Stroke Rate, DPS and Ratio Tool
Rate is what the PM5 monitor reports in real time. Distance per stroke is what tells you whether each one of those strokes is doing useful work on the shell. This tool runs the arithmetic both ways: hand it a split with a rate and it returns the metres covered per stroke; hand it a DPS with a rate and it returns the split that combination produces. No spreadsheet, no guesswork in the boatshed.
Working out DPS from rate and split on a Concept2
Take the boat speed in metres per minute (500 divided by your split seconds, multiplied by 60), then divide by the stroke rate. A 1:50 split moves the shell 273 metres a minute. At 24 spm that lands at 11.36 metres per stroke. Lift the rate to 30 spm and hold the same 1:50 and DPS collapses to 9.09 metres per stroke. Identical boat speed, materially more effort spent moving the handle. NZ coaches at Auckland Rowing Club, North Shore Rowing Club and Waikato Rowing Club lean on DPS precisely because a rower cannot fake it by rating up the way a split number can be padded.
Inputs
UT2: 18-20 spm. UT1: 22-24 spm. AT: 26-28 spm. TR: 30-34 spm. AN: 36+ spm.
Typical adult range 7-14 metres per stroke depending on rate and fitness.
UT2: 18-20 spm. UT1: 22-24 spm. AT: 26-28 spm. TR: 30-34 spm. AN: 36+ spm.
At this pace and rate
Rate, split and DPS bands across the five training zones
Indicative rate, split and DPS triples for a Kiwi club rower whose race pace sits at 1:50 over 2k. Slide your own 2k split in and the numbers shift in lockstep.
| Zone | Rate | Typical split | DPS (m) |
|---|---|---|---|
| UT2 (steady aerobic) | 18-20 spm | 2:00-2:10 | 12.5-13.9 |
| UT1 (firm aerobic) | 22-24 spm | 1:55-2:00 | 10.4-11.8 |
| AT (threshold) | 26-28 spm | 1:50-1:55 | 9.3-10.5 |
| TR (race pace) | 30-34 spm | 1:40-1:50 | 8.0-9.1 |
| AN (anaerobic) | 36-44 spm | 1:30-1:40 | 6.8-7.7 |
Method behind the numbers
The arithmetic, written out longhand
Start from boat speed: 500 / split_seconds returns the strokes-per-second of the flywheel equivalent, multiplied by 60 gives metres per minute. Divide that by stroke rate to land on DPS. The inverse: split_seconds = (500 x 60) / (DPS x stroke_rate). Shell speed in metres per minute always equals DPS x rate. Given any two of split, rate and DPS, the third drops out of one line of maths.
Rate without DPS is wasted motion
Rate by itself only tells you how fast the slide is moving. Split tells you how fast the shell is moving. DPS sits between them and tells you how much of the rate is actually translating into hull speed, which is the closest thing the erg offers to a measurement of stroke length and ratio. Two Kiwi athletes pulling 1:50 at 24 spm share the same DPS (11.36m). Bump one of them up to 28 spm at the same 1:50 and DPS falls to 9.74m. Same boat speed, around 17 per cent more strokes per kilometre, considerably worse ratio. That is the gap where a coach plants the drill block. Pair this tool with the training pace calculator for rate-anchored zone targets, or the erg pace calculator when you need watts and projected finish times alongside the split.
Why DPS reads differently in the shell than on the erg
Out on the water the gap between strokes is real glide, not flywheel deceleration. Hull speed bleeds away unevenly depending on rigging, blade work, wind on Lake Karapiro or chop on Lake Ruataniwha, and how well the crew is matched at the catch. Mismatched DPS inside an eight or a four is the fastest way to wash speed off a boat that is otherwise fit enough to win. NZ coaches monitor on-water DPS via NK SpeedCoach units and stroke meters, applying the same formula above. Expect on-water DPS at any given rate to come in roughly 10 to 15 per cent under the erg figure at comparable effort, because hulls do not decelerate in the predictable, repeatable way a Concept2 flywheel does.
Frequently asked questions
What DPS should a NZ club rower be hitting?
Openweight men in good shape sit around 11 to 13 metres per stroke at steady-state rates (18-22 spm) and drop to 8 to 10 metres at race pace (32-36 spm). Lightweight athletes and women typically run 10 to 15 per cent shorter across every rate because absolute stroke length scales with body proportions, not just fitness. Anything below 7m per stroke at any rate is the calling card of a stroke quality issue: usually a short catch position, an early back swing before the legs finish, or a rushed recovery that clips the next entry.
How do I add metres per stroke without rating down?
Two levers do most of the work: arc length at the catch and full leg drive before the back opens. A longer arc moves more water; an early back swing throws away the strongest phase of the drive. Then guard the recovery, because a hurried slide automatically shortens the next catch. NZ coaches commonly post a DPS target on the board for a 20-minute UT2 block at 18-20 spm and ask the crew to hold that number as rate climbs into UT1 and AT. The block fails the moment DPS drops below the target as rate lifts.
Does my erg DPS match my on-water DPS?
No, and the two should be tracked as separate metrics. Erg DPS depends on flywheel inertia and your stroke arc against a fixed seat platform. On-water DPS depends on hull glide, blade entry angle, run between strokes and crew synchronisation. At equal effort the erg value usually runs 10 to 15 per cent higher than the on-water value because the flywheel sheds speed predictably while a hull moving through water does not. Treat the erg figure as a personal benchmark and the boat figure as a crew benchmark; do not try to convert between them.
Why does my DPS sink the harder I push?
Almost always because rate climbs ahead of power. When a rower chases a faster split by lifting the rate, recovery time compresses to fit the cadence and each stroke gets shorter, so DPS falls even as the screen number drops. Durable speed gains come from extra force per stroke at the same rate, which holds DPS steady or improves it. Then fatigue compounds the effect: as lactate builds the catch shortens and the finish lifts early, and both shave metres off every stroke at exactly the moment you can least afford it.
What stroke rate should a NZ rower run at race pace?
Senior openweight men typically race 2k in the 32 to 36 spm band, openweight women 30 to 34 spm, lightweights and juniors 30 to 34 spm. Holding higher than that without the DPS to back it up is the textbook way to burn through your aerobic ceiling inside the first 500m. Kiwi coaches preparing crews for the Maadi Cup, the NZ Rowing Championships or Bond Cup selection generally cap opening rate at the lower end of those bands and add rate only as the field starts moving on the second 500. The training pace tool surfaces zone-specific rate targets pegged to your personal 2k split.
Does lifting the rate change my watt output?
No. Concept2 watts depend only on split, via watts = 2.80 / (split/500)^3, which has no rate term in it. In practice though, holding a given split at a lower rate forces more force into each individual drive, and each individual drive sits closer to your maximum, so it is harder to sustain over a full piece. Lower-rate rowing with strong DPS is usually more metabolically efficient at submaximal paces because the total stroke count across the piece is lower and the cumulative recovery work shrinks.
More tools in the Aotearoa erg suite
Training Pace Calculator
Rate, split and interval setpoints across UT2, UT1, AT, TR and AN, anchored to your 2k pace.
Erg Pace Calculator
Convert split into watts and per-hour kcal, project 2k, 5k, 6k and 10k finishing times.
Drag Factor Calculator
Pick a damper setting and drag factor matched to your bodyweight, experience and the test piece.
Watts to Split Converter
Take any wattage to a 500m split, or any split back to watts.
One rower with a calculator is arithmetic. A whole Maadi squad is a system.
Row HQ stores split, rate and DPS against every athlete and every piece automatically, so coaches across Aotearoa see the efficiency trend across a Karapiro winter block, not just the splits on test day.