*2.1. Participants*

Five healthy young adults (3 females, mean (SD), age = 24.0 (2.3) years, height = 1.77 (0.12) m, mass = 77.4 (16.4) kg) and 5 individuals with mTBI (3 females, age = 36.4 (11.8) years, height = 1.74 (0.07) m, mass = 72.7 (11.2) kg, median (range), time since injury = 1.09 (0.43–4.38) years) participated in this study. Participants were included in the study if they were: (1) between 18 and 60 years old and (2) had zero to minimal cognitive impairment. In addition, the mTBI participants were included if they had a diagnosis of mTBI based upon Department of Defense criteria [16] and were still self-reporting symptoms related to their mTBI. Exclusion criteria included: (1) any musculoskeletal, neurological, or sensory problems that could explain balance deficits (not including the mTBI); (2) moderate to severe substance-use disorder within the past month (Diagnostic and Statistical Manual-5); (3) being in pain during the evaluation (≥7/10 by patient subjective report); (4) pregnancy; and (5) inability to abstain from medications that could impair balance for 24 h prior to testing.

The study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the Oregon Health & Science University Institutional Review Board (IRB #17206). All participants provided written informed consent prior to commencing testing.
