If you’re a soccer player or the parent of a soccer player, you may want to take note of the latest news in sports medicine: soccer players who repeatedly “head” the ball may be damaging their brains, a recent study shows.

The Albert Einstein College of Medicine in New York studied the brains of 38 amateur soccer players who had all been playing soccer since childhood. Using an advanced imaging technique called diffusion tensor imaging (DTI), an MRI-based technology, scientists examined what happens to human brains when subjected to frequent hits to the head with a soccer ball. “Heading” is a common soccer technique used by players to hit the ball without touching it with their hands.

The study found that soccer players who headed the ball the most frequently suffered brain injury similar to the injuries found in concussion victims, known as mild traumatic brain injury. According to the imaging tests, the areas of the brain that sustained the most trauma were areas responsible for attention, memory, and visual functions. In fact, soccer players who headed the most frequently performed worse on verbal memory and mind-body coordination tests.

The soccer players who exhibited the worst brain damage headed the ball an average of 1,000 to 1,500 times a year or higher. For serious amateur players, this number is not unrealistic, amounting to just a few headers a day. Although the trauma from any individual hit was not enough for brain injury, scientists now believe that the cumulative effect of many hits to the head over time leads to brain damage. The area of the brain that received the most damage was the frontal lobe, just behind the forehead.

Researchers hope that the new data will help soccer programs to refine approaches to training that will minimize the need for heading the ball. While it appears that heading the ball less than 1,000 times a year does not lead to significant injury, experts caution that more research is needed, especially when considering how heading may affect the immature brains of young children. Brain injuries in children may not be immediately apparent, and may instead be attributed to ADHD, learning disabilities, or other problems. Many experts now believe that heading is not appropriate for soccer players under the age of 12.

Until more is known about how often is too often, soccer programs are encouraged to lessen the frequency of heading drills. Parents should also pay extra attention to their child’s complaints of dizziness or headaches during the soccer season.