The accident was caught on video.
The floor splintered and impaled the player in her stomach.
>>Click here to see the video
Perry Hibner, who was running the basketball tournament, told WISC that he had never seen anything like it.
"It was 3 to 4 inches long and in some parts, maybe a quarter to a half inch deep," Hibner said.
People were asked to leave the gym as emergency crews worked to get her onto a stretcher and out of the gym.
The splinters amazingly missed all of the player's internal organs.
She had to undergo surgery to make sure there were no serious injuries.
The broken board was glued and taped, with garbage cans marking it, WISC reported.
It is expected to be fixed this week.