The specific objectives are to: (1) adapt the MBY intervention protocol to suit the unique needs of youth with mTBI (i.e. safety, fatigue), (2) collect data on the impact of MBY on HRV, self-efficacy and participation, (3) describe changes in HRV, self-efficacy and participation associated with MBY across pre-intervention, post-intervention and 3 months following intervention, (4) identify if post concussion symptoms change (i.e. increase or decrease) following MBY and (5) identify if changes in post concussion symptoms occur with changes in HRV, self-efficacy and participation.