A new study from the Royal Dutch Football Association finds that heading the ball during amateur soccer matches is linked to short-term increases in blood biomarkers associated with neural damage. Researchers report a dose-dependent response: the more headers a player takes, the greater the rise in two key proteins - S100B and phosphorylated tau 217.
The study followed 302 adult male amateur players across 11 matches from August to December 2024. Video analysis tracked heading frequency and intensity, while blood samples were taken before matches, immediately after, and again 24 to 48 hours later.
Players who headed the ball showed significant post-match increases in S100B. High-impact headers - those with trajectories over 20 meters - were linked to even larger increases in both S100B and phosphorylated tau 217. The biomarker elevations returned to normal within 24 to 48 hours.
The findings add to growing concerns about repeated head impacts in soccer, even at non-professional levels. The authors call for further longitudinal studies to understand whether these temporary changes contribute to long-term neurological risk.