Training Zones Explained: Why Most of Your Rowing Should Feel Easy

If you've spent any time around competitive rowers, you've heard the zone acronyms thrown around — UT2, UT1, AT, TR, AN. They sound like they belong on a spreadsheet, not in a boat. But the idea behind them is simple, and understanding it will change how you train more than any piece of equipment will.

The zones, briefly

• UT2 (Utilisation 2) — Ultra-easy aerobic rowing, roughly 65% of heart rate reserve (HRR). Conversational pace. This is the bulk of serious training volume.
• UT1 (Utilisation 1) — Still aerobic, a notch harder, ~75% HRR. Sustainable for long steady pieces.
• AT (Anaerobic Threshold) — Around 82% HRR, "comfortably hard." Classic session: 8 minutes × 3 with 4 minutes rest.
• TR (Threshold/Race pace) — ~87% HRR, close to race intensity. Shorter intervals, more rest.
• AN (Anaerobic) — ~92%+ HRR, short, sharp, and unpleasant on purpose. Think 2 minutes × 5.

The part that surprises people

Elite rowing programmes spend roughly 80% of total training volume in UT2/UT1 — genuinely easy — and reserve the remaining 20% for AT/TR/AN work. This is called polarised training, and it isn't a beginner simplification; it's what national teams actually do. The instinct to make every session at least moderately hard is one of the most common ways rowers sabotage their own progress. Constantly training at "medium" intensity produces medium adaptations across the board and accumulates fatigue that blunts the sessions that are actually supposed to be hard.

The mechanism is straightforward: your aerobic base — the engine that lets you sustain power for 2000m or 6000m — is built almost entirely in the easy zones, over a long time horizon, with high volume. The threshold and anaerobic zones develop your ability to tolerate and clear lactate, which matters, but only on top of a big aerobic base, and only in the doses your body can actually recover from between sessions.

What this looks like in a real week

For an intermediate rower training five or six days a week, a polarised week might be four UT2/UT1 sessions, one AT session, and one shorter TR or AN session — never two hard sessions back to back, since threshold and anaerobic work needs full recovery to actually produce the adaptation you're training for rather than just adding fatigue.

Why this feels counterintuitive

Going easy doesn't feel like training. That's exactly why so many rowers drift out of a polarised structure without noticing — each individual session that's "a bit harder than it should be" feels like a good decision in the moment. The damage is cumulative: less full recovery between the sessions that matter, and a training week that's technically "all pretty hard" instead of genuinely easy-hard-easy-easy-hard.

If you're not sure whether your week is polarised, look at your split, HR, or RPE data honestly. If most sessions cluster in the middle instead of at the extremes, that's the pattern worth fixing first — before touching technique, equipment, or anything else.