 The purpose of this study is to determine the value of Constraint-Induced Movement therapy CIMT for improving motor function and general fitness in adults with subacute and chronic traumatic brain injury TBI, particularly TBI acquired during active military duty, in comparison to a Lakeshore Enriched Fitness Training LEFT. The study will also test the effect of a set of enhanced versus standard procedures for transferring therapeutic gains from treatment setting to everyday life. Lastly, this study will determine whether any therapeutic effects observed are correlated with neuroplastic white matter or grey matter changes. 