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Guides to structuring interval workouts, choosing between AMRAP, EMOM and timed formats, training with heart-rate zones, and reading what your session data actually says.

Structure

How blocks, rounds and stations fit together

The three-level structure behind every workout, and why it is what lets one format serve a HIIT circuit, a strength complex and a race simulation.

A station is one exercise — wall balls, a row, a kettlebell swing. Stations are grouped into a block, and a round is one complete pass through every block. Four stations across two blocks over three rounds means you work through all eight stations three times, twenty-four working intervals in total.

The reason this matters is that the same three numbers describe workouts that feel nothing alike. One block of eight stations for one round is a straight circuit. Two blocks of four for five rounds is dense interval work. Eight blocks of one station, one round each, is a race simulation with a long rest between efforts.

Work and rest are set per station and separately between blocks. Short station rest with long block rest gives you clusters of hard work with real recovery between them. Even rest throughout gives a steadier aerobic session. Changing only the rest, leaving every exercise identical, changes what the workout trains.

Formats

AMRAP, EMOM and timed intervals: which to use when

Four workout styles, what each one actually measures, and how to pick the right one for the session you want.

Timed intervals fix the clock: every station lasts the same duration regardless of how much you do in it. Because the time is constant, the honest measure of progress is heart rate — the same work at a lower heart rate, or more reps in the same window.

Reps mode fixes the work instead: you go until the reps are done, so duration becomes the output. This is the format where pace is a real signal, and where slowing down across rounds tells you something about fatigue rather than about the timer.

EMOM gives each station a fixed window — every minute on the minute, or any interval you set. Whatever time you do not spend working becomes rest, so the format is self-regulating: as you tire, your rest shrinks. Watching that rest disappear across rounds is one of the clearest fatigue signals available.

AMRAP sets a time cap and counts what you complete inside it. Rounds are the output, so the score is directly comparable between sessions of the same workout. It is the format that answers "am I fitter than last month" with the least ambiguity.

Heart rate

Training with heart-rate zones during interval work

What the five zones mean, why interval training scatters across them, and what time in zone tells you that average heart rate does not.

Zones are proportions of your maximum heart rate: roughly under 60 percent for zone one, then 60 to 70, 70 to 80, 80 to 90, and 90 and above for zone five. Pair a standard Bluetooth chest strap and the run screen shows which zone you are in as you work.

Interval training does not sit in one zone the way steady cardio does. Heart rate climbs during a station, falls during rest, and climbs again — so an average across the session can land in zone three while you barely spent a minute there. Time in zone is the more useful number: it tells you how the session was actually distributed.

That distribution is what makes rest a programming decision rather than an afterthought. Long rest lets heart rate drop far enough that the next effort starts fresh, which keeps power high but pulls total time in the upper zones down. Short rest keeps heart rate elevated throughout and shifts the session toward conditioning at the cost of output per station.

Analytics

Reading your session analytics: decoupling, drift and load

What the numbers after a workout describe — and, just as importantly, what they do not claim.

Decoupling compares output against heart rate between your first round and your last. If you slow down while your heart rate climbs, output per heartbeat has fallen and the number goes negative — you were producing less for more. If output holds while heart rate rises, that is a different and more encouraging pattern.

HR drift is the simpler cousin: how far average heart rate moved from the first round to the last. On its own it means little, because heart rate rises in any hard session. It becomes informative next to pace — rising heart rate with steady pace reads very differently from rising heart rate with collapsing pace.

Training load, expressed as TRIMP, weights time by the intensity it was spent at, so a long easy session and a short brutal one become comparable numbers. It is the metric worth tracking week to week rather than session to session.

These describe what happened. They are not instructions, and no single session says much on its own — a slow round can be a missed grip or a water break as easily as fatigue. The patterns worth acting on are the ones that repeat.