Training zones explained
The 5-zone system
Norvin uses the British Rowing 5-zone framework to define training intensity. Each zone produces a specific physiological adaptation, so rowing each session at the intended intensity is how the plan builds what it's meant to.
The five zones are:
- UT2 · Easy — Builds your aerobic base. You can chat in full sentences (RPE 2–4).
- UT1 · Steady — Develops aerobic endurance. You can talk in phrases (RPE 4–6).
- AT · Threshold — Raises the pace you can hold. Short sentences only (RPE 6–7).
- TR · Speed — Builds race speed and oxygen uptake. A few words at a time (RPE 7–9).
- AN · Sprint — Builds peak power. No talking (RPE 9–10).
Most of your training sits in UT2 and UT1: they build the aerobic base everything else depends on. The harder zones raise the pace you can hold and your top-end speed, and they work best in small doses.
How Norvin calculates your zones
Your zones are calculated from your 2k Pace — the average Pace from an all-out 2000m test. The 2k is the gold standard benchmark in rowing: it taxes both aerobic and anaerobic systems and gives a reliable picture of current fitness.
From that single number, Norvin derives percentage-based thresholds for each zone. As your fitness improves and your 2k pace gets faster, all your training zones shift accordingly.
Why the distribution matters
Research consistently supports a Polarized approach: roughly 80% of training volume in UT2 and UT1, with the remaining 20% in AT and above. This balance maximizes aerobic adaptation while leaving enough recovery capacity to absorb the high-intensity work.
Training too much in the middle — not easy enough to recover, not hard enough to drive adaptation — is one of the most common mistakes endurance athletes make.