The Navajo teenagers scamper out of the locker room as if their feet are on fire.

The Window Rock High School Fighting Scouts sprint across the arena floor, bounce up and down as if they are jumping invisible ropes and sprint to the hoops for layups.

Neither the Scouts nor their archrivals, the Chinle High School Wildcats, will stop running until the final buzzer sounds. These teenagers — most are well short of 6 feet — will weave and cut, press full court and rain 3-point shots.

This is rez ball, a Roadrunner, beep-beep blur of legs and arms and sneakers. The former N.B.A. coach Mike D’Antoni’s claim to fame is that his Phoenix Suns tried to shoot within seven seconds after getting the ball. Navajos, who adore long-distance running and run-and-gun hoops, would view that as a slowdown offense.

Reservation basketball takes the form of obsession here. Baskets made of wire and garbage pails and small tubs hang off homes and garages and wooden poles anchored in patches of red dirt. Window Rock and the nearby town Fort Defiance have about 6,000 residents. Beyond, the land of the Dine encompasses winding canyons and washes, forests and desert, isolated towns and hamlets filled with the traditional sacred dwellings known as hogans.

A knife-sharp wind pushes a veil of snow down off the high buttes this night. I turn my car into Window Rock High School two hours early and wonder if anyone will show up.

As it turns out, hundreds of snow-dusted pickup trucks sit in the parking lot. Inside, the joint is packed, 4,500 strong: Navajo grandmothers wrapped in traditional blankets, young granddaughters in jeans fiddling with iPhones. Boys in team jerseys ogle the girls, who strive to appear oblivious.