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

" Brain Changes After Repetitive Head Impacts in Soccer and the Effects of a Protective Device: Biomechanical, Cognitive, Electrophysiological and Multimodal Neuroimaging Study "

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

Electrophysiological recording of Motor Evoked Potentials consisting of the application of transcranial magnetic stimulations (TMS) and the collection of muscle activity by electromyogram (EMG)

Corticomotor inhibition measured in milliseconds using transcranial magnetic stimulation and electromyographic recordings.

Corticomotor inhibition measured in milliseconds using transcranial magnetic stimulation and electromyographic recordings.

Mean strength ratio between flexor and extensor muscles of the neck measured in Newton using a dynamometer

Mean strength ratio between flexor and extensor muscles of the neck measured in Newton using a dynamometer

Inclusion Criteria: Male 18 to 25 years, enrolled in French Social Security, recruited from the soccer teams of the University of Bordeaux Exclusion Criteria: Abnormal neurological examination Taking drugs targeting the central nervous system Any unhealed injury History of head trauma, or other notion of central nervous system injury History of severe high blood pressure, diabetes, chronic cardiovascular pathology, progressive or debilitating disease Family history of epilepsy Contraindication to MRI: head circumference> 60 - Claustrophobia - Pacemaker, Implantable Neurostimulation, Implantable Defibrillator - Cochlear Implants - Ocular or cerebral ferromagnetic foreign body - refusal to be informed of an anomaly detected with MRI Individuals under legal protection or unable of giving their informed consent