Non-invasive Brain Stimulation and Injury Risk Biomechanics

Inclusion Criteria: All participants self-report to be physically active at least 90 minutes per week aged 18-35 years old self-report cleared for sports and physical activity Concussion history group - self-report experiencing a concussion with the National Institute of Health common data element form No concussion history group - self-report not experiencing a concussion with the National Institute of Health common data element form Exclusion Criteria: All Participants self-report attention deficit disorder and/or attention deficit hyperactivity disorder self-report uncorrected vision problems (not included color blindness) self-reported history of neurological disease self-reported history of seizures/syncope or family history of epilepsy self-reported history of frequent severe headaches or migraine. self-reported history of respiratory or heart disease. self-reported structural brain lesions (e.g., stroke) self-reported increased intracranial pressure, such as after infarctions or trauma. self-reported currently using antidepressants, neuroleptic medication, medication that lowers seizure threshold, or any other medication that would interfere with testing. self-reported currently experiencing a high fever (day of testing; >102.9 degrees) self-reported currently undergoing immunosuppressive therapy pregnancy metal anywhere in the head (except the mouth). any electronic implant, such as a cardiac pacemakers, cochlear implant, or deep brain stimulator. any implanted medication pump or intracardiac lines. self-report not being cleared for sport/physical activity by a medical practitioner (i.e., must be cleared by a medical practitioner to participate if the participant had previous traumatic musculoskeletal injury) students working directly in the PI's lab (concussion laboratory, biomechanics laboratory) NCAA athletes Concussion history group - ≥13 symptom severity on the Sport Concussion Assessment Tool (22 total symptoms are graded on a scale of 0-6. Any symptom with a score >0 [1-6], is summed to get symptom severity).