After a 50-minute, late afternoon balloon flight, the pilot executed a normal touch down onto a flat grassy area. A weather station 8 miles to the northeast reported the surface wind was five miles per hour at the time of the accident. All of the occupants were facing forward for the touchdown and the pilot had previously instructed both passengers how to hold on to two points and how to flex their knees for the first impact of landing. At the first impact with the ground, the 82 year old female passenger sank to the floor of the balloon basket. It was immediately apparent to the other passenger that she had been injured. After the basket stopped moving, the pilot deflated the balloon and the pilot, the other passenger, and a bystander assisted the injured passenger in exiting. The injured passenger was transported to the hospital and treated for a broken leg. The other occupants were not injured and the balloon was not damaged. The uninjured passenger said the pre-takeoff safety briefing and the before landing safety briefing were simple and clearly understood.