Up to 22 per cent of football injuries are concussions that can result from players using their heads to direct the ball during a game.
To reduce risk of injury, a new study recommends preventing how hard a ball hits the head by inflating balls to lower pressures and subbing them out when they get wet.
The study, conducted by Purdue University engineers, found that inflating balls to pressures on the lower end of ranges enforced by football governing bodies such as the NCAA and FIFA could reduce forces associated with potential head injury by about 20 per cent.
But if the ball gets too wet, it can quickly surpass the NCAA weight limit for game play and still produce a nasty impact, the researchers said.
“If the ball has too high of a pressure, gets too waterlogged, or both, it actually turns into a weapon. Heading that ball is like heading a brick,” said Eric Nauman, a Purdue professor of mechanical engineering and basic medical sciences with a courtesy appointment in biomedical engineering.
Football governing bodies already regulate ball pressure, size, mass and water absorption at the start of a game, but Nauman’s lab is the first to conduct a study evaluating the effects of each of these ball parameters on producing an impact associated with potential neurophysiological changes.
The results are published in the journal PLOS One. The researchers discuss the work in a video on YouTube at https://youtu.be/3b_19wW7K6A.
The study also evaluated ball velocity, finding that this variable actually contributes the most to how hard a ball hits. But ball pressure and water absorption would be more realistic to control.
“You can’t control how hard a player kicks a ball. There are other ways to decrease those forces and still have a playable game,” Nauman said.
A professional football player heads the ball about 12 times over the course of a single game and 800 times in games over an entire season, past studies have shown.
The lower end of NCAA and FIFA pressure ranges, which the researchers discovered could help reduce the ball’s peak impact force, already aligns with pressures specified by the manufacturer on the ball. These specifications would provide an easy way to know if a pressure is low enough to reduce risk of head injury.
“The study really sheds light on the issue of how the weight and impact of the ball can change under different conditions. Sports governing bodies and manufacturers can use this research to further reduce the risk of lasting brain functional or structural injury as a result of head impacts accrued through soccer game play,” said Francis Shen, a professor of law at the University of Minnesota whose research focuses on the intersection of sports concussions and the legal system.
Nauman and Shen met through the Big Ten-Ivy League Traumatic Brain Injury Collaboration, a multi-institutional research effort to better understand the causes and effects of sport-related concussion and head injuries.
In this study, Nauman’s lab tested three football ball sizes – a 4, 4.5 and a 5 – by kicking them against a force plate in a lab. Even though only size 5 balls are played by professional adults, the researchers also observed the smaller 4 and 4.5 sizes played by children under the age of 12 to evaluate how m