Jack Daniels
VDOT tables for pace zones. The world standard in intensity prescription for all distances.
Pace zonesPete Pfitzinger
Phase-based periodization for half and full marathon. The reference for volume runners.
PeriodizationHansons
Cumulative fatigue philosophy. Shorter long runs but with higher quality frequency.
Cumulative fatigueHal Higdon
Gradual and accessible progression. Consistency and reaching the finish line for debut runners.
Safe progressionTest the engine with your next race.
Tell me your distance, your date, and what you run today.
Connect with Strava · Sync with Garmin · Free during beta