The core principle: compute, then explain
Most “AI coaching” is a chatbot guessing from a single prompt. Peakfy is built the other way around. First a deterministic engine calculates the objective figures from your training and recovery data. Then a large language model — the coach — interprets those figures in plain language and adapts your plan. The numbers come from maths you can trust; the explanation comes from a coach that remembers your history.
A hard rule runs through the whole product: a value or colour is only ever shown when it has actually been calculated. Peakfy never fabricates a score to fill a gap. If the data isn't there yet, it says so.
Training load: what you've actually done
Peakfy quantifies each ride's stress and tracks how load accumulates over time — the same concepts serious coaches have used for years:
- a per-session training-stress figure derived from intensity and duration;
- a rolling chronic load (your longer-term fitness) and acute load (your recent fatigue);
- the balance between the two, which describes whether you're building, holding, or overreaching.
These are established endurance-training constructs (training-stress scoring and acute-versus-chronic load). Peakfy computes them from your files rather than asking you to guess — and the coach turns the ratio into a decision: push, hold, or ease off.
Fitness
Chronic load
Your longer-term training base — what you can sustain — built patiently over weeks.
Fatigue
Acute load
The cost of your recent training. Too much for too long and quality falls; the plan responds.
Readiness: how recovered you are
Some days you're firing; some days you're flat. Peakfy reads the signals your body and devices already produce — heart-rate variability (HRV), resting heart rate, sleep, and your own rating of perceived effort — and turns them into an honest daily readiness picture on a simple green / yellow / red scale.
Crucially, it's honest. When the signals say to back off, Peakfy tells you to back off — even if you'd rather train. Recovery comes before performance, because that's where the adaptation actually happens.
Power, zones and your FTP estimate
Peakfy works in a seven-zone power model (the widely used Coggan-style zones), anchored to an estimate of your functional threshold power (FTP) that updates as your data does. Every structured session is prescribed in those zones, with exact power and heart-rate targets — so “Zone 2” becomes a real number you can hold, indoors or out.
Structured sessions and periodisation
Fitness is built with structure, not random hard days. Peakfy builds each session fully — the interval profile, the targets, the fuelling in grams of carbohydrate and millilitres of fluid per hour — and sequences your weeks so that hard days are hard, easy days are genuinely easy, and rest lands when it should. The plan bends around real life: miss a day, travel, or wake up wrecked, and it re-plans around you rather than the other way around.
Grounded in sport science, built with pros
The methods above aren't invented for a marketing page — they're the established language of endurance training. Peakfy is co-developed with ex-professionals and sport scientists from the pro peloton, built on the exact training the world's best riders use, and tested by riders who race, and win stages at, the Giro d'Italia, the Tour de France and the Vuelta. Every plan is grounded in current sport science, then adapted to your level.
The frameworks referenced here — training-stress scoring, acute-versus-chronic load, HRV-informed readiness, threshold-anchored power zones and structured periodisation — are widely used across endurance sport science and coaching. Peakfy's contribution is computing them correctly from your own data and explaining them like a coach.
What Peakfy is not
Peakfy is a sport-science training tool, not a medical device. It doesn't diagnose, treat, or give medical advice. It helps you train smarter from your performance and recovery data. If you have a health concern, that's a conversation for a qualified professional — not an app.