The old blue court at Miller Park had seen better days, and so had Leo’s sneakers. The rubber soles were smooth as glass, and his last sprint for a cross-court volley had ended in a spectacular, undignified slide.

"These," Toby said, tapping a neon-yellow pair, "are built for the baseline grinders. They’ve got lateral support like a tank."

"Time for an upgrade," his doubles partner, Sarah, said, pointing at the flapping fabric of his right toe. "Unless you're planning on ice skating next Tuesday."