Studies do indeed show the greatest chances of injury to skiers occur in the afternoon. It's also true that injuries to football players are higher in the third quarter of a game. Coincidence?

Researchers don't think so. They say general fatigue in athletes may be the key factor in these injuries. Fatigue leads to a decline in knee proprioception. Proprioception is the joint's sense of position. Fatigue and then decreased proprioception can result in ligament injuries.

Change in neuromuscular control may be a factor, too. This is the link between messages to the nerve telling the muscle what to do and when to do it. Special exercise to improve motor control may help reduce these "third quarter" injuries.