Evaluating the efficacy of a personalised sub-symptomatic exercise treatment programme for rehabilitation of military service members with persistent symptoms following mild traumatic brain injury: a randomised controlled trial

Mild traumatic brain injury (mTBI) remains a significant health concern for the US Military Health System and a threat to warfighter readiness. Although most service members (SMs) recover following an initial period of rest and a progressive return-to-activity protocol, a subset experience persistent cognitive, psychological and physical symptoms lasting months to years post-injury. Sub-symptomatic exercise has demonstrated efficacy in reducing exercise intolerance and expediting recovery in athletes with mTBI. Given differences in injury mechanisms between athletes and SMs, including blast exposure, it is unclear whether similar benefits extend to military populations with chronic post-concussive symptoms. This prospective, randomised controlled trial will evaluate the efficacy of an adaptable, sub-symptomatic exercise treatment (ASSET) programme compared with a mobility active control (MAC) intervention in SMs with chronic mTBI symptoms. A total of 140 active-duty SMs with a history of mTBI per Department of Defense criteria and persistently elevated neurobehavioural symptoms more than 1 month post-injury will be enrolled. Following screening and informed consent, participants will be randomised to ASSET or MAC and undergo baseline assessment. Outcomes will be assessed immediately postintervention (approximately 8 weeks) and at 3 months post-treatment. The primary outcome is neurobehavioural symptom resolution. Secondary and exploratory outcomes include cognitive performance, physiological adaptation, locomotion and military-relevant functional performance. Statistical analyses will examine group differences over time to determine treatment effects.