Controlled DTI Evaluations in High School Football and Female Soccer to Evaluate Efficacy of Jugular Compression Collar

The purpose of the study is to monitor longitudinal changes in brain structure between the preseason and postseason, in a population of football and soccer playing athletes wearing the Device and compared to a similar population not wearing the device. Secondly, the purpose is to determine the efficacy of device to reduce alterations in brain structure relative to amount and magnitude of sustained head impacts. Finally, to show that DTI efficacy and safety results can be prospectively confirmed in a multi-school investigation. Test the null hypotheses of no difference between collar users and non-collar users changes from baseline to end of season for: * Primary: Alterations in pre-defined DTI metrics (AD, MD, RD) are significantly reduced in the neck collar group at EOS relative to BL. * Secondary: Alterations in pre-defined DTI metrics is explained by the number of hits, the hit intensity, and the intensity per head impact over the season non-collar users. In addition, secondary analytics on data derived from injury surveillance (musculoskeletal, concussion and symptom/severity scores), behavioral (Trail Making, Postural Sway, Flanker, Task-switching, Near Point Convergence, ADHD and King Devick) or imaging (DTI, fMRI, T1, T2, and MRS) will be evaluated.