Inclusion Criteria:  Pilot Cohort  Active duty Service members cleared for full physical activity. 18-44 years old  Uninjured Cohort  Active duty Service members cleared for full physical activity. Recruited within 14 days following the in-processing medical screening. 18-44 years old  Injured Cohort  Active duty Service members receiving conservative treatment exclusively for a musculoskeletal injury affecting the low back or lower extremity. Recruited within 3 days following presentation to the physical therapy clinic for care of the MSKI of interest. 18-44 years old  Exclusion Criteria:  Pilot Cohort  Currently on limited duty status, for any reason. Unable to read or comprehend the English language. Pregnant females (will be eligible for participation in the study after the pregnancy)  Uninjured Cohort  Currently on limited duty status, for any reason. Scheduled for a deployment or separation from current unit within the next 12 months. Unable to read or comprehend the English language. Pregnant females (will be eligible for participation in the study after the pregnancy)  Injured Cohort  Unable to read or comprehend the English language. A MSKI within the last 6 months. History of musculoskeletal related surgery. History of traumatic brain injury within the preceding 2 years. Pregnant females (will be eligible for participation in the study after the pregnancy)