Background: Single-leg balance (SLB) can be chronically impaired after low back pain (LBP). Impaired SLB is a risk factor for recurrent LBP and lower extremity injury. In the United States military, the special forces operator (SFO) deploys on high-risk missions under extreme conditions, and impaired SLB can potentially threaten SFO safety and mission success. Purpose: To compare SLB in fully …