College football players suffered far more concussions during practices than they did in games, medical researchers reported, a finding certain to add to the debate about regulating training regimens.

Much less clear is whether the college sports industry will nationalize safety reforms like those adopted by the NFL, which limits the number of full-contact practices per season.

The authors of the study, published in JAMA Neurology, found that 72% of the concussions they reviewed over five college football seasons happened during practice. And although preseason training accounted for about one-fifth of the time the researchers studied, they found that nearly half of the concussions occurred during that period.

Changes to the rules that govern games, they wrote, "are an important component to protecting athletes during competition," but they asserted that revisions to training activities before and during the season "could lead to a substantial reduction" in concussions.

"The biggest surprise was the extent of the data, not just the trend of the data," said Dr. Michael A. McCrea, the study's lead author and a professor of neurosurgery at the Medical College of Wisconsin.

In an editorial also published in JAMA Neurology, two other experts described the study's findings as "shocking."

"Concussions in games are inevitable, but concussions in practice are preventable," wrote the experts, Dr. Robert C. Cantu and Christopher J. Nowinski.

Mark Emmert, the NCAA's president, said the findings "provide new information for our members to modify rules while continuing education efforts."