Court Notes Padel
Bandeja or víbora? Even the players disagree.
Our hardest classification pair, and the 230-serve afternoon in Lisbon that finally separated them.
Ask two padel players to name the same overhead and you will start an argument. The bandeja and the víbora are cousins: both defensive-ish overheads, both played from the back, both designed to do a specific job to the ball rather than to win the point outright. Your wrist knows which one you played. Making a computer know took a Lisbon afternoon and a lot of labelled video.
01 — Why the pair is hard
The two shots share contact height, court position and outcome. The differences are small and early: the víbora loads the wrist earlier and rolls into contact with more sidespin shape; the bandeja stays flatter and later, a slicing shelf. Miss the first 180 milliseconds and the rest of the swing is identical.
02 — The afternoon that separated them
We took three club players, two courts and one coach with a clipboard, and recorded everything: 412 labelled shots, 230 of them serves, every rally annotated on video. Against that set the full eight-class classifier reached 0.91 F1 — and the bandeja–víbora pair, published honestly, sat at 0.78. The worst pair is the interesting pair. That is where the next month of work went.
03 — What we do while we improve
When the classifier is unsure between the two, PlayDNA says so: the swing lands in Review strokes with an uncertain badge, and you get the final word. Corrected shots stay yours; if you opt in, the anonymised correction is exactly the sample that teaches the next build the difference.