See the stroke your eye can't quite catch.

Upload footage of a rower — single scull, erg, or one athlete in a crew boat. Catchline finds the athlete, frames them, tracks their joints, and reports what it can see. Rough footage still gets a report; it just tells you how much to trust it.

CATCHDRIVEFINISHRECOVERYCATCHDRIVEFINISH

Drop a video, or click to choose one

Any video your browser can play — phone footage, portrait or landscape, any angle.
Side-on and steady gives the best numbers, but everything gets analyzed.

Catchline will find and follow the athlete on its own.

Step 1

Framing

Catchline will locate the rower and follow them automatically. Drag a box only if you want to override that — useful when several athletes are in shot.

Frame preparation

These run on each frame before tracking. Leave them on unless you're comparing results.

Find and follow the rowerLocates the athlete, crops in on them, and moves the crop with them through the clip. Handles panning cameras and rowers who cross the frame. Auto-correct exposureMeasures brightness and contrast, then lifts dark, flat, or backlit footage before tracking. Mirror horizontallyOnly affects the picture, not the numbers. Handy when comparing a port and starboard rower side by side.

Step 2

Tracking joints across the clip

Loading pose model…

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Report

Stroke analysis

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Stroke rate (spm)

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Strokes detected

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Drive : recovery

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Tracking quality

0.0s

Knee angle over time

Troughs are catches, peaks are finishes.

tracked estimated catch finish

Coaching notes

How to read this: the thresholds used here are provisional placeholders — they have not been validated against graded footage, they are not calibrated to this athlete, and they take no account of body type or boat class. Joint angles are measured in the image plane, so a camera that isn't square-on to the rower will compress them — check the framing note above before treating any number as a verdict. Blade and oar mechanics aren't tracked; this covers body position and timing only.