The relationship between linear and rotational head accelerations during soccer heading and consequent electrophysiological changes.

In recent years, there has been a growing concern regarding concussive and sub concussive events in sports. In the routine of football, head a ball in different scenarios is common practice, even if now heading is associated with increased risks for brain health. Nowadays, very few studies were conducted on the association between different heading accelerations and subsequent electrophysiological changes of the brain. This study aims to assess whether these changes exists or not, and if there are any differences according to different heading scenarios. The assessment of the brain function is conducted with the Transcranial Magnetic Stimulation, before and immediately after two heading protocols: Passing and Clearing headers. At the same time different methods of head acceleration acquisition are tested. Immediately after both tasks an increase in cortical inhibition period were detected (p-value = 0.04 Passing, p-value = 8.2 * 10^-4 Clearing, α = 0.05). These changes are mainly related to increased rotational acceleration and to their cumulative effect, raising the awareness in headers of this type. Sub-concussive head events, which are not detectable directly through classic assessment methods, are so related to a mild brain injury, with consequent decreased motor activity. These cumulative effects can lead, in future, to increased probability of neurocognitive diseases, and so, will require further investigation.