VO2MAX, 6-minute walk, and muscle strength each correlate with frailty in US veterans oleh Kenneth Ladd Seldeen, Kenneth Ladd Seldeen, Ayesha Saqebur Rahman, Yonas Redae, Nikhil Satchidanand, M. Jeffery Mador, M. Jeffery Mador, Changxing Ma, Mihir Soparkar, Alexis Rose Lima, Ifeoma N. Ezeilo, Bruce Robert Troen, Bruce Robert Troen