Then see if your beginners stay.
White belts are the core of every gym's membership and up to 80% of its recurring revenue. About half of them leave within the first 90 days, and nine in ten never reach blue belt. Each one who goes takes his fees with him.
At $150 a month, a white belt who leaves in month four instead of month ten is $900 gone. Keep five of them six months longer and that is $4,500 a year from people you already signed. Industry data, not ours.
Underhook is an educational app for jiu-jitsu: a decision trainer. Ten minutes a day of "what do you do from here?" situations along the white-to-blue path, on iPhone and Android, in English and Spanish.
Each answer builds the link between a position and the right move, so the lesson shows up on the mat, not just on the screen. Short daily sessions, active recall, spaced repetition, visible progress.
A typical instructional costs over $100, runs over two hours, and almost nobody finishes it. Underhook turns the same material into something your beginners will actually open on a Tuesday night. It competes with nothing you sell.

On our side. No codes, no setup, nothing for the front desk. Your members pick your gym when they sign up and get full access.
One message in the club chat and a QR poster at the front desk. We send you the message template and the poster file, ready to print.
How many of your beginners started, how many kept going, and the positions they struggle with most.
Anyone who wants to keep going pays the regular price in the app: about $8 a month or $50 a year.
The gym never pays anything.
Give it to your beginners, tell us what breaks, and let us measure whether they stay. No call needed.
Oleksii Vasyliev, Underhook, Barcelona
hello@underhook.xyz · WhatsApp +34 613 156 187 · underhook.xyz