The pilot of the balloon located a landing area after completing a racing event. The pilot stated that he briefed the passenger prior to the landing, to hold on to the basket handles. The pilot positioned himself in the front of the basket, with the passenger behind him. The landing was a normal, "stand-up landing." The passenger lost her grip from the handles and she consequently pitched forward as they bumped the ground and came to a stop. The passenger complained that her ankle hurt as she exited the basket. At first it was believed the passenger suffered a sprained ankle. A medical evaluation, 2 days later, discovered a fracture above the ankle.