title: Timed up and down stairs test: preliminary reliability and validity of a new measure of functional mobility.
abstract: OBJECTIVE
  The reliability and validity of a new test, the Timed Up and Down Stairs (TUDS), were examined in children with and without cerebral palsy (CP).
  
  
  METHODS
  A convenience sample of 47 children age eight to 14 years participated, 20 with CP and 27 with typical development (TD). Using intraclass correlation coefficients (ICC), interrater, intrarater, and test-retest reliability of the TUDS were examined by two raters simultaneously testing nine children, by one rater who then rescored at a later time a video of the testing of 24 children, and by one rater testing 25 children twice with a two-hour separation, respectively. Concurrent validity was examined using Spearman rank correlations between TUDS scores and performance on the Timed Up and Go (TUG), the Functional Reach Test (FRT), and a Timed One Legged Stance (TOLS), which were completed in a random order on all children. Construct validity was examined by correlation and Kruskal-Wallis analysis of variance of scores across ages and three functional level groups.
  
  
  RESULTS
  The TUDS demonstrated excellent intrarater, interrater, and test-retest reliability [ICC (2,1) > or =0.94] and moderate to high concurrent validity (Spearman r(s) = 0.78, -0.57, and -0.77, with the TUG, FRT, and TOLS, respectively). Age accounted for 37% and 56% of the variance in the TUDS for the TD group and for the Gross Motor Function Classification Scale level I CP group, respectively. Significant differences in TUDS scores were found between all three functional level groups.
  
  
  CONCLUSIONS
  The TUDS has adequate reliability and validity in children with and without CP and appears to complement current clinical measures of functional mobility and balance. Further investigations on across larger age ranges and samples are warranted.
authors.affiliation: Hong Kong Society of Rehabilitation--WHO Collaborating Centre for Rehabilitation, Hong Kong.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Zaino
authors.forename: Victoria Gocha
authors.initials: VG
authors.lastname: Marchese
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Westcott