Concussion (CC) (also called mild head trauma), which accounts for 85% of all head injuries, is very common in professional and amateur athletes. CC is an injury to the brain resulting from the direct or indirect impact of external mechanical forces, momentarily disrupting its function on a cellular level. Unlike more serious head injury (moderate and severe), which can be diagnosed using neuroimaging techniques (CT, MRI, etc.), patients suffering from CC do not necessarily show visible signs of structural abnormalities. As a result, diagnosis of CC is offen difficult.

Recently, several salivary biomarkers (proteins and nucleic acids) of sport related concussion have been identified in professional athletes. However, their reference values have not been determined with sufficient robustness to enable their employment in concussion diagnostic tests.

Concussion (CC) (also called mild head trauma), which accounts for 85% of all head injuries, is very common in professional and amateur athletes. CC is an injury to the brain resulting from the direct or indirect impact of external mechanical forces, momentarily disrupting its function on a cellular level. Unlike more serious head injury (moderate and severe), which can be diagnosed using neuroimaging techniques (CT, MRI, etc.), patients suffering from CC do not necessarily show visible signs of structural abnormalities. As a result, diagnosis of CC is offen difficult. It is essentially based on subjective observational criteria and on the determination of the Glasgow Coma Scale (GCS) score, a score of 13 to 15 indicating potential CC. In approximately 15% of cases, symptoms such as momentary loss of consciousness (less than 30 minutes), amnesia lasting less than 24 hours, neurological deficit, or convulsions can be used to make a diagnosis. In the majority of cases, concussion goes undetected and no specific treatment or rehabilitation is put in place.

Recently, certain molecular biomarkers (BMs) of CC in elite athletes have been identified (Di Pietro et al. 2021; McCrea et al. 2020). However, the reference values of these BMs are not determined with sufficient robustness to enable the best use for concussion diagnostic tests.

To detect these biomarkers, it is first necessary to determine their physiological profiles as well as the changes in intensity associated with intense physical efforts during training session and/or matches.

Inclusion Criteria:

• Male participants aged between 18 and 50 years old.
• Participants willing to comply with the study procedures.
• Participants capable of understanding the purpose, nature, and methodology of the study.
• Participants affiliated to a French social security system or beneficiaries of such a system.
• Participants who have signed the non-opposition form to participate in the research.

Non-inclusion Criteria:

• Participant not affiliated to a French social security system or not a beneficiary of such a system.
• Participants deprived of liberty, protected adults, vulnerable individuals, or minors.
• Participants with a proven or suspected chronic infectious disease that may introduce a risk of contamination during sample handling (laboratories not equipped to handle this type of sample).
• Refusal to sign the non-opposition form to participate in the research.

Non-inclusion specific criteria

• Subject who has had a recent stroke or epilepsy event (within the past two months).
• Subject suffering from neurological diseases.

A total of 80 subjects will be recruited:

• 30 professional sport subject, playing in the professional team of the Montpellier HandBall club (MHB) or the Montpellier Hérault Rugby (MHR) - BRAS S-P.
• 30 leisure sport subjects with moderate physical activity playing in the leisure team of clubs associated with the Montpellier Handball (MHB) or the Rugby Club Méditerranée (RCM) or even to the clubs associated with the Montpellier Handball (MHB) or the Rugby Club Méditerranée (RCM) - BRAS S-L.
• 20 occasional sport subjects with low intensity physical activity and whose weekly sports practice is less than 4 hours, excluding contact sports, recruited at Sys2diag, delegation 13 of CNRS or in sports clubs linked to the study - BRAS S-O.