COPPER MOUNTAIN, Colo. — Ted Ligety, the world’s top-ranked giant slalom skier, wrote a blog post over the summer that he called, “My thoughts on FIS’s attempt to ruin GS.”

Ligety, who was training with the United States ski team in New Zealand, had just skied for the first time on new giant slalom skis — straighter and longer than what he was accustomed to, with less side-cut, curve or shape. It was equipment that earlier in the summer ski racing’s governing body, the International Ski Federation, known as F.I.S., said would be mandatory next season. Ligety used a derogatory term to describe the new skis, which in essence are a kind of skis not manufactured in two decades, since the advent of parabolic skis.

“I felt like Phil Mahre circa ’84,” he wrote.

Ligety, winner of three of the last four World Cup giant slalom titles, has emerged as an outspoken opponent of the new rule. More than 80 percent of World Cup athletes feel the same way, and many have signed a petition saying so. Notable supporters of the change include the Austrian men’s ski team, and the Austrian ski manufacturer Atomic and French-based Salomon (of the same parent company, Amer Sports).

In announcing the rule change, F.I.S. cited studies of ski specifications and injuries, including one by the University of Salzburg in Austria. The new skis were “scientifically proven to enhance athlete safety and reduce risk of injury,” F.I.S. said in a statement.