Skip to content

Intensity distribution

Time in zones tells you about last week. Intensity distribution tells you about the block — the shape your training took over the last twelve weeks, and whether it was the shape you meant.

The three bands

Distribution is described against three intensity bands rather than your seven power zones, because that's the language the training research uses:

  • Easy — below your first threshold (LT1). Zones 1–2.
  • Tempo / threshold — between your two thresholds. Zones 3–4.
  • Hard — above your second threshold (LT2). Zones 5 and up.

The band boundaries come from your own zones, so they move when your zones do. There is no hidden assumption about where your thresholds sit as a fraction of FTP.

The four shapes

openkoutsi names the shape of the distribution:

  • Polarized — mostly easy riding, with the hard days genuinely hard and little in between.
  • Pyramidal — a broad easy base, less tempo and threshold, least hard riding.
  • Threshold-heavy — a large share of moderate work: the grey zone between easy and hard.
  • Almost all easy — very little above your first threshold at all.

No shape is the right one

Polarized and pyramidal are both well-supported ways to train, and which suits you depends on your event, your phase and your history. The point of this view isn't to reach a particular shape — it's to find out whether the block you did matches the block you planned. A base phase that quietly became threshold-heavy is the classic case, and it's invisible week by week.

The two ways of counting — and why they disagree

The card has a By time / By session toggle, and the two will usually give you different answers. That's expected, not a bug.

Adds up every second of every ride. This is the default, and it matches the numbers in your Time in zones chart exactly.

The catch: warm-ups, recoveries between intervals and the roll home all land in the easy band regardless of what the session was for. That inflates the easy band and makes almost everyone look pyramidal — including athletes doing genuinely polarized training.

Counts each ride whole, by what it was for. A VO2max session counts as one hard session even if most of its minutes were spent recovering between efforts.

This is how the polarization research usually counts, and it's closer to how you'd describe your own week out loud. It needs each ride to have a workout category, which openkoutsi assigns automatically from your power data.

Because the two methods answer slightly different questions, the method in use is always shown on the card. A distribution figure without its method attached doesn't mean much.

Power or heart rate

For the time-based method you can measure against your power zones or your heart-rate zones. openkoutsi uses power when you have power zones set up and falls back to heart rate otherwise, so riding without a power meter doesn't cost you the feature. The session-based method uses workout categories and so has no power/HR distinction.

Your training plan's phases

On the Plan page, the same card appears scoped to your plan's current phase — the run of build or recovery weeks you're in right now — instead of a fixed twelve weeks. That's the comparison worth making: a base phase is supposed to be mostly easy, and this is where you find out whether it was.

The window only ever runs up to today, so a phase with weeks still ahead of it won't look like it fell short.

When to take it with a pinch of salt

Two warnings can appear under the chart, and both are worth reading:

  • Partial coverage — how many rides in the window actually had usable zone data. A shape drawn from 6 of 40 rides is not describing your block.
  • Zones changed — your zones or FTP moved inside the window, so the bands weren't measured against the same boundaries throughout. Your history is deliberately frozen at the zones in effect at the time, which is right for a weekly chart but means a long window can mix vintages.

Cycling only, for now

Intensity distribution covers cycling activities. Running and swimming need their own sport-specific intensity models.