Austin Gray, 22, sat semi-cross-legged on a chair inside Warrior Playground gym Tuesday afternoon, stretching out leg muscles pushed to their limit by a day of training at the gym’s makeshift “American Ninja Warrior” obstacle course. Gray had gleefully ditched his shirt moments before to cool off, displaying three small scars on his stomach that create a triangle. Gray made his television debut last week on “American Ninja Warrior,” during the Minneapolis Qualifiers episode.