Formula One racing star Michael Schumacher remained in critical condition Monday after a skiing accident, with doctors saying they are working “hour by hour.” “We cannot predict the future for Michael Schumacher,” said Grenoble University Medical Center chief anesthesiologist Jean-Francois Payen. Schumacher is in a medically induced coma after hitting his head on a rock while skiing. Schumacher was wearing a helmet, but doctors said it clearly was not sufficient. “Someone who had suffered this accident without a helmet would not have made it this far,” Payen said. Trauma surgeon Gerard Saillant, a friend who operated on Schumacher when he injured his leg in 1999, said Schumacher’s age—45—and fitness should help him.