BEAVER CREEK, Colo. — The fact that Michael Schumacher was wearing a helmet when he sustained a life-threatening head injury while skiing in France on Sunday probably did not come as a surprise to experts who have charted the increasing presence of helmets on slopes and halfpipes in recent years. The fact that the helmet did not prevent Schumacher’s injury probably did not surprise them, either.

Schumacher, the most successful Formula One driver in history, sustained a traumatic brain injury when he fell and hit his head on a rock while navigating an off-piste, or ungroomed, area at a resort in Méribel, France. Although he was wearing a helmet, he sustained injuries that have left him fighting for his life in a hospital in Grenoble, France.

Schumacher’s injury also focused attention on an unsettling trend. Although skiers and snowboarders in the United States are wearing helmets more than ever — 70 percent of all participants, nearly triple the number from 2003 — there has been no reduction in the number of snow-sports-related fatalities or brain injuries in the country, according to the National Ski Areas Association.

Experts ascribe that seemingly implausible correlation to the inability of helmets to prevent serious head injuries like Schumacher’s and to the fact that more skiers and snowboarders are engaging in risky behaviors: skiing faster, jumping higher and going out of bounds.