Crunch!

A huge hammer swings down from the ceiling and slams into a plastic football helmet with a loud THONK! The force of the blow sends its wearer wobbling backward. But don’t worry! The helmet isn’t fitted on a person—it’s fitted on a dummy head. This fake head is one of many at the Virginia Tech Helmet Lab, which evaluates the safety of football helmets for youth, high school, and college players.

The swinging hammer replicates the shockingly hard blows football players experience on the field. It allows engineers like Steve Rowson, the director of the lab, to determine whether a helmet is actually doing its job. “We can’t bring people into the lab, hit them, and see if they get hurt,” says Rowson. “This is an indirect way of measuring injury.”

After collecting measurements, engineers at the Helmet Lab calculate the odds that a player might get a concussion if hit while wearing a specific helmet. A concussion is a brain injury caused by a blow to the head (see “What Causes A Concussion”). Each helmet is ranked on a scale of one to five stars. Five-star helmets have the lowest risk for a concussion.

The Virginia Tech Helmet Lab started publishing its ratings online about 15 years ago. This decision changed the football helmet industry forever. Before ratings were shared with the public, helmet design hadn’t changed much from the hard plastic shells that first became popular in the 1970s (see “Helmet Evolution”). But afterward, companies all wanted to create products with five-star ratings. Engineers, scientists, and sports organizations started working together to create head gear that better protects players.

A huge hammer swings down from the ceiling. It slams into a plastic football helmet. THONK! The helmet’s wearer wobbles backward from the force of the blow. But don’t worry! The helmet isn’t on a person. It’s fitted on a dummy head. This fake head is one of many at the Virginia Tech Helmet Lab. The lab rates the safety of football helmets for youth, high school, and college players.

Football players experience shockingly hard blows on the field. The swinging hammer reproduces this. It allows engineers to determine whether a helmet is doing its job. Engineer Steve Rowson is the lab’s director. “We can’t bring people into the lab, hit them, and see if they get hurt,” says Rowson. “This is an indirect way of measuring injury.”

What would happen if a player got hit while wearing a certain helmet? Engineers at the Helmet Lab collect measurements. Then they calculate the odds that the player might get a concussion. That’s a brain injury caused by a blow to the head (see “What Causes a Concussion”). Each helmet is ranked on a scale of one to five stars. Five-star helmets have the lowest risk for a concussion.

The Virginia Tech Helmet Lab publishes its ratings online. They started doing that about 15 years ago, and it changed the football helmet industry forever. Helmets of hard plastic shells had become popular in the 1970s. The design didn’t change much, until the lab shared ratings with the public (see “Helmet Evolution”). After that, companies all wanted to create products with five-star ratings. Engineers, scientists, and sports organizations started working together. They aimed to create head gear that protects players better.

Football is America’s most-watched sport—and also one of its most dangerous. In addition to obvious injuries like strained muscles and bruises, there are about 200 recorded concussions per season in the National Football League (NFL). In 2018, the U.S. Centers for Disease Control and Prevention found that, of all youth sports, boys’ tackle football has the highest rate of concussions. And once you get one concussion, you’re more likely to get another.

When football players slam into each other, the impact generates an incredible amount of force. Newton’s Second Law of Motion states that an object’s force depends on its mass and acceleration. So two big football players running at top speed can hit each other with up to 6,700 Newtons (1,500 pounds) of force. That’s like having a cow drop down on top of you! Helmets are the only line of defense between these tooth-rattling impacts and brain-shaking head injuries. 

Football is America’s most-watched sport. It’s also one of its most dangerous. Some injuries are obvious, like strained muscles and bruises. Besides that, about 200 concussions are recorded per season in the National Football League (NFL). In 2018, the U.S. Centers for Disease Control and Prevention studied youth sports. They found that boys’ tackle football has the highest rate of concussions. And if you get one concussion, you’re more likely to get another.

Football players often slam into each other. This impact produces an incredible amount of force. An object’s force depends on its mass and acceleration. That’s Newton’s Second Law of Motion. If two big football players run at top speed, they can hit each other with up to 6,700 Newtons (1,500 pounds) of force. That’s like having a cow drop on top of you! These tooth-rattling impacts can cause brain-shaking head injuries. Helmets are the only line of defense.

According to Rowson, the best helmets are the ones that can deform, or change shape, when hit. Deforming stretches out the duration of the impact, which reduces the forces the player experiences. “In car crashes, an airbag turns a two-millisecond impact into a 40-millisecond impact,” says Rowson. “That dramatically decreases injury risk. So when we think about a football helmet, we want to extend the impact duration as much as possible.” 

In the past decade, helmets have become thicker, softer, and more flexible. Some are lined with bendy 3-D-printed plastic. Others have cutouts that allow certain areas to flex more when hit. But if a helmet gets too big and heavy, players won’t wear it, says Rowson. “People don’t want to look like bobbleheads,” he says. “But the more material you have, the safer you are.” 

Scientists have also discovered that helmets are not one-size-fits-all. “Twenty years ago, if I showed you a varsity helmet and a youth helmet, you wouldn’t be able to tell the difference,” says Rowson. “We’ve found that younger players hit their heads differently than older players do.” Because of this, the Helmet Lab tests youth helmets differently, which led to the creation of helmets designed specifically for kids.

Rowson says the best helmets are the ones that can deform. They change shape when hit. Deforming stretches out the duration of the impact. That reduces the forces on the player. “In car crashes, an airbag turns a two-millisecond impact into a 40-millisecond impact,” says Rowson. “That dramatically decreases injury risk. So when we think about a football helmet, we want to extend the impact duration as much as possible.” 

Helmets have changed in the past decade. They’re thicker, softer, and more flexible. Some are lined with bendy 3-D-printed plastic. Others have cutouts. That allows certain areas to flex more when hit. But if a helmet gets too big and heavy, players won’t wear it, says Rowson. “People don’t want to look like bobbleheads,” he says. “But the more material you have, the safer you are.” 

Scientists have also found that helmets are not one-size-fits-all. “Twenty years ago, if I showed you a varsity helmet and a youth helmet, you wouldn’t be able to tell the difference,” says Rowson. “We’ve found that younger players hit their heads differently than older players do.” So the Helmet Lab tests youth helmets differently. That led to helmets that are specially designed for kids.

Even with new-and-improved helmets, full-contact sports like football still carry risks. “We are not going to engineer our way out of this problem,” says Steven Broglio, a neuroscientist at the University of Michigan who studies head injuries in sports. Broglio and Rowson both agree that the way we play football and respond to injuries needs to change too. In recent years, the NFL has adjusted some of its rules to try to make the game safer, like penalizing players who use their heads as battering rams and instituting new medical protocols for treating concussions. The league has also banned helmets that perform poorly in safety tests.

Things can also get safer behind the scenes. For example, in 2019, a Michigan high school association reduced the number of full-contact practices for high school teams down to two days a week. In only a year, head impact exposure dropped by about a third. An even safer option, says Broglio, is for young players to avoid playing tackle football. A growing number of people are choosing flag football—where you pull a flag from another player’s belt instead of tackling them. This low-contact version of the sport leads to 94 percent fewer head impacts during practices and games.

Today’s football helmets are far more effective than those of the past. But even with upgraded technology, it’s still important for players to be careful.  “You can have padding—and engineers can work as much as they want to make that padding better—but it doesn’t make you invincible,” says Broglio.

We may have new-and-improved helmets. But full-contact sports like football still carry risks. “We are not going to engineer our way out of this problem,” says Steven Broglio, a neuroscientist at the University of Michigan. He studies head injuries in sports. Broglio and Rowson both agree that the way we play football also needs to change. So does the way we treat injuries. In recent years, the NFL has adjusted some rules to make the game safer. For example, players are penalized for using their heads as battering rams. New procedures are in place for treating concussions. The league has also banned helmets that perform poorly in safety tests.

Things can also get safer behind the scenes. For example, a Michigan high school association made a change in 2019. It reduced the number of full-contact practices for high school teams to two days a week. In only a year, head impact exposure dropped by about a third. An even safer choice is for young players to avoid playing tackle football, says Broglio. More people are choosing flag football. In this low-contact version of the sport, you pull a flag from another player’s belt instead of tackling them. This leads to 94 percent fewer head impacts during practices and games.

Today’s football helmets are far more effective than older ones. But upgraded technology isn’t enough. Players still need to be careful. “You can have padding—and engineers can work as much as they want to make that padding better—but it doesn’t make you invincible,” says Broglio.