“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.
The Purdue study (published in the journal PLOS One) cites other research on the frequency of concussions caused by heading the ball and "found that inflating balls to pressures on the lower end of ranges enforced by soccer governing bodies such as the NCAA and FIFA could reduce forces associated with potential head injury by about 20%."
FIFA rules stipulate a soccer ball's weight must be not less than 14 ounces and no more than 16 ounces. The Purdue study suggests that balls getting wet can quickly surpass the weight limit -- and increase head injury risk. While ball velocity "contributes the most to how hard a ball hits," ball pressure and water absorption are easier control.
The research included tests with balls sizes 4, 4.5 and 5.
"This was a very simple experiment," Nauman said. "But there just hasn’t been much data out there on these issues, and that’s a huge problem.” The next step would an experiment replication outside of the lab.
The study focused on PSI within FIFA's regulations, but one wonders how frequently youth soccer is played with balls inflated over the maximum.
Have you ever seen a youth referee measure the balls' PSI?
Yes, I have seen youth referee's check and adjust ball pressure.
Yes, I have always considered it a safety factor that can be controlled.
Anyone who played back in the era of leather balls understands what a difference weight makes.
Anyone who wears contacts understands what heading safe balls does to the brain judging by what happens to the eyes on impact.
I firmly believe that heading should stay a part of the game, but we should teach tactical alternatives to avoid heavy impacts to the head. For instance glancing headers or first touch with chest instead of head. The risk of head to head contact can be reduced by pointing a shoulder at the opponent and jumping straight up.
Agree Bob. Those cold, heavy balls were a real incentive for the adage of "you strike the ball first, not be stricken by it." I'm also trying to reconcile the days of my youth starting with leather balls and now starting to wear them. Better have a sense of humor during the aging process.
heading should not be used by someone under the age of 15. at the same time proper heading techniques should be taught. I've seen too many young players spearing the ball with the top of their head instead of their forward.
I agree with the previous commenter that teach players to use their chest to gain control of the ball
Thanks Mike for looking into this subject. The older leather balls got heavy when wet but were also lighter than the modern synthetic balls when not wet. This was just one of the findings revealed back in 2017 in Alan Shearer's Demential, Football and Me Documentary (https://youtu.be/vMoDtIJ_b8I). Many if not almost all of these new balls even when suppossedly properly inflated feel like rocks. No wonder why so many players oftn cringe after they head what seems like a normal heading opportunity. With the NCAA required Wilson match balls, I contacted Wilson and they said the ball should be inflated to 10.5psi which is an absolute rock. Our men's team who like the balls filled a bit more hard stop at 9psi with our women's team holding at 8.5psi. We really need someone to look into these ranges and recommendations.
When I refereed pro games, we had to make sure all the balls were inflated to the maximum, or the players complained. As a player, I didn't like them quite that hard.
As for water-logged leather balls, when I first started playing (in the 1970s) I can still remember heading a punt with a water-logged leather ball. It almost knocked me out...
If a player is taught to head properly while also being taught how to avoid potential collisions at an early enough age, there should not be a problem. The problem becomes when you don't teach someone to head a ball in a competitive situation until they're 15 because they have no spatial awareness and focusing only on the ball rather than on the entire picture. These players are dangerous to everybody else. This is no different than learning how to catch a baseball at age 15 when they should be doing at the earliest age possible so it becomes second nature. If you're letting players spear the ball - that's a coaching problem.
Tony, my belief is that heading, such as repetitive heading during training, is an avoidable risk and unnecessary. Impacts to the head shake the brain and can cause long term problems even when there is no symptom of a concussion.
I see nothing wrong with juggling as that is practicing soft touch or teaching technique which requires hard impact and only a few repetitions.