Pietrosimone, however, was part of a group that did a systematic review of all studies on whether knee braces prevent injury in 2008 and concluded that the issue was not so clear-cut. The methodology of the studies was flawed in many cases, the review found, and several studies even indicated that wearing braces might increase — not decrease — the risk of knee injury.

With a custom pair of braces costing upward of $1,000, the amount of money a program spends on outfitting all of its “high-risk” players — generally seen as linemen, some tight ends and some linebackers — is significant. Yet in a copycat sport, the lack of a medical consensus has not stopped the movement from spreading.

“There was actually a similar systematic review done more recently by a different group, and they came up with the same answer,” Pietrosimone said in an interview. “In some ways, it has become like taping ankles. Just about everyone wraps tape on players’ ankles prophylactically, and there is, in reality, very little evidence to support doing that.”

Such trends are not uncommon in sports: The use of kinesio tape increased exponentially after the 2012 Olympics, when many beach volleyball players were seen using it, and Michael Phelps helped popularize the ancient Chinese healing practice of cupping during the 2016 Rio Games.

Prophylactic bracing among college linemen, however, is hardly a fad. Danny Poole, who is Clemson’s director of sports medicine and has been at the university for more than three decades, estimated that he began endorsing the practice 15 years ago. (Clemson also requires players to have either tape or a brace on their ankles.) Poole said he was largely indifferent to skepticism that might appear in academic journals, preferring a more direct evaluation.

“I’m not a big, huge studies guy,” Poole said. “I like to hear from the players. And the first time you hear, ‘That brace saved me today,’ you know it’s doing something.”

In interviews with several players, coaches and trainers here for the national championship game, many cited instances when they had found a brace bent from a heavy blow and said they shuddered to think what might have happened to the knees inside those braces if there had been no protection. Yet four of the six players could also recall instances when they, or a teammate, had sustained a serious injury despite wearing a brace.