OBJECTIVE To evaluate the effect of soccer heading on intracranial pressure (ICP) in trained athletes. METHODS Eight subjects (all male, 21.7±1.7 years) were recruited from the UC San Diego soccer team. ICP and cardiovascular variables were recorded before and after 6 repeats of heading a soccer ball kicked from 35 yards away, into a goal. ICP was estimated non‐invasively from acoustical evoked tympanic membrane displacement (Vm), where a more negative volume displacement is correlated with higher ICP. Mean arterial pressure (MAP), heart rate (HR; Nexfin, Netherlands), and ICP were recorded in three different postures, 15° head up tilt (HUT), 0° supine, −15° head down tilt (HDT), in a randomized order. RESULTS Mean Vm at 15° HUT was 37.81±133.21 nL at baseline and −20.82±158.27 nL immediately post soccer heading (P=0.0482, paired t test), analogous to an increased ICP. At 0° supine, mean Vm was −46.19±178.50 nL at baseline and −84.27±183.55 nL after impact (P=0.0321, paired t test). At −15° HDT, mean Vm was −148.48±196.07 nL at baseline and −187.02±186.19 nL immediately post soccer heading (P=0.1176, paired t test). MAP and HR did not significantly change between the baseline and post soccer heading measurements. DISCUSSION After repeated soccer ball heading, ICP significantly increased at 15° HUT and 0° supine, while ICP at −15° HDT, MAP and HR did not significantly change. The relative increase in ICP associated with HDT is comparable to previously described trends. Although the measurement technique currently employed does not provide an absolute ICP baseline, the technique has been established as useful in evaluating relative changes. Under that interpretation, these results reflect what may be an elevated ICP related to soccer heading impacts. Accordingly, the results of this study suggest a potential health risk of participation in head contact sports. Support or Funding Information NASA (80NSSC19K0020) and Novo Nordic Foundation (NNF16OC0019196) Soccer Heading Increases Intracranial Pressure at Head Up Tilt and Supine Positions Volume displacement of tympanic membrane (Vm), measured non‐invasively from acoustical evoked tympanic membrane displacement, indicated an increase in intracranial pressure (ICP) after soccer heading at 15° head up tilt (HUT) and 0° supine (n = 8, paired t test, *P < 0.05). No significant increase in ICP at −15° head down tilt (HDT) was observed after soccer heading.

Objective To evaluate whether intracranial pressure (ICP) continued to stay elevated in trained athletes 24 hours after soccer heading. Methods Eight male subjects (21.7±1.7 years) were recruited from the UCSD soccer team to participate in the study. Baseline ICP and cardiovascular variables were recorded, and measurements were repeated after subjects underwent the heading trial. Acoustical evoked tympanic membrane displacement was used to estimate ICP, where decreasing volume displacement (‐Vm) is associated with an increase in ICP. Mean arterial pressure (MAP) and heart rate (HR) were measured through the volume‐clamp method. The heading trial consisted of 6 repeated headers of a soccer ball kicked from 32 meters away into a regulation goal. Follow up measurements of ICP, MAP, and HR were recorded 24 hours after heading trial. Measurements were taken in three randomized positions: 15° head‐up tilt (HUT), 0° supine, ‐15° head‐down tilt (HDT). Results At 15° HUT, baseline mean Vm was 37.81±133.21 nL, ‐20.82±158.27 nL immediately after heading trial (P=0.0482, paired t test), and 27.20±140.61 nL at 24 hours post soccer heading (P=0.1738, paired t test), corresponding to a significant increase in ICP immediately after the heading trial that then returns to baseline levels after 24 hours. At 0° supine, baseline mean Vm was ‐46.19±178.50 nL, ‐84.27±183.55 nL after heading trial (P=0.0321, paired t test) and ‐62.90±135.44 nL at 24 hours post soccer heading (P=0.5048, paired t test), corresponding to the same trend observed in the 15° HUT position. At ‐15° HDT, mean Vm was ‐148.48±196.07 nL at baseline, ‐187.02±186.19 nL after heading trial (P=0.1176, paired t test), and ‐151.10±174.86 nL at 24 hours post soccer heading (P=0.9329), corresponding to no significant increase in ICP at either time point. MAP and HR did not significantly change at any point after soccer heading. Discussions ICP significantly increased after soccer heading at 15° HUT and 0° supine but returned to baseline levels after 24 hours. ICP at ‐15° HDT, MAP, and HR did not significantly change immediately after soccer heading or 24 hours after soccer heading. While these results demonstrate a mild increase in ICP that subsides after 24 hours, athletes may experience these transient increases in ICP continuously for extended periods of time during their entire athletic careers. These cycles of increased ICP may result in a state of intermittent but persistently altered cerebral blood flow, which may suggest a health risk of participating in head contact sports such as soccer.