The objective of this project is to compare a three-month supervised fitness centre-based exercise programme to a 3-month unsupervised home-based exercise programme on discharge from inpatient rehabilitation on improving cardiorespiratory fitness and psychosocial functioning in a traumatic brain injured population. We plan to carry out a multi-centre, assessor blinded, randomised controlled trial with a parallel group design to compare the two interventions. We hypothesise that the supervised fitness-centre based programme will provide significantly better outcomes, and that these gains will not only be evident on completion of the programme, but will be maintained on follow-up, thereby demonstrating that investment in a supervised exercise programme can provide beneficial long-term effects.