Stroke Rate: The Cadence Number That Doesn't Equal Boat Speed

Definition and units

Stroke rate is expressed in strokes per minute (spm). One stroke is one complete cycle: catch, drive, finish, recovery. A crew rating 34 spm completes 34 full stroke cycles every 60 seconds. The number is purely a cadence measurement - it says nothing on its own about how fast the boat is actually moving.

Cox boxes, ergometer monitors and GPS units all display rate live, updating every few strokes. Most current units show rate to one decimal place - 34.2 spm - though whole numbers are typically used when calling rate during training. Coaches and coxes work in whole numbers; the readout is rounded mentally to the nearest spm in the field.

How stroke rate is measured

In a coxed shell, a magnetic sensor on the stroke seat's slide fires each time the seat reaches the front stop. The cox box counts those pulses and displays the rate in real time. Coxes at clubs across Aotearoa - from Hawkes Bay RC on the Tukituki to Otago RC on the harbour - use the readout to confirm the crew is on the target rate during each piece.

On an ergometer the rate is derived from flywheel and chain pull timing rather than a slide sensor. The Concept2 PM5 monitor shows rate alongside split, watts and calories through every session, and the long pulldown of an erg test is the most common environment where rowers actually watch their own rate live.

GPS units such as the NK Speedcoach can infer rate from the hull's velocity trace - the boat surges forward on each drive, and individual strokes show up as repeating peaks in the speed graph even when no slide sensor is fitted. Useful for singles, doubles and pairs where no cox box is in the shell.

Typical stroke rates by training type

Standard training and racing rates used at NZ club and national level:

• UT2 (steady state): 18-22 spm. The long aerobic base that forms the foundation of winter training volume for crews on Lake Karapiro, the Avon, the Whanganui River and waterways across Aotearoa.
• UT1 (firm aerobic): 22-26 spm. Higher quality aerobic work that lifts lactate threshold.
• AT (anaerobic threshold): 26-30 spm. Threshold pieces, sustained race-pace efforts.
• Head race pace: 28-32 spm. The settled rate over the 4-7km of head racing on courses like the Head of the Waikato or the Head of the Harbour in Auckland.
• Regatta race pace: 36-40 spm. The rate crews hold through the body of a 2km race at the Maadi Cup on Lake Karapiro, the NZ Championships at Lake Ruataniwha or the North and South Island Championships.
• Sprint or start: 40-44 spm. The burst rate crews push through the first 20 strokes off the line and the final 250m of a 2km race.

Junior and club crews typically race 1-2 spm below senior national crews in equivalent boat classes. Robbie Manson, NZ's former world record holder in the single, demonstrated how elite scullers carry high distance-per-stroke at controlled rates rather than spinning at higher cadences with shorter strokes. Use the free training pace calculator and erg pace calculator to turn pace targets into splits and training rates.

Drive-recovery ratio

Every stroke has two phases: the drive (blade in the water, applying power) and the recovery (blade clear, sliding back to the catch). The proportion of each shifts with rate.

At base training rates (18-22 spm) the recovery is two to three times longer than the drive - a 1:2 or 1:3 ratio. The crew has space to set each catch cleanly. At race rate (36-40 spm at the Maadi Cup finals on Lake Karapiro or the NZ Championships at Lake Ruataniwha) the recovery compresses sharply and the ratio approaches 1:1. The crews that hold a long, deliberate recovery at race rate carry more hull run between strokes and outrun the ones who collapse it under fatigue.

How rate affects boat speed

Stroke rate and boat speed connect through distance per stroke (DPS). DPS = boat speed divided by stroke rate. A crew can reach the same hull speed at a lower rate by making each stroke longer and more powerful (high DPS), or at a higher rate with shorter strokes (lower DPS but more frequent power application). The trade-off depends on the crew's power profile, technique and conditioning.

Above roughly 40 spm for most crews, extra rate starts to cost boat speed because the recovery is too short to load the catch with full force on every drive. The boat slows down rather than speeding up. Coaches find each crew's optimal race rate empirically through timed pieces at different cadences - that rate is what they target on race day, not the highest number the crew can physically hit.

Training rate progressions

Rate ladders are a cornerstone of NZ club training. The crew rows 5 minutes at 18 spm, 5 minutes at 20, 5 at 22, 5 at 24 - building familiarity with each rate that will appear in racing. Rate-locked pieces (such as 4 x 1km at 32 spm) develop the crew's ability to lock and hold a target rate under fatigue, which is what separates a clean race plan from a ragged one.

Stroke seats and coxes use the cox box to verify the rate is accurate through each piece. Crew lineup and session planning tools let coaches assign rate targets per piece before the session, and the cox confirms execution from the cox box display while the crew is on the water.