But very few high school leagues have caught up with that NFL standard.
Texas has. The state that brought you Friday Night Lights and a $60 million high school football stadium in Allen has adopted one of the strictest limits on high school contact and tackling at practices.
The University Interscholastic League, the association that sets rules for high school sports in Texas, limited full contact during practice to 90 minutes a week.
Just south of Dallas, DeSoto High School is home to one of the top football teams in the state. KERA’s Lauren Silverman recently visited a DeSoto High football practice and says she saw no head-to-head action or players falling to the ground after a tackle.
"This is a tackling circuit," explains DeSoto coach Paul Beattie. "The way we modified it is we're not going to take them to the ground. We don't want to hurt our own players."
In this type of tackling circuit drill, players run past, instead of into, each other. The team's head coach, Claude Mathis, welcomes the rule. "I saw a big improvement in our kids, in our kids' legs, in their body language. They weren't as tired as they were before," he says.
But players like DeSoto varsity linebacker Derion Woods are conflicted. "I mean, they do it to keep us healthy, but as a linebacker you do like hitting," he says.
Texas and Arizona both have rules limiting contact during high school football practice. But most states have no regulations.
Football is the most popular sport among high school boys, with more than 1 million playing the game during the 2012-13 school year. But the sport has taken a hit in recent years over allegations that the game is unsafe.
Young athletes across all sports suffer 300,000 concussions each year, according to researchers from Nationwide Children's Hospital.
"I was hit helmet-to-helmet from the side of my face and I kind of stumbled over, and after that my ears started ringing and my eyes kind of blacked out a little bit," says Mack Woodfox, a high school player in California. He missed a week of school and a few weeks of practice.
PBS' Frontline aired a special this week, "League of Denial: The NFL's Concussion Crisis." Watch the full program.
Watch the trailer: