Clinical measures (10 meter walk test, 6 minute walk test, timed up-and-go test, gait analysis) A research staff supervised by a physical therapist will perform the functional assessment to the subject at the National University Hospital. The functional assessment consists of a 10 meter walk test, 6 minute walk test and a timed up-and-go test performed in a randomized order. The tester will not provide any assistance as the patient makes their way around the track, however, the tester will shadow the patient so as to attend to any problems should there be a need to.