Freestyle · technique analysis from video

See the technique faults in your swim video, frame by frame

Open a side-view swim video; the program extracts the swimmer's skeleton, measures common faults from low hips to kicking from the knee, and lists each one with a suggestion and the frames where it shows most.

Download for Windows What does it measure?
  • Free
  • No installation
  • Your video never leaves your computer

Illustrative screen with sample values — the app interface is in Turkish.

What does it measure?

It computes the seven faults that cost the most speed in freestyle from the skeleton keypoints. Each measurement has a threshold; cross it and it is listed as a fault.

Low hips

How far the shoulder-to-hip line tilts below horizontal. When the hips drop, the body pushes water instead of slicing through it — the biggest source of drag.

Ideal< 12°

Sinking legs

The tilt of the line from shoulder to ankle. The further the feet sit from the surface, the more the legs act as a brake.

Ideal< 15°

Head position

How far the head lifts above the body line. When the head comes up, hips and legs drop like a seesaw.

Ideal< 30°

Kicking from the knee

The tightest knee angle during the kick. If the kick comes from the knee rather than the hip (“bicycle kick”), the shin meets the water square-on and thrust drops.

Ideal> 115°

Bending at the hips

The shoulder–hip–knee angle. If the body folds at the hips instead of holding a straight line (“sitting position”), the thighs face the water.

Ideal> 150°

Kick width

Ankle separation relative to torso length. When the feet leave the body's shadow, drag goes up.

Ideal< 1 torso length

Arm extension

Elbow angle when the arm is furthest forward. Starting the pull the moment the hand enters shortens the stroke.

Ideal> 145°

Stroke rate

Stroke cycles per minute (one arm), taken from the arm's back-and-forth motion. Reported as information, not as a fault.

Unitcycles/min

For every fault you get its severity (mild · moderate · severe), the measured value, why it matters, a suggestion and drill to fix it, and the three frames where it is most visible.

How does it work?

Four steps; no account, no uploading your video anywhere.

Open the video

Pick it with Video Aç (Open Video) or drag the file onto the window.

Press Analiz Et

Depending on the computer, about one minute for every 10 seconds of video. The same video opens instantly the second time.

Review the faults

Click a timestamp in the list and the video jumps to that frame. 0.25x slow motion; Space play/pause, ← → frame by frame.

Save the report

Rapor Kaydet (Save Report) produces a single-file HTML report you can send to your coach as is.

Everyone in the lanes, separately

If there are several swimmers in the video, each is tracked and analysed separately. Numbers run from the lane nearest the camera outward; each swimmer is drawn in their own colour.

Your video stays with you

The analysis runs entirely on your own computer. The program sends nothing to the internet and needs no connection.

Free, nothing to install

Extract the zip to a folder and run it. No account, no licence key, no trial period.

Filming tips for good results

The measurement is only as good as the footage. The clearer the skeleton is visible, the more reliable the result.

  • Film from the side. Keep the swimmer's whole body in frame.
  • Underwater or at water level if you can. From above the surface the legs are hidden by splash and water, so knee and kick measurements stay rough.
  • Make the swimmer large in frame. Small swimmers in far lanes may not be tracked.
  • At least 1080p, steady camera. Keep the camera as still as you can.
  • Keep the view clear. Nothing can be measured while a post or a person is in front of the swimmer.
  • Freestyle only for now. Measurements are not meaningful for other strokes.

Download and try it now

One zip file. Extract it to a folder and double-click YuzmeAnaliz.exe; the skeleton models are inside the package, nothing is downloaded on first run.

Swimmer Analysis — Windows

Portable build for Windows 10 / 11 (64-bit). The file is large, so download it on your Windows computer.

Version 1.0 · 423 MB ·
Download for Windows

Requirements

  • Windows 10 / 11, 64-bit
  • About 650 MB of free disk space
  • No internet needed; no installer or admin rights either
  • Interface language: Turkish

In the package

  • YuzmeAnaliz.exe — the program
  • modeller — skeleton extraction models
  • OKUBENI.txt — short user guide (Turkish)
  • LISANSLAR.txt — open-source components

Important: Measurements are computed from a skeleton extracted automatically from the video and are approximate; they can be wrong. The program does not replace a swimming coach. Judge the findings by looking at the frames it points to, on your own or with your coach. The program is provided as is, without any warranty.

Frequently asked

What people most want to know before downloading.

Is it really free?

Yes. No fee, no account, no licence key and no trial period.

Is my video uploaded to a server?

No. The analysis runs entirely on your own computer; the program sends nothing to the internet and works without a connection.

Why does Windows show an “unknown publisher” warning?

Because the program is not digitally signed. Windows and browsers flag every new unsigned program this way. In the warning window choose More info › Run anyway; only download the file from this site.

Which strokes does it work with?

For now it is designed for freestyle only. The thresholds and fault definitions are freestyle-specific.

Will footage shot from above the water work?

It will, but the legs are hidden by splash and water, so knee and kick measurements stay rough. The best results come from side-view footage shot underwater or at water level.

How long does the analysis take?

It depends on the computer; about one minute for every 10 seconds of video. The result is cached, so the same video opens instantly the second time.

Does it run on Mac or on a phone?

For now it runs only on Windows 10 / 11 (64-bit).

Support the project

Swimmer Analysis is free and will stay free. If it helped you, you can chip in through GitHub Sponsors, one-time or monthly.

Sponsor on GitHub Donations are entirely optional; every feature is open to everyone. Payment is by card through GitHub and requires a GitHub account.

Film your next session and see for yourself

Free · Windows 10 / 11 · your video never leaves your computer

Download for Windows