The investigators will test the central hypotheses according to the following Specific Aims:

Aim 1. Determine if an individually prescribed exercise program initiated within the first week of mild traumatic brain injury can reduce the risk of developing persistent post-concussion symptoms relative to usual care. The investigators hypothesize that the exercise group will have a lower risk of developing persistent post-concussion symptoms than the usual care group.

Aim 2. Examine the effect of a two-month exercise program on psycho-social, pain interference, and sleep outcomes following mild traumatic brain injury. The investigators hypothesize the exercise group will report lower anxiety, depression, and pain interference ratings, and higher peer relationship and sleep quality ratings two months of exercise following mild traumatic brain injury compared to usual care.

The long-term research goal of the proposed study is to develop individualized sub-symptom exercise prescriptions for youth who sustain mild traumatic brain injury that can help to alleviate mild traumatic brain injury symptoms, reduce the risk of persistent post-concussion symptoms, and improve psychosocial outcomes. The overall objectives of this application are to prospectively (1) determine if a prescribed exercise program initiated within the first week of mild traumatic brain injury can reduce the risk of developing persistent post-concussion symptoms and (2) examine the effects of an exercise program on psychosocial, sleep, and pain outcomes when initiated within 7 days of injury and continued for two months. The investigators will address these objectives by testing the central hypotheses that those assigned to an exercise intervention will have lower risk of developing persistent post-concussion symptoms and will report lower anxiety, depression, and pain interference ratings, higher peer relationship ratings, and better sleep quality ratings compared to usual care. In order to achieve this, the investigators will use a block stratified randomized intervention design. Block stratified randomization procedures will be conducted according to standard procedures so that sample numbers are equally assigned to each group, selected due to the relatively small sample size of the proposed study. Participants will be identified, enrolled, and assessed within 5 days of mild traumatic brain injury, randomized to an exercise intervention or usual care group 3-7 days after mild traumatic brain injury, and follow-up with in person assessments at approximately one and two months post-injury.

Inclusion Criteria:

1. Concussion or mTBI diagnosis by a board-certified Sports Medicine physician, pediatric Emergency Medicine physician, general pediatrician physician, or advanced practice provider under the direction of a physician. This will be defined in a similar manner according to available guidelines: a direct or indirect blow to the head, face, neck, or elsewhere that manifests with the presence of symptoms and neurological impairment
2. Aged 10 - 18 years to ensure a pediatric sample of participants.
3. A persistent postconcussion symptom risk score ≥ 9 to ensure all participants are in the high risk of persistent postconcussion symptom category.
4. A Post-Concussion Symptom Inventory score > 9 to ensure participants have not recovered by the time they enroll in the study.
5. Access to an internet connection (via computer or smart phone) so that physical activity and exercise can be tracked via heart rate monitor.

Exclusion Criteria:

1. Concurrent lower extremity injury so that exercise testing results are not confounded by other injury.
2. Aerobic exercise contraindication so that participants are able to complete the exercise testing protocol.
3. Diagnosed mild traumatic brain injury by a healthcare provider within 6 months of qualifying injury to ensure that residual effects of prior mild traumatic brain injury do not bias the results of our investigation.
4. Mild traumatic brain injury that results in positive findings on neuroimaging, or extra-axial or intraparenchymal bleeds to avoid potential injuries that are more severe than mild traumatic brain injury.