During 30 practices over the course of a recent football season, nine youth players sustained a combined total of 2,125 head impacts while participating in various practice drills, according to a Wake Forest Baptist Medical Center study published this week in the Journal of Neurosurgery: Pediatrics.
The study is among the first of its kind to examine the number, location and magnitude of head impacts that children endure during football practices. Researchers behind the study hope that eventually, after additional studies, they can use their findings to recommend safer youth football practice methods.
“It’s tough to say how far away we are, but I think that this study is really a step toward that,” said Jillian Urban, an assistant professor of biomedical engineering at Wake Forest Baptist and the lead investigator of the study. “We can start to have conversations … in the football community and say what does this mean, and how can we use this information to inform what you’re doing on-field?”
Emerging science in recent years has increased awareness of the risks of playing football, and the long-term consequences of concussions, in particular, have become part of the national dialogue surrounding the sport. The Wake Forest Baptist study didn’t draw conclusions about the effects of head impacts, but it showed how often they occur during routine youth football practice drills.
Urban said she focused on practices, and not games, because she concluded in previous research that about two-thirds of the head impacts a youth football player endures occur in practice. She and her research team generated their data by following nine players on a Winston-Salem youth football team.
The players, whose average age was 11, wore helmets with sensors that measured head acceleration. The sensors recorded data during preseason, regular-season and postseason practices, and the researchers also recorded video and matched the head impacts to the drills in which they happened.
The football team used 11 types of drills during its 30 practices, though not every practice included every drill. Researchers found that the majority of head impacts occurred during drills involving several players.
Some of the highest-magnitude head impacts, however, happened during the open-field tackling drill, which the team used in five of its 30 practices. Researchers suggested that drill resulted in high-magnitude impacts because of the speed players built up before colliding with one another.
In the study, a high-magnitude head impact was considered to be one that measured at least 60g, which is a measure of acceleration and force. The sensors recorded impact data if the impact was greater than 10g, which is considered a normal impact.
Urban, the lead investigator, said it would be difficult to provide a real-world example of how a person could sustain a 10g or 60g head impact off a football field.
“It’s hard to draw a comparison to something that someone would resonate with that wouldn’t be too alarming,” she said. “But for comparison, we normally see that 50 percent of our impacts are between the 10 and 20g range and that’s just our regular just basic contact that you see pretty much on any drill.”
The data Urban and her colleagues collected showed not only the force of head impacts, but also their point of origin. Researchers found that the most common impact location, overall, was at the front of the helmet, but they also discovered that during high-magnitude collisions, the most common impact location was at the top of the helmet. That finding could indicate improper tackling technique.
The authors of the study, titled “Head impact exposure measured in a single youth football team during practice drills,” acknowledge that it is small. Urban said additional research is needed to form recommendations about how to make youth football practices safer.
The link between head impacts sustained at a young age and any potential health problems is also unclear. This study, though, represents a start, and it comes at a time when the risks of playing football are becoming more clear.
“For several years we’ve been studying head impact exposure in high school and collegiate populations,” Urban said, “but only in the last five years have we started really understanding what’s going on in the younger athletes.”