" Acute Brain Changes After Repetitive Headers in Soccer and the Effects of a Protective Device "

Soccer, the most popular sport in the world, exposes players to repeated head impacts and concussions, due to contact with another player or with the ground. Moreover, routine game-play in soccer involves intentional and repeated head impacts through ball "heading", with frequent high velocities, which might cause a transient brain dysfunction. In this pre-post prospective interventional study, 22 soccer players will perform 10 headers from machine-projected soccer balls at standardized speeds, modelling routine soccer practice. They will perform heading series in 2 different oral conditions, on different days at least 1 week apart: 1) Without mouthguard and tight jaws ; 2) With mouthguard and tight jaws. The strength of the neck muscles will be measured before the heading series. The kinematic of the movement will be recorded during each impact during the 2 heading series, as well as the activity of the jaw muscles which will be recorded by electromyogram. Before and after each heading series, electrophysiological data, multimodal magnetic resonance imaging (MRI), and cognitive computerized assessment will be acquired