1. Research and Development Service, Washington DC Veterans Affairs Medical Center, Washington, District of Columbia, United States
2. Department of Health, Human Function, and Rehabilitation Sciences, The George Washington University, Washington, District of Columbia, United States
3. Department of Medicine, University of Maryland, Baltimore, Maryland, United States
4. Division of Geriatrics and Palliative Medicine, Baltimore Veterans Affairs Medical Center, Baltimore, Maryland, United States
5. Department of Medicine, Washington DC Veterans Affairs, Medical Center, Washington, District of Columbia, United States
6. Department of Medicine, The George Washington University, Washington, District of Columbia, United States
7. Division of Cardiology, Washington DC Veterans Affairs Medical Center, Washington, District of Columbia, United States
8. Department of Kinesiology and Health, Rutgers University, New Brunswick, New Jersey, United States
9. Department of Physical Medicine and Rehabilitation, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
10. Geriatric Research Education and Clinical Center, Eastern Colorado Veterans Affairs Health Care System, Denver, Colorado, United States
11. Physical Medicine and Rehabilitation Service, Washington DC Veterans Affairs Medical Center, Washington, District of Columbia, United States
12. Department of Medicine, Georgetown University, Washington, District of Columbia, United States
13. Department of Rehabilitation Medicine, Georgetown University, Washington, District of Columbia, United States