Effects of Rapid-Resisted Exercise and Bright Light Therapy on Ambulatory Adults With Traumatic Brain Injury

Background: * Traumatic brain injury may have a range of effects, from severe and permanent disability to more subtle functional and cognitive deficits that often go undetected during initial treatment. To improve treatments and therapies and to provide a uniform quality of care, more research is needed into different treatments for traumatic brain injury. * Exercise has been shown to improve movement and balance in people with strokes, cerebral palsy, and other conditions that affect the brain, and can improve symptoms of memory problems or depression. Bright light therapy has also been shown to improve mood in people with depression. Researchers are interested in studying problems with movement, balance, thinking, and mood in people with traumatic brain injury. By comparing the effects of exercise and bright light exposure on brain function, new treatments may be developed for acute traumatic brain injury. Objectives: \- To compare the effects of exercise and bright light therapy on the brain function of individuals with traumatic brain injury. Eligibility: \- Individuals between 18 and 44 years of age who either have been diagnosed with traumatic brain injury or are healthy volunteers. Design: * Individuals with traumatic brain injury will have four outpatient evaluation visits at the clinical center, a 3-month home exercise program, and a 3-month bright light exposure program at home. Healthy volunteers will have one evaluation visit at the clinical center. * At the first study visit, all participants will have a full physical examination and medical history. Individuals with traumatic brain injury will also have an eye exam to determine if it is safe for them to receive light therapy. * All participants will have the following initial tests: * Tests of walking and movement, including monitoring by a physical therapist; tests to record joint movement and evaluate muscle function; tests that combine movement, thinking, and speaking; and balance and reactio