PX7 Training · Articles

PX7 Training Method · 5 min read · 2026-04-17

The seven zones, explained

How the PX7 Training Method carves the intensity continuum into seven named zones — and why two of them are labelled as avoid-zones on purpose.

Every session PX7 Training assigns lives in exactly one of seven zones. They are not borrowed from heart-rate conventions; they are a running-specific system derived from your threshold — expressed as threshold pace for pace-first runners, critical power for power-first runners. Five of them you train in. Two of them you're told to stay out of. This is the structure the PX7 Training Method is built on.

How the zones are computed

Every zone is the same percentage band of your threshold, regardless of which units you train in. Threshold itself is derived from your most recent assessment — a time trial, a recent race, a power test with a footpod, or a manually entered value you know from elsewhere. When you do a new assessment, every zone shifts automatically — and so does every remaining session in your current plan. Nothing about your plan is frozen.

Intensities are expressed as a percentage of threshold: 60 percent is very easy, 100 percent is threshold exactly, 115 percent is hard VO₂max territory. Those percentages work identically in both modes. The app shows you the concrete target in the unit you prefer — a pace window in minutes per kilometre, or a power window in watts — but the underlying zone definitions are the same either way.

The five training zones

Z1 — Easy (60–76%)

Recovery jogs, warm-ups, cool-downs. Should feel conversational and almost too slow.

Z2 — Aerobic (77–87%)

The workhorse zone. Most of your weekly volume lives here. Steady and sustainable, still conversational. Everything good about aerobic adaptation happens at this intensity.

Z3 — Threshold (94–100%)

Controlled hard. Long tempos and sub-threshold intervals. The single highest-leverage zone for endurance improvement.

Z4 — VO₂max (103–115%)

Three-to-eight-minute repeats at a pace you could only hold for a mile or two. Expensive to recover from; used sparingly.

Z5 — Anaerobic (>115%)

Short, sharp repeats — 30 seconds to two minutes. Neuromuscular and peaking work, not metabolic conditioning.

The two avoid-zones

Between Z2 and Z3, and between Z3 and Z4, sit two narrow bands most training apps ignore. We name them and label them as avoid on purpose.

NOX — Transition (88–93%)

Too hard to recover from, too easy to drive threshold adaptation. This is where well-meaning runners spend their "medium-effort" day and leave it tired without a clear training stimulus.

NOY — Over-threshold (101–102%)

Just above threshold. A threshold session (Z3) that drifts into NOY becomes too hard to hold; a VO₂max session (Z4) that slides back into NOY becomes too soft to adapt. Step across this band cleanly, don't hover in it.

The two avoid-zones exist on the zone list not because you'll use them, but because seeing them labelled is the clearest way to avoid drifting into them. When you find yourself running in NOX or NOY on an unstructured day, the honest move is usually to slow down into Z2.

What this looks like in the app

Open PX7 Training and your zones page shows the full list with your personal ranges beside each — in pace if you've picked pace mode, in watts if you've picked power mode. Your next session's zone is printed on the session card, along with the exact window you're aiming for. Log enough sessions and your 80/20 balance surfaces as a single metric — the percentage of your completed training that landed in Z1 and Z2. Eighty is the target.

Seven zones sound like a lot. In practice, the training you do only ever touches three or four of them in a given week — and the method is disciplined about which.

Written by Jørgen Larsen for PX7 Training.