How do the Neck Muscles Influence Head Acceleration During Sport-associated Impact Events in High School Athletes?

Inclusion Criteria: * Provision of signed and dated informed consent form, or assent form with parental consent for minors * Stated willingness to comply with all study procedures and availability for the duration of the study * Participated in a soccer team, club, or other soccer program/organization within the preceding 2 years * Be willing to adhere to the assigned exercise regimen Exclusion Criteria: * Prior history of trauma-induced neck injury of sufficient severity to require treatment by a medical provider within 30 days of injury or to limit sport participation for \> 1 day (note: having received routine chiropractic treatment in the absence of a recent traumatic injury to the neck will not be considered to meet this criterion) * Any prior history of whiplash injury, stinger/burner, or cervical radiculopathy diagnosed by a medical provider * Any prior history of bone, disk, neural, or ligamentous abnormality identified on cervical spine medical imaging performed for any reason that is felt by the PI (or designee) to present a risk to study participation * Any prior history of surgery involving the cervical spine (note: having undergone non-spine surgery to the soft tissue structures in the neck will not necessarily exclude participation, but will be considered on a case-by-case basis by the PI, or his designee, with consultation from the performing surgeon when deemed appropriate) * Self-report of moderate or severe neck pain (rated as 5 or greater on a 10-point pain scale) lasting \> 1 day in the previous 6 months that required any evaluation or treatment by a medical provider or that limited sport participation for \> 1 day (note: having received routine chiropractic treatment in the absence of moderate-severe neck pain will not be considered to meet this criterion) * Self-report of low back pain (any severity) associated with morning stiffness occurring 30 days or more in the previous 3 months. * Prior episode(s) of unexplained upper extremity numbness, tingling, or weakness suspicious to the PI, or designee, for a stinger/burner or cervical radiculopathy in the last 3 years * Prior history of concussion in the previous 6 months diagnosed by a medical provider or suspected by the subject, or the parent/guardian of a minor (if no medical evaluation was sought), or any diagnosed/suspected concussion without full recovery and clearance to resume unrestricted sport participation. * Personal history of migraine headaches within the previous 3 years diagnosed by a medical provider, with one or more headache episodes, or requiring treatment. * Personal history of anxiety disorder diagnosed by a medical provider that has either been difficult to control, affected daily function, or required treatment with medication or counseling within the previous 3 years. * Parental/guardian known history of anxiety disorder diagnosed by a medical provider that has either been difficult to control, affected daily function, or required treatment with medication or counseling within the previous 3 years. * Prior personal of any of the following or known family history of the following medical conditions known to be associated with atlanto-axial instability diagnosed by a medical provider: parental history of Down Syndrome, Ehlers-Danlos Syndrome, or Marfan syndrome; parental, or sibling history of rheumatoid arthritis/other systemic inflammatory disease with joint involvement or mucopolysaccharidosis * Known exposure to or infection with head lice in the previous 30 days * Known or suspected pregnancy (for females) * Serious allergic reaction to nickel/metal jewelry * Any contraindication to MRI scanning * Presence of significant abnormality on a standardized screening neurological and musculoskeletal physical examination * Prior participation in a resistance exercise training program including exercises specifically intended to target the neck muscles within 3 months of enrollment, or intention to begin participating in such an exercise program outside of the study protocol during the upcoming 12-week study period * Unable to speak and understand English