The rowing stroke, phase by phase

On the drive, the legs, then the back, then the arms. On the recovery, the reverse: hands, then body, then knees. Most technique faults are a break in that order, or a bad position at one of the two ends of the stroke, the catch and the finish.

Throughout this guide, the figures show one real stroke from an erg session Mocta-X graded: an A, 97. It's a good stroke, not a perfect one, which makes it a useful example.

The catch is where the blade goes in and the drive starts. A good catch position lets the legs push straight away, without the body having to rearrange itself first.

On the example stroke, the grader measured forward body angle at 18.6°, shin angle at 2.9°, arm extension at 159.7° and knee compression at 35.5°. All four were inside its targets for the recreational style.

• Forward body angle. The trunk leans forward from the hips, not by rounding the back. Sitting too upright shortens the stroke; lunging past it overloads the lower back. It's the heaviest check at the catch.
• Shin angle. Shins come up to about vertical. Pushing past vertical (over-compression) puts the knees and hips in a weak position to start the drive.
• Arm extension. Arms are long at the catch. Bent arms mean the arms start pulling before the legs, which disconnects the stroke.
• Knee compression. How deeply the knees are bent at the catch, which sets how much leg drive is available. Read it together with shin angle.

The drive is where the power goes in, and sequencing matters more here than anywhere else. That's why the drive sequence is the heaviest of all 13 checks.

• Drive sequence (legs → back → arms). The legs start the drive, the back opens as the legs finish, and the arms draw in last. Opening the back early, or pulling with the arms early, wastes the legs and is one of the most common faults on the erg.
• Leg–back connection. The handle should move as soon as the seat does. When the seat moves and the handle doesn't, that's shooting the slide: the legs push, but the back isn't holding the load, so the effort doesn't reach the handle.
• Handle path. The handle should travel level between the catch and the finish. On the erg that's graded; on the water it isn't, because the handle correctly moves in an arc around the pin.

On the example stroke, the grader measured layback at 36.6° and trunk swing at 55.2°; both passed. But knee extension at the finish read 151.3°, short of fully down, so it flagged leg extension. That's the kind of detail that's hard to see live and easy to see measured.

• Layback. A controlled lean back past vertical at the finish. Too little shortens the stroke; too much makes the recovery hard to start and loads the lower back. The right amount depends on the style, so a sprint crew and a recreational rower are graded against different targets.
• Leg extension. The legs should finish their drive before the back and arms complete the stroke. Legs still pushing at the finish usually mean the back and arms took over too early.
• Trunk swing. How far the trunk travels through the stroke, from catch lean to finish layback. It's the lightest-weighted check, but useful for spotting a short stroke.

• Recovery sequence (hands → body → knees). Hands away first, then the body swings forward from the hips, and only then do the knees rise and the seat moves. Knees up too early means the hands have to lift over them.
• Body set. Once the body has swung over, the trunk should stay where it was set all the way up the slide, rather than drifting or lunging on the way to the catch.
• Slide rhythm. The recovery should take noticeably longer than the drive, with a target ratio of around 2 : 1. Rushing up the slide is the fastest way to spoil a good drive, and it's common as rate rises.

Measurement tells you which fault to work on. These are standard drills coaches use for each one. Film a few strokes before and after, and the numbers will show whether the drill transferred.

A good stroke on its own isn't the goal. The goal is the same good stroke at 1,500 m as at 200 m. Mocta-X's performance score measures that: consistency (how tightly your positions cluster and how well you hold rate), durability (how far your positions drift over the piece, and where they broke), and efficiency (sequencing, connection, handle path and rhythm).

Each of these checks can be measured from a side-on phone video: a pose model places the joints on every frame, and the angles and timings follow from them. How to film rowing covers the set-up, and rowing video analysis shows what comes back. The references behind the targets are Kleshnev's BioRow data, Egan-Shuttler et al. (2013), and Concept2 and British Rowing technique guidance.