The definition is narrower than people think: a circuit is what happens when one round contains more than one movement.
A circuit is a sequence of distinct movements performed back to back as a single round, then repeated for a set number of rounds with rest between them. Four rounds of fifteen kettlebell swings plus ten burpees is a circuit. Four rounds of fifteen kettlebell swings is not, however much the rest structure looks the same.
That distinction is the one our own parser cares about, and it's sharper than the usual explanation. What makes something a circuit is the number of different movements inside one round. Not the duration, not the rest, not whether it feels like conditioning. If the round contains one movement it's interval work. If it contains several, it's a circuit.
The rest lives between rounds rather than between movements. Inside a round you move continuously from one station to the next, which is what keeps the heart rate up while local fatigue moves around your body. The kettlebell swings tax your grip and posterior chain, the burpees give those a break while taxing your chest and breathing, and by the time you're back at the kettlebell your hands have had ninety seconds off even though you haven't stopped.
That rotation is the reason circuits can carry meaningful volume without any single tissue giving out. It's also why they're a poor tool for progressive loading: when you reach the third station you're pre-fatigued by the first two, so the weight on the bar means something different every time.
Movement ordering does most of the work in a well-built circuit. Put the two most similar movements as far apart as you can, and put anything requiring grip or a stable spine early rather than last. A circuit ending with a heavy carry after two hinge patterns is a circuit ending with a grip failure.
Round times are the honest read, and they should be recorded. A four-round circuit at 3:10, 3:25, 3:40, 4:05 tells you the prescription was slightly too dense. The same circuit at 3:20, 3:22, 3:25, 3:24 tells you it was right. The total time hides both.
Our Hyrox conditioning block is four rounds of a 20-metre sled push, twenty kettlebell swings at 24 to 32 kilos, a 20-metre heavy farmer's carry and ten burpees, with ninety seconds of standing rest between rounds. Round one takes most people about three minutes ten. What's interesting is where the extra time appears in round four. It isn't the sled, which is mostly leg drive and stays honest. It's the carry, because the swings have already taken your grip, and it's the transitions, because you're now walking between stations instead of moving between them. Total time for the block is around twenty minutes including rest. The number worth writing down is not that twenty. It's the four round times and the gap between the first and the last, because a spread wider than about twenty percent means the density was too high and the rest should go up before the load does.
4 rounds: 20m sled push + 20 kettlebell swings + 20m farmer carry + 10 burpees, 90 sec rest
Circuit work in the app is paced by you rather than by the clock, because a round takes as long as it takes. You tap once when the round is done, the timer records that round's split, and the prescribed rest starts and counts itself down before rolling straight into the next round. So the only thing you have to remember mid-effort is the one tap.
The round card shows the movements for the round you're actually in, with load guidance kept visually secondary to the quantity, and duplicate load phrasing collapsed so you don't read the same weight three ways. Splits are stored per round, which is what makes the round-to-round spread visible afterwards instead of being lost inside a total.
If you log a poor readiness check-in before the session, the rounds get cut before you start rather than mid-effort. The reduction is proportional and recorded as a change with its reason attached, ranging from a ten percent cut on a mildly off day up to half the rounds when readiness and soreness are both bad, in which case the protocol is also marked recovery-only.
Performing several different movements back to back as one round, then repeating that round with rest in between. The defining feature is the number of distinct movements inside a round. If a round contains one movement repeated, that is interval work rather than a circuit, even when the rest structure looks identical.
Put similar movements as far apart as possible so no single area is loaded twice in a row, and put anything that depends on grip or a braced spine early rather than last. A circuit that finishes with a heavy carry after two hinge patterns is really testing your grip. Order changes the difficulty more than load does.
Enough that round four looks like round one. In practice that is 60 to 120 seconds for most conditioning circuits. The check is the spread in your round times: if the last round is more than about 20 percent slower than the first, add rest before you reduce the work, because the density rather than the load is what broke.
Not effectively. A circuit is built to stop the target tissue recovering between exposures, so your limiter becomes breathing or grip rather than the muscle you intended to load. Strength needs full recovery and high load, which is the opposite arrangement. Circuits are excellent conditioning and a poor substitute for working sets.
Build a plan and Fire Your Coach will schedule the structure, run the clock, and record what actually happened round by round, so next time the prescription starts from your real numbers.