Erg Splits Explained: What /500m Means and How to Hold One

2:04. Then 1:58, then 2:07, and you have no idea whether the piece is going well. That number is your split, the time it would take to cover 500 metres at the speed of the stroke you took, and learning to read it is what stops the erg behaving like a random-number generator. This guide owns the split as a unit: what /500m means, how it maps to watts and finish time, why it drifts, what different splits look like, and how to hold one.

What /500m means

A split is a pace, the time 500 metres takes at your current speed, like a runner's pace per kilometre. Smaller is faster. A 2:00 split means 500 metres every two minutes, so a 2000 m piece at 2:00 takes 8:00 and a 5000 m piece takes 20:00, and the arithmetic is one line: time = split x distance / 500. Run it backwards and a goal time becomes a target split. A 7:00 2k is 420 seconds over four 500 m chunks, so 1:45.

Why 500? Races are timed in 500 m sectors, the standard race is four of them, and the unit carried over to the machine: the monitor reports pace per 500 metres on the RowErg and SkiErg, and per 1000 metres on the BikeErg, so a BikeErg split reads about double for the same effort.

A split is a rate. You can hold 1:45 for 20 strokes and never see it again, so the result is the average split across the piece, the second number the monitor gives you.

Split, watts and pace: one effort, three units

The monitor measures the flywheel. Watts come from pace through a fixed formula, watts = 2.80 divided by pace cubed, with pace in seconds per metre, so a 2:05 split is 125 seconds over 500 metres, 0.25 seconds per metre, and 2.80 / 0.25 cubed = 179 W. Three anchors worth memorising: 2:00 is 203 W, 1:45 is 302 W, 1:30 is 480 W.

The cube is the part people miss, because each second of split gets more expensive the faster you go. One second off 2:00 costs about 5 W. Off 1:40, 11 W. Off 1:25, 21 W. Watts, not split, are the honest scale for comparing two efforts, since a 5-second gain at 2:15 is 17 W and the same 5 seconds at 1:35 is 72 W; the erg calculator converts in both directions and turns any split into 2k, 5k and 30-minute results.

Two things do not change the split. Damper and drag factor change how the stroke feels; Concept2 files the damper lever alongside the gears on a bike, meaning it changes how the pull loads up rather than how much power the flywheel demands, and the monitor reads drag factor so it can report the power you produced whatever the lever says. Two rowers at drag 105 and 135 pulling 250 W both see 1:51.9. Body weight is the other. A 60 kg rower and a 95 kg rower holding 2:00 both produced 203 W, and what it costs each of them comes later.

Why the number drifts inside a piece

Three things move the split.

The stroke you took. The monitor computes pace for every stroke, and a single stroke is noisy: a soft catch, a rushed slide, a breath at the wrong moment, and the per-stroke split swings 3-5 seconds while your effort has barely changed. That is why both numbers sit on the screen. Read the per-stroke split as feedback on your last stroke, the average as the truth about the piece. Chase every flicker and a steady row turns into a series of surges.

Fatigue. Power per stroke falls as you tire. The body hides it by taking more strokes, so the tell is a split that holds while the rate creeps from 26 to 30, the fade beginning a few hundred metres before the split gives way. Rate you choose is strategy; Josh Dunkley-Smith's 5:35.8 world record was rowed at 34 strokes per minute. Rate that climbs on its own is compensation. Concept2 puts slide-control work below 22 strokes per minute and sprinting at 36 and up, and most 2k racing sits between, around 28-34.

Distance. A split only means something next to a distance: 1:45 for 500 m is a warm-up. Hold it for 10k and you are in rare company. A long-running Concept2 forum rule of thumb, Paul's Law, says a balanced athlete's split slows about 5 seconds for every doubling of distance, so 1:45 for 2k points to about 1:52 for 5k; a much bigger gap says endurance is the weak leg, a smaller one, speed.

Then there is the drift you bring with you. When rowers repeated a maximal 2k three times, the first trial showed a hard start and a steady power fade, while trials two and three moved to a more conservative start with an end spurt, with a typical error of 2.4% in performance across the three. The second attempt is where the split becomes yours.

Reading the Concept2 monitor

The PM5 shows the same piece several ways, and which one you look at changes how you row.

• Units. Press Units at any time, during the piece or in the results, and the display cycles through pace, watts and calories. Pace and watts both show the per-stroke value and the average. Calories shows a total and a per-hour rate.
• Display. Press Display to cycle through All Data, Force Curve, PaceBoat, Bar Chart and Large Print. All Data is the working screen, Force Curve is a technique tool (what the curve should look like belongs to the sibling guide on indoor rowing technique), and Bar Chart draws one bar per stroke, so bars that shrink while the rate climbs are the fade, drawn for you.
• Projected finish. On the All Data screen, a distance workout shows the time you will finish in at your current pace, and a time workout shows the metres you will reach. The most honest number on the screen.
• PaceBoat. A boat moving at a set pace next to yours. When the number stops meaning anything at 1400 m, "stay level with the boat" still does.

Two habits. Set a workout, distance or time, rather than rowing on the open screen, so the average and the projection exist, and decide before you sit down which number you steer by: watts for a fixed-rate piece, average split for a race, the force curve for a technique row.

Split ranges by body size and experience

There is no single good split. There is a good split for a distance, a sex, a weight class and a training age, and the table anchors 2k results to the split and the watts behind them, from the world records down to a first test. Read it left to right. Find the finish time you have or want; the split column is what the average on your monitor should read, and the watts column is what that effort costs in power, the number that stays comparable on the SkiErg. The last column is club-coach consensus, not a standard. Look yourself up: the Concept2 rankings filter by sex, age, weight class and machine.

Body size moves these rows a long way. Concept2 draws the lightweight line at 75 kg (165 lb) for men and 61.5 kg (135 lb) for women, and the gap between the open and lightweight records above, 21 seconds for men and 33 for women, is the size effect at the top; lower down, in 38 male collegiate rowers, 2k time correlated with body mass (r = -0.81), lean mass (r = -0.82) and height (r = -0.80). The nuance is which kind of mass. In 200 Hungarian club rowers, more skeletal muscle meant a faster 2k in men while body mass on its own went the other way, and in women higher body mass and body fat went with a slower time. Muscle pulls the flywheel. Everything else is along for the ride.

That is why Concept2 publishes a weight-adjusted score, body weight in pounds divided by 270, raised to the power 0.222, multiplied by your time, because a heavier rower drags more boat on the water, a penalty the erg never charges. Two athletes both row 7:00. At 70 kg that adjusts to 6:11, at 90 kg to 6:32, and the weight-adjusted erg calculator runs it. Use it to compare rowers, never to excuse a split to yourself.

How to hold a split

Holding a split is a skill. Mostly the skill of not chasing the number.

Pick it before you sit down. From a recent test, from the 2k predictor if you are moving between distances, or from Paul's Law above. Not at 300 m. A split chosen there, when you feel great, is the wrong split.

Even is cheaper than the average suggests. The cube law punishes swings. Row the first 1000 m at 1:50 and the second at 2:10 and the monitor reports an average of 2:00, the same as rowing 2:00 the whole way, but you spent 2% more energy for the same 8:00, and the penalty grows faster than the swing. Across 106 World and European championship A-finals, medallists paced with less variation than the rest of the field, a coefficient of variation of 1.72% against 2.00%.

A small lift at the start is normal. A big one is a loan. The same study saw the first 500 m fastest for 78% of crews, and an analysis of Olympic, World Championship and British Indoor Championship results put the elite indoor profile at 101.5%, 99.8%, 99.0% and 99.7% of average speed across the four 500s, the same shape for winners and losers, men and women. For a 2:00 average that is 1:58, then 2:00, 2:01, 2:00. Two seconds, not ten. When 13 national-level rowers tested a fast start, 107% of target power for the first 500, against an even 1500 m, the times matched to within a second, but the fast start pushed blood lactate up sooner and kept it there longer, and the rowers liked it least. You buy nothing with the surge. You pay for it from 1200 m.

Hold it with power first, rate second. For the first three quarters of a piece, keep the rate where you set it and make the split with the drive, and if the average slips, fix one thing, a longer, quicker leg drive for ten strokes, then check. Move the target in 1-second steps. Never 5. Save the rate rise for the last 500 m, where the 2K erg pacing guide takes over.

Read the average, glance at the stroke. Look at the screen every 10 strokes and ask two things: is the average within a second of target, and is the rate where I put it? Yes and yes means do nothing. The hardest instruction in rowing.

Practise it at distances that do not hurt. Twenty steady minutes holding an average inside 1 second of target teach the feel of a number better than any test. Which split those pieces sit at is a zone question, and the sibling guide on erg training zones owns it; how to organise weeks of them toward a race is the 2k erg training plan guide.

How Movement Rebels fits

A split on its own is a number on a monitor. Connected, it becomes a trend the coach can read. Connect your Concept2 Logbook and every piece lands in your training log with its split, watts, stroke rate and, if a strap was paired, the heart rate it cost, next to your Garmin or Apple Health data and the lifts you logged in the calendar. If your recent erg sessions are covering less ground for the same average heart rate, HRV has slid for four mornings, and Tuesday's calendar shows the heavy pull session you logged, the coach reads the pattern as a load signal rather than an erg problem, and the next weekly plan puts the hard piece where sleep and HRV say it will land. What the coach does with a rowing session is its own guide.

Set the workout as a distance, not an open row, so the average split exists for both of you to read.