The science behind your plan

Every session has a reason. Here's the thinking behind your plan, in plain terms.

Your plan is built in phases.

It moves through a base phase, a build phase, and a peak, then eases into race day. Every fourth week is a recovery week — lighter on purpose — so your body absorbs the work instead of digging a hole it can't climb out of.

Readiness decides how hard you go today.

Each morning you get a 0–100 readiness score, built from your heart-rate variability (HRV), resting heart rate, sleep, and how you say you feel. Two rules never bend:

First, feeling good can't override a tired body. If your HRV is suppressed or your resting heart rate is up, a cheerful check-in can't lift you out of a "back off" day — the numbers win.

Second, two red mornings in a row means a rest day. No streak is worth training through a body that's asking to stop.

The taper is engineered, not guessed.

In the last stretch before your race, training volume comes down so you arrive fresh. But freshness has a sweet spot — rest too little and you're flat, rest too much and you lose fitness. The plan aims for the window that has you peaking on the start line, not the Tuesday before.

Your zones come from your own tests.

Your training zones are set by your own numbers — FTP on the bike, critical swim speed (CSS) in the pool, a 5k for the run — and re-tested on a schedule, so the plan tracks your real fitness instead of a guess. Your fuelling targets use your fat-max and sweat rate, so they're yours, not a generic table.

Different methods for different athletes.

You choose how your plan is shaped: polarized (mostly easy, a little genuinely hard — the safest, best-evidenced default), Norwegian sub-threshold (the lactate-guided method behind Blummenfelt and Iden), or pyramidal (a big aerobic base with steady threshold work). The plan applies the one you pick.

None of this is hidden. If a session ever doesn't make sense, open it — the app tells you exactly why it's there.