title: Assessing the reliability and validity of a shorter walk test compared with the 10-Meter Walk Test for measurements of gait speed in healthy, older adults.
abstract: OBJECTIVE
  Walking speed is associated with several health-related outcomes. Research examining how differences in test walking distance affect walking speed reliability and validity is limited. The primary purpose of this study was to examine the reliability and concurrent validity of gait speed measurements obtained from a 4-Meter Walk Test compared with the commonly used 10-Meter Walk Test. A second objective was to similarly examine 2 different timing methods: stopwatch and automatic timers.
  
  
  METHODS
  Forty-three healthy, older adults (mean age = 84.3 ± 6.9 years) performed 3 consecutive walking trials on the 4- and 10-Meter Walk Tests at their self-selected walking speed.
  
  
  RESULTS
  Gait speed measurements for both tests were shown to have excellent test-retest reliability (ICC values of 0.96-0.98), with similar results for stopwatch and automatic timer assessments (ICC values of 0.99-1.00). Standard error of the measurement (SEM) values were small (0.004-0.008 m/s) across measurement methods. While the ICC value for gait speed measurements between the 2 walk tests was 0.93, the Bland-Altman analysis revealed a discrepancy of ±0.15 to ±0.17 m/s between measurement methods.
  
  
  CONCLUSIONS
  Both 4- and 10-m gait speed assessments had excellent test-retest reliability with similar SEM and minimal detectable change values. There was little difference in SEM values between the 2 timing methods. While the mean difference in gait speed between the 4- and 10-Meter Walk Tests was small, the range of the measurement differences was large enough to potentially mask meaningful changes in gait speed over time if both methods were used interchangeably.
  
  
  CONCLUSIONS
  While the reliability of both walking tests is excellent, the 4-Meter Walk Test does not exhibit a high enough degree of concurrent validity with the 10-Meter Walk Test to be used interchangeably for gait speed assessments in healthy, older adults. We therefore recommend using the 10-Meter Walk Test to obtain the most valid clinical assessment of walking speed when using it as a 1-time indicator of health status.
authors.affiliation: Department of Exercise Science, University of South Carolina, Columbia, SC 29208, USA. petersd20@gmail.com
authors.forename: Denise M
authors.initials: DM
authors.lastname: Peters
authors.forename: Stacy L
authors.initials: SL
authors.lastname: Fritz
authors.forename: Debra E
authors.initials: DE
authors.lastname: Krotish
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D003430:Cross-Sectional Studies; D005080:Exercise Test / Q000379:methods*; D005260:Female; D005684:Gait; D015577:Geriatric Assessment / Q000379:methods*; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D016138:Walking