To compare the serum levels of S100B after head trauma with the effect of heading, high-intensity exercise, and playing in a league match. Heading and head trauma in soccer have been suspected to cause brain impairment. The protein S100B is a marker of acute neuronal tissue damage.METHODS
Baseline S100B was measured in 535 Norwegian professional soccer players. Two hundred twenty-eight head impacts were registered from 352 league matches. Three teams (n = 48) performed a high-intensity exercise session without heading and a low-intensity session with heading exercises. A blood sample was drawn from each participant within 1 hour (B1) after the session, and another sample (B12) was drawn after a match or training session. The players were assigned to four groups: Head Impact (n = 65), Match Control (match participants without head impact, n = 49), High-intensity Exercise (n = 35), and Heading (n = 36).RESULTS
Serum S100B increased from baseline to B1 for all groups. The increase for the match groups (Head Impact and Match Control) was significantly higher than for both training groups. However, no significant differences between the Head Impact and Match Control groups or between the two training groups were found. A total of 39 players (33.9%) had elevated B1 values (≥0.12 ng/ml) after a match, but these findings were equally distributed between the Match Control and Head Impact groups.CONCLUSION
Both soccer training and soccer matches cause a transient increase in S100B. There is a possible additive effect of activity with high intensity and heading, but minor head impacts do not seem to cause an additional increase.