ALAMEDA, Calif. — On a picture-perfect East Bay afternoon — 75 and a clear blue sky — a few top players for the Evil Geniuses were holed up in the Lair.

Preparing for a qualifying match, a StarCraft prodigy named HuK was sitting in one of the gaming rooms, communing with his monitor and limbering his fingers on a keyboard. Down the hallway, his teammate DeMusliM was running through a replay of his own last match and working on his manual dexterity, swirling a pair of worry balls in his hand.

It was 3 p.m. and the California sunlight was beating at the windows, but the Lair’s front shutters were drawn tight, leaving the gamers to focus in the darkness on their training, which meant playing video games from dawn to dusk each day, or from dusk to dawn each night. Their physical needs had been seen to: the kitchen refrigerator was stocked with bagels, the living room cooler with caffeinated sports drinks. At their flashing terminals, the four young men were immersed enough in work that they hardly noticed the two maids feather-dusting everything around them — and occasionally poking a vacuum cleaner between their legs.

Like sports stars everywhere, professional-level video gamers need a place to practice, and for the high-tech athletes of the Evil Geniuses — the Yankees of the video gaming world — that place is the Lair, a sock-strewn tract house on an ordinary side street in this breezy island city east of San Francisco. With its redundant Internet connections and eight-to-a-toilet dormitory rooms, the Lair is a clubhouse and a crash pad: a residential exercise space where digital Derek Jeters can roll out of bed and stumble downstairs for workouts in the gym.