A high school football rule was intended to reduce head injuries. Researchers have discovered a totally different benefit

A high school football rule, introduced 12 years ago to reduce serious head injuries among players, has had an unintended benefit: fewer leg injuries.

The nationwide rule banned American football players from hitting opponents above their shoulders, in an effort to protect their heads. Head impacts in football have become an increasing concern for players and their families because of recent studies tying head injuries to CTE, a progressive brain disorder that raises the risk of dementia.

But new research shows that the high school rule is having an impact in an unexpected way. Emergency room data showed there were decreased numbers of lower body injuries among high school players.

The researchers were surprised because they had feared lower body injuries would increase with the regulation that reduces tackles to the upper body.

“We were just thinking as people are avoiding the head and neck, they’re going to be tackling lower in the body, so maybe the injury burden might be getting shifted lower in the body,” Nolan Tanji, a University of Hawaiʻi at Mānoa’s John A. Burns School of Medicine student, said in a statement.

However, it was not all good news - there were more collisions between players after the rule than there were before.

The researchers hope further data will be able to shed light on why that’s the case.

Tanji and his classmates examined more than 14,000 ER entries of athletes aged 14-18 from five years before the rule’s implementation and five years after it took effect.

The data showed that there was a yearly average of 7,315 lower-extremity injury cases before the rule and only 5,611 afterward.

Using those cases to estimate the same drop nationwide, the researchers said these injuries plummeted from an average of 242,000 before the rule to 193,000 injuries after the rule.

There were also fewer knee injuries after the rule took effect.

“It’s not completely safe but, you know, it’s looking promising for the future in terms of injuries in football,” Tanji noted.

The findings suggest that the rule is more beneficial than previously believed and there has been a decrease in neck injuries since 2014, separate research uncovered in 2022.

However, the researchers say that the rule cannot necessarily be credited for causing the decline.

Changes in training, injury prevention and equipment technology may have all played a role, the researchers suggest.

And the database also only included injuries treated in emergency departments and there was no way of knowing which positions the injured athletes played.

Running backs that rush the ball and linemen that protect the quarterback are the most likely to receive hits, 2011 research from Brown University found.

Football is one of the top sports for head injuries, federal data shows, with tackling responsible for 63 percent of concussions.

There are an estimated 100,000-150,000 concussion cases linked to high school football each year, according to the Athletic Equipment Managers Association, though around half of all concussions are unreported.

Repeated concussions can lead to CTE, also known as chronic traumatic encephalopathy, Boston University researchers say.