Heading a soccer ball does carry real risks, particularly with repeated exposure over time. A single header from a typical pass generates around 26 g of force on the head, and while most individual headers fall into the “very low” or “low” brain injury risk category, the cumulative effect of thousands of headers across a career is where the concern grows serious. Former professional soccer players die from neurodegenerative disease at 3.5 times the rate of the general population.
What Happens to Your Brain During a Header
When a soccer ball strikes your forehead, your skull decelerates rapidly while your brain continues moving inside it. Researchers using instrumented mouthguards measured peak forces during headers ranging from about 14 g to 52 g, with the average landing around 26 g. For context, a roller coaster might hit 3 to 5 g, and a concussion-level car crash can exceed 80 to 100 g. Most headers sit well below concussion thresholds individually.
But force alone doesn’t tell the full story. The brain also rotates slightly inside the skull, and this rotational movement creates strain on brain tissue. In a study of 65 headers, all fell into the “very low” or “low” strain categories. However, five headers from the longest pass distances reached a threshold associated with a 25 percent concussion risk. Longer passes and harder-kicked balls produce substantially more force, which is why not all headers are equal.
The Real Concern: Repetitive Sub-Concussive Impacts
The danger of heading isn’t really about one dramatic collision. It’s about what happens when the brain absorbs hundreds or thousands of low-level impacts that never produce obvious concussion symptoms. These are called sub-concussive impacts, and they appear to cause measurable changes in the brain’s wiring.
Brain imaging studies on youth athletes in contact sports have found that a single season of play can alter white matter tracts, the insulated cables that carry signals between brain regions, even when no concussion is ever diagnosed. The more impacts a player accumulated, the greater the changes detected on brain scans. These changes occurred in pathways involved in connecting the front and back of the brain, regions critical for attention, processing speed, and decision-making.
Blood tests tell a similar story. After a session of 40 headers over 20 minutes, collegiate soccer players showed elevated levels of a protein called neurofilament light, a marker released when nerve fibers are damaged. Levels were still elevated a month later. The players also reported symptoms commonly associated with concussion, like headache and dizziness, after the heading session. This suggests that even a single intense heading drill can cause detectable nerve damage and produce concussion-like symptoms, even though no concussion occurred.
Long-Term Risks for Career Players
The most alarming evidence comes from a landmark study published in the New England Journal of Medicine that tracked over 7,600 former Scottish professional soccer players and compared them to 23,000 matched members of the general population. Former players were 3.5 times more likely to die from neurodegenerative disease. The risk varied by condition: Alzheimer’s disease risk was five times higher, motor neuron disease (the condition also known as ALS) was four times higher, and Parkinson’s disease risk was roughly double.
Former players were also prescribed dementia-related medications nearly five times more often than the general population. These are not small differences. While professional players represent an extreme of heading exposure, the dose-response pattern, where more exposure correlates with more damage, raises legitimate questions about recreational and youth players too.
How Many Headers Players Actually Take
Elite male players average about 4.2 headers per match, with some matches requiring as many as 10 to 20 headers for a single player. Defenders head the ball significantly more than any other position, followed by midfielders, then strikers. Over a season of 30 to 50 matches plus training sessions that include heading drills, a defender could easily accumulate several hundred headers per year.
That number compounds over a career spanning 15 or 20 years. A professional defender might head the ball tens of thousands of times before retiring, each impact adding to the cumulative load on the brain.
Why Women Face Greater Risk
Female soccer players experience concussions at higher rates than male players, and several factors contribute to this disparity. Women generally have less neck strength and smaller neck circumference, which means less ability to brace against the force of impact. This translates to greater head acceleration when the ball arrives. Studies also show that women suffer a higher proportion of concussions specifically from ball-to-head contact, as opposed to player-to-player collisions.
There is also preliminary evidence of a hormonal component. Certain phases of the menstrual cycle, particularly when estrogen and progesterone levels drop, may create a window of increased vulnerability to concussion and worse outcomes after one occurs.
Ball Conditions Change the Impact
The soccer ball itself is a modifiable risk factor. A regulation size 5 ball inflated to the maximum allowed pressure (about 16 psi) striking a head at typical match speeds produces roughly 3,600 newtons of peak force. Dropping the inflation to 8 psi, still within legal limits, reduces that force by 20 percent.
Water absorption is another overlooked factor. A soccer ball can gain more than 20 percent of its mass in the first 15 minutes of play on a wet field. FIFA’s rules set no upper limit on ball weight due to water absorption during a match. That extra weight makes each header hit harder. When accounting for water absorption, ball mass becomes the second most important factor affecting impact force, after velocity. Playing with a properly inflated, dry ball is one of the simplest ways to reduce heading risk.
Current Rules for Youth Players
U.S. Soccer banned all heading for players aged 10 and under in 2015. Players aged 11 to 13 are only allowed to head the ball during practice, not in games. England’s Football Association introduced similar guidelines, recommending no heading in training for children under 12 and a graduated introduction for older age groups.
These policies reflect a precautionary approach. Young brains are still developing, skulls are thinner, and neck muscles are weaker, all of which make children more vulnerable to the same forces that adults can better absorb. The age-based restrictions don’t eliminate risk for older players, but they reduce the total lifetime heading exposure, which is the variable most closely linked to long-term harm.
Reducing Risk at Any Level
Proper heading technique matters. Striking the ball with the flat of the forehead, tensing the neck muscles before contact, and actively driving into the ball rather than letting it hit you all reduce the forces transmitted to the brain. Players who head passively, with a relaxed neck, experience greater head acceleration.
Limiting the number of headers in training is another practical step. Many of a player’s lifetime headers happen in practice, not matches, and coaches can design drills that teach positioning and timing without requiring full-force heading repetition. Keeping balls properly inflated (toward the lower end of the legal range) and replacing waterlogged balls during wet conditions are small changes that meaningfully reduce impact forces. Neck strengthening exercises, especially for female players, may also help the head resist acceleration during contact.