What is an Ergometer?

Ergometer, erg, indoor rower: same machine, three labels

Three words point at the same piece of equipment, and the word a person picks signals where they came up in the sport. Coaches writing season plans and exercise physiology textbooks say "ergometer" because it is the technically correct term (Greek ergon, meaning work, plus metron, meaning measure). Inside any boathouse no one bothers with the full word. A varsity captain shouting from the front rack says "erg" every time: "set up the ergs for 5K trials." Commercial gyms call the same thing a "rowing machine" or, lately, just a "rower." All three labels mean the same hardware: a sliding seat on a steel monorail, a foot stretcher with adjustable heel cups, a chain handle, an enclosed flywheel, and a monitor reading work in pace units.

How an ergometer converts a pull into a number

Each stroke pulls the chain, which spins a flywheel inside the cage. The flywheel meets resistance from air entering through vents in the housing. Between strokes the wheel slows. A magnetic sensor on the housing reads precisely how quickly the wheel decelerates, the PM5 firmware solves for the work the rower put into the chain on the previous stroke, and the answer appears on screen as a /500m split. Watts, calories per hour and cumulative meters are secondary readouts from the same underlying calculation. The machine itself never moves. There are no motion sensors, no GPS, no boat speed. Everything on the display is computed work expressed in rowing-equivalent pace units.

The damper lever on the side of the flywheel cage adjusts how much air enters per stroke. Set to 10 the wheel grabs more air and decelerates harder, so the catch feels heavy and the back end of the stroke loads up fast. Set to 1 the wheel spins freely and the stroke feels like a quick, light single. The damper position alone does not change the score on the PM5. What does change the score is drag factor, the number found under More Options on the PM5, which combines damper position with the air density of the room. US heavyweight men typically race C.R.A.S.H.-B at drag factors of 125 to 135. Lightweight women usually train at 110 to 120. Drop any /500m split into the erg pace calculator for the matching watt, calorie and predicted distance values.

Why the Concept2 is the standard machine of US rowing

Concept2 is a family-owned company in Morrisville, Vermont that has been shipping a fundamentally consistent ergometer design since 1981. The current model is the RowErg, badged simply as the Concept2 RowErg since around 2021. Before the rename, the same machine carried the Model D (standard 14-inch seat height) and Model E (taller 20-inch seat height, easier on the knees during get-on and get-off) names. The internals across all three are essentially identical. The reason this product dominates US college rowing is calibration. A 2k score pulled on a Concept2 in the Brown boathouse in November reads against a score pulled on a Concept2 at Stanford in March within stroke-for-stroke precision. That single property is what makes the machine the recruiting currency of the sport. IRA programs publish 2k roster cutoffs against it. Eastern Sprints qualifiers are gated on it. C.R.A.S.H.-B Sprints in Boston has required Concept2 calibration on every machine on the floor since the first event in 1982.

How does the ergometer differ from rowing on the water? The geometry is similar but the physics is not. The chain pulls in a straight line, while an oar arcs through an angled gate. The flywheel resistance is constant and predictable, while water resistance shifts with hull speed, wind, set, swell and crew rhythm. There is no balance to maintain, no shell to keep flat, no coxswain to listen to, no lane to hold. A strong erg score is the floor for a good rower, not the ceiling. The athletes who turn watts on the flywheel into boat speed are the ones who can take that engine and apply it cleanly to a stroke that has to thread eight other rowers, a hull, and a moving environment together. Erg pieces also remove the synchronization demand of an eight: the PM5 monitor measures one athlete in isolation, while race-day boat speed depends on eight athletes catching, driving and recovering in tight synchronization with each other.

Reading the PM5 monitor

• /500m split: the projected finishing time the PM5 calculates for the next 500 meters at the current rate of work. A reading of 1:42 means the rower is on pace for a 1 minute 42 second half kilometer. Every US race plan, training zone and athlete comparison anchors on the split because it is unambiguous and converts directly to boat speed.
• Watts: instantaneous power output into the flywheel. Concept2 publishes the relationship as watts equal to 2.80 divided by the cube of pace seconds per 500 meters. A 1:45 split is roughly 268 watts. A 1:30 split is roughly 425 watts. The cube makes the climb brutal: halve the pace number and watt output multiplies by eight.
• Calories per hour: the PM5 estimate calculated as four times watts plus 300 for resting metabolism. Repeatable across sessions and useful as a relative training-load proxy, but not a nutritionist-grade number.
• Stroke rate (spm): strokes per minute. Steady-state aerobic work sits at 18 to 20. Threshold pieces run 26 to 28. Race rates in a varsity 1V eight open the start at 38 to 42 and settle through the body of the race at 32 to 36.
• Distance: meters of computed work, not meters traveled. The machine is bolted to the floor. The display converts flywheel work into rowing-equivalent meters using the Concept2 calibration constant.

How US programs actually use the erg

The ergometer carries three loads inside a US program. Load one is the winter. From mid-November through February most boathouses on the East Coast, in the Midwest and across parts of the Pacific Northwest cannot put hulls on the water safely, so the entire fitness build for the spring sprint season happens indoors on the ergs. Load two is fitness testing. The 2k erg score is the single most scrutinized data point in US collegiate rowing recruiting. Coaches at IRA, EARC, Pac-12, Big Ten and ACC programs publish target 2k times by class year and weight category, and high school athletes who cannot hit those numbers do not get roster offers. The 5k, the 6k and the 30-minute test fill out the aerobic battery. Load three is lineup selection: erg scores sit alongside on-water seat-racing and timed pieces as the primary inputs when a coach builds the varsity 1V, the 2V and the freshman boats.

Recording one number is easy. Tracking a 35-athlete roster across a fall head-racing block, a winter erg build, a spring sprint season and a summer USRowing trials campaign is a database problem dressed up as a spreadsheet. Row HQ coach tools attach every test to the right athlete the moment the PM5 stops, plot fitness trajectory across the season, and surface a quietly fading novice or a freshman about to overtake the JV stroke before the next seat-racing night begins.

The standard US erg test pieces

These are the ergometer protocols on the trial sheet at most US college and prep school boathouses:

• 2,000 meters (the 2k): the Olympic race distance and the recruiting benchmark. Most varsity-grade openweight men finish between 6:00 and 6:50. Varsity women between 6:45 and 7:30. The 2k is the entry requirement for every C.R.A.S.H.-B Sprints category and every NCAA roster slot.
• 5,000 meters (the 5k): aerobic endurance test, rowed at threshold or just below. Most varsity squads finish in 17 to 22 minutes. Flags athletes who run out of aerobic engine partway through and need a winter base block.
• 30-minute piece: total meters covered in half an hour at sustained threshold pace. Pacing discipline test as much as fitness test.
• 60-minute piece: long aerobic build at UT1 or UT2 intensity, used by some programs as the February baseline before the season-opening 2k retest.
• 4 x 2,000 meters or 8 x 500 meters intervals: race-pace specificity work. The 8 x 500 with two minutes rest is a particular favorite at US scholastic programs because it teaches freshman novices how to suffer at race rate without yet asking for a full 2k.

Every result on the trial sheet needs the athlete's bodyweight that morning logged next to the time, plus the drag factor used. Bodyweight matters because lighter rowers face a real power-to-weight disadvantage on the erg that the World Rowing weight-adjusted formula corrects for. Drag factor matters because a 6:30 at 130 drag and a 6:30 at 100 drag are different efforts. Without both numbers the sheet is only half a result.

C.R.A.S.H.-B Sprints and the indoor circuit

Indoor erg racing grew into its own sport behind one event. The Charles River Association of Sculling Has-Beens, better known as C.R.A.S.H.-B Sprints, has run every February in Boston since 1982. It draws over two thousand entries across open, collegiate, masters and lightweight categories on a single weekend, and a strong showing on the C.R.A.S.H.-B leaderboard is a recruiting signal college coaches read directly. The World Rowing Indoor Championships moved onto Concept2 calibration as soon as the international federation took the event on. The Concept2 online ranking system runs year-round and lets a Princeton junior compare a 2k against a Yale senior or a New Zealand U23 in the same minute the screen flashes the time.