title: Mobility limitation in self-described well-functioning older adults: importance of endurance walk testing.
abstract: BACKGROUND
  Mobility limitations are prevalent, potentially reversible precursors to mobility loss that may go undetected in older adults. This study evaluates standardized administration of an endurance walk test for identifying unrecognized and impending mobility limitation in community elders.
  
  
  METHODS
  Men and women (1480 and 1576, respectively) aged 70-79 years with no reported mobility limitation participating in the Health, Aging and Body Composition study were administered the Long Distance Corridor Walk. Walk performance was examined to determine unrecognized mobility deficits at baseline and predict new self-recognition of mobility limitation within 2 years.
  
  
  RESULTS
  On testing, 23% and 36% of men and women evidenced mobility deficits defined as a contraindication to exertion, meeting stopping criteria or exceeding 7 minutes to walk 400 m. Unrecognized deficits increased with age and were more prevalent in blacks, smokers, obese individuals, and infrequent walkers. Within 2 years, 21% and 34% of men and women developed newly recognized mobility limitation; those with baseline unrecognized deficits had higher rates, 40% and 54% (p <.001), respectively. For each additional 30 seconds over 5 minutes needed to walk 400 m, likelihood of newly recognized mobility limitation increased by 65% and 37% in men and women independent of age, race, obesity, smoking status, habitual walking, reported walking ease, and usual gait speed.
  
  
  CONCLUSIONS
  A sizable proportion of elders who report no walking difficulty have observable deficits in walking performance that precede and predict their recognition of mobility limitation. Endurance walk testing can help identify these deficits and provide the basis for treatment to delay progression of mobility loss.
authors.affiliation: Clinical Research Branch, National Institute on Aging, Harbor Hospital-NIA-ASTRA Unit, 3001 S. Hanover St. Baltimore, MD 21225, USA. simonsickel@mail.nih.gov
authors.forename: Eleanor M
authors.initials: EM
authors.lastname: Simonsick
authors.forename: Anne B
authors.initials: AB
authors.lastname: Newman
authors.forename: Marjolein
authors.initials: M
authors.lastname: Visser
authors.forename: Bret
authors.initials: B
authors.lastname: Goodpaster
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kritchevsky
authors.forename: Susan
authors.initials: S
authors.lastname: Rubin
authors.forename: Michael C
authors.initials: MC
authors.lastname: Nevitt
authors.forename: Tamara B
authors.initials: TB
authors.lastname: Harris
mesh_terms: D000368:Aged; D015331:Cohort Studies; D004185:Disability Evaluation; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D051346:Mobility Limitation; D015999:Multivariate Analysis; D010807:Physical Endurance / Q000502:physiology*; D016138:Walking / Q000502:physiology*
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