- Inability to walk for 2 minutes; the rationale being that people who cannot walk for 2 minutes would not be able to complete the necessary submaximal treadmill test, which is used to screen for coronary ischemic symptoms. We will also exclude anyone who can walk for 20 minutes or more during the submaximal treadmill test. Anyone who can complete the submaximal test would not have significant walking impairment and would not get that much out of the study.