Panting uncontrollably, a group of basketball players lean over, their hands on their knees.
Countless trips up a 55-degree, 116-step wooden spiral staircase in San Francisco cause more than just a few pearls of sweat.
Gripping the collar of his hoodie, Stanford guard Anthony Goods tilts his head back, gasping for air.
"Man," Goods says, "this is crazy."
Goods is one of the dozens of top-flight basketball players who come to San Francisco to train with a guru the outside world knows little about. His clients have included the Wizards' Gilbert Arenas, the Celtics' Leon Powe and the Pacers' Kareem Rush.
His name is Frank Matrisciano.
