What kind of brace should i use when i run at school if i have osgood schlatters disease?

Brace doesn't help: Much in this situation. Best options are rest, ice, elevation, and as much activity as possible on a soft surface like turf instead of a basketball court.

No brace. Stretch &: Stretch. Specifically the quads and rectus femoris. Osgood-schlatter is a condition involving a portion of the tibial growth plate at the insertion of the patellar tendon. It resolves when the growth plates close. It tends to occur around the pubertal growth spurt and the best treatment is stretching multiple times a day, with a good mix of ice and nsaids as needed.