The ball crew is one of the most coveted jobs in tennis, and it’s just as competitive. This year, 3,500 people applied to be part of the U.S. Open ball crew, but only 130 were selected to work alongside some of the world’s top tennis players. The good news, though, is that anyone 14 and older can apply and try out for the team. TIME went behind the scenes to see what it takes to make the cut.