Prognostic value of usual gait speed in well-functioning older people-results from the Health, Aging and Body Composition Study - Cesari, M; Kritchevsky, S B; Penninx, B W; Nicklas, B J; Simonsick, E M; Newman, A B; Tylavsky, F A; Brach, J S; Satterfield, S; Bauer, D C; Visser, M; Rubin, S M; Harris, T B; Pahor, M (J Am Geriatr Soc, 2005)