Since the Michigan High School Athletic Association implemented restrictions on the number of full-contact football practices that middle schools and high schools are allowed to conduct per week, head impacts have plunged by nearly 42 percent, according to a study recently published in the Journal of Athletic Training.
Prior to 2014, the state association had no limit on the number of full-contact football practices allowed per week. In March 2014, it adopted a new policy that prohibited teams from conducting more than one full-contact practice per day prior to the beginning of the regular season and no more than two per week once the regular season commences.
For this study, authors from the NeuroTrauma Research Lab in the School of Kinesiology at University of Michigan examined 41 football players from a single school who were each equipped with special helmets that recorded data regarding head impacts. They found that from 2013 to 2014, head impacts decreased by an average of 41.8 percent across all players involved in the study, which largely stemmed from a 52.9 percent drop in head impacts during practice sessions.
In 2013, players at all positions averaged 359 head impacts in practices, whereas in 2014, the number plummeted to 169. Overall, head impacts plunged from 9,335 during practices in 2013 to 4,062 during practices in 2014. Across practices and games, the average number of head impacts dropped from 592 per athlete to 345.
Linemen experienced the biggest decline in head impacts at practices, seeing a 45.8 percent drop from 2013 to 2014. Receivers, cornerbacks, and safeties all experienced 40.8 percent fewer head impacts between those two seasons, while tight ends, running backs, and linebackers had a 39.0 percent decline. Quarterbacks were the only position to exhibit no statistically significant decrease in head impacts from 2013 to 2014 in practices, presumably because they’re subjected to fewer hits during practice than players at all other positions. No position group had a significant decline in head impacts during games over that span.
“The study results reinforce the impact that rules changes can have on the players,” said the study’s lead author Steven Broglio, the director of the University of Michigan’s NeuroTrauma Research Lab, in a statement. “How this reduction influences concussion risk and long-term cognitive health remains unknown.”
The change in practice rules did not lead to a significant change in the magnitude of head impacts, although impact rates to the front, back, and side of the head all significantly declined between 2013 and 2014. According to the findings, linemen experienced a nearly 39 percent decline in front-helmet impacts.
Since the coaching staff and offensive scheme at the school “remained consistent” across both seasons, the study authors hypothesized that the contact limitations in practices “may have been the cause of this decrease,” although they stressed the need for further research on that front. If their findings can be replicated across youth-football leagues, states currently without some sort of restriction on the number of full-contact practices allowed per week would likely be pressured to follow suit.
A version of this news article first appeared in the Schooled in Sports blog.