Traumatic brain injuries (TBI) in American football have become a national concern. Research has shown that neurocognitive and brain changes can occur from repeated head impacts, even when there is no evidence of concussion. The majority of football players in the U.S. (70 percent) are elementary and middle school students.
In a new study, researchers from Virginia Tech examined exposure to these head impacts in young athletes, aged nine to 12 years, during football games and practice drills.
The aim of the study was to determine under what circumstances high-magnitude head impacts occur and how practice drills compare to actual games with respect to these head impacts. The findings could help coaches and league officials make informed decisions in structuring both practices and games to reduce risks in these young athletes.
The study involved 45 athletes from two youth football teams: Juniors (27 players, mean age 9.9 years) and Seniors (18 players, mean age 11.9 years).
The researchers evaluated biomechanical data and videos during 14 games and 55 practice drills. All of the players wore helmets equipped with accelerometer arrays that measured head impacts in terms of acceleration. Each time a substantial head impact was recorded, data collection was automatically transmitted wirelessly to a sideline computer.
The games and practice activities were recorded to verify the occurrence of a high-magnitude head impact, provide evidence of circumstances surrounding the impact, and record the duration of the activity in which the high-magnitude impact occurred.
The researchers evaluated the impacts based on:
- the position of the team member who received the head impact;
- the place in the field where the impact occurred;
- the cause of the impact, and;
- whether the impact occurred during a game or practice drill.
A total of 7,590 head impacts were recorded by the accelerometer arrays. Of these, 571 (eight percent) were of high magnitude.
Players in “back” positions (quarterback, running back, and linebacker positions) sustained more head impacts than players in other positions. Back position players were more likely to experience high-magnitude head impacts during tackling activities, while players in offensive and defensive line positions were more likely to experience head impacts in blocking activities.
As expected, the more playing time an athlete was given, the greater chance that particular youth would experience a high-magnitude head impact. During games, high-magnitude head impacts occurred more often in the open field — where players in back positions were often found — than in the line of scrimmage.
The researchers also found a higher rate of high-magnitude impacts during games than during practice sessions for both teams. Nevertheless, practice sessions occur more frequently than games, and thus subject players to more opportunities to receive head impacts.
In addition, twice as many high-magnitude head impacts occurred among senior team members than in junior team players. The researchers state that differences in age and weight alone cannot explain this difference. Video data indicates that practice intensity or coaching style may play a role, and this could be a focus of future studies.
“This study builds on a growing body of research on head impact exposure in youth football,” said senior author Steven Rowson, Ph.D.
“These studies are important because they allow you to make data-driven decisions when structuring changes to practice in football to reduce exposure to head impact. Purposeful reduction of exposure means less opportunity for concussion and a reduction in any potential consequences of cumulative exposure.”