title: Physical Activity and Change in Long Distance Corridor Walk Performance in the Health, Aging, and Body Composition Study.
abstract: OBJECTIVE
  To examine the prospective relationship between self-reported physical activity and aerobic fitness in the Health, Aging, and Body Composition Study (Health ABC) using the Long Distance Corridor Walk (LDCW).
  
  
  METHODS
  Cohort study with 7 years of follow-up.
  
  
  METHODS
  Two U.S. clinical sites.
  
  
  METHODS
  Community-dwelling older adults enrolled in Health ABC (N = 3,075, aged 70-79, 52% female, 42% black) with no self-reported difficulty walking one-quarter of a mile or climbing 10 steps.
  
  
  METHODS
  Participants were classified based on a physical activity questionnaire as being inactive (≤1,000 kcal/wk exercise activity, ≤2,719 kcal/wk total physical activity), lifestyle active (≤1,000 kcal/wk exercise activity, >2,719 kcal/wk total physical activity), or exercisers (≥1,000 kcal/wk exercise activity). The LDCW, an endurance walking test (400 m), was administered at Years 1 (baseline), 2, 4, 6, and 8 to assess aerobic fitness.
  
  
  RESULTS
  At baseline, LDCW completion times (adjusted for age and sex) were 351.8 seconds (95% confidence interval (CI) = 346.9-356.8 seconds) for the inactive group, 335.9 seconds (95% CI = 332.7-339.1 seconds) for the lifestyle active group, and 307.7 seconds (95% CI = 303.2-312.3 seconds) for the exerciser group (P < .001). From baseline to Year 8, the inactive group slowed 36.1 seconds (95% CI = 28.4-43.8 seconds), the lifestyle active group slowed 38.1 seconds (95% CI = 33.6-42.4 seconds), and the exerciser group slowed 40.8 seconds (95% CI = 35.2-46.5 seconds), and did not differ significantly between groups. In linear mixed-effects models, the rate of change in LDCW time did not differ between the groups, although exercisers consistently had the fastest completion times (P < .001 for all pairwise comparisons).
  
  
  CONCLUSIONS
  Decline in LDCW time occurred regardless of baseline activity, although exercisers maintained higher aerobic fitness, which may delay reaching a critically low threshold of aerobic fitness at which independence is impaired.
authors.affiliation: Center for Aging and Population Health, Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Brittney S
authors.initials: BS
authors.lastname: Lange-Maia
authors.affiliation: Center for Aging and Population Health, Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Elsa S
authors.initials: ES
authors.lastname: Strotmeyer
authors.affiliation: Intramural Research Program, Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Bethesda, Maryland.
authors.forename: Tamara B
authors.initials: TB
authors.lastname: Harris
authors.affiliation: Center for Aging and Population Health, Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Nancy W
authors.initials: NW
authors.lastname: Glynn
authors.affiliation: Intramural Research Program, National Institute on Aging, Baltimore, Maryland.
authors.forename: Eleanor M
authors.initials: EM
authors.lastname: Simonsick
authors.affiliation: Department of Physical Therapy, School of Health and Rehabilitation Science, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Brach
authors.affiliation: Center for Aging and Population Health, Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Jane A
authors.initials: JA
authors.lastname: Cauley
authors.affiliation: Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Phyllis A
authors.initials: PA
authors.lastname: Richey
authors.affiliation: Department of Epidemiology and Biostatistics, University of California at San Francisco, San Francisco, California.
authors.forename: Ann V
authors.initials: AV
authors.lastname: Schwartz
authors.affiliation: Center for Aging and Population Health, Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Anne B
authors.initials: AB
authors.lastname: Newman
mesh_terms: D000368:Aged; D001823:Body Composition; D015331:Cohort Studies; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D010414:Pennsylvania; D010807:Physical Endurance / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*; D011795:Surveys and Questionnaires; D013714:Tennessee; D014481:United States; D016138:Walking / Q000502:physiology*
keywords: 400-m walk; aerobic fitness; physical activity