title: Arch height change during sit-to-stand: an alternative for the navicular drop test.
abstract: BACKGROUND
  A study was conducted to determine the reliability and validity of a new foot mobility assessment method that utilizes digital images to measure the change in dorsal arch height measured at 50% of the length of the foot during the Sit-to-Stand test.
  
  
  METHODS
  Two hundred - seventy five healthy participants participated in the study. The medial aspect of each foot was photographed with a digital camera while each participant stood with 50% body weight on each foot as well as in sitting for a non-weight bearing image. The dorsal arch height was measured at 50% of the total length of the foot on both weight bearing and non-weight bearing images to determine the change in dorsal arch height. The reliability and validity of the measurements were then determined.
  
  
  RESULTS
  The mean difference in dorsal arch height between non-weight bearing and weight bearing was 10 millimeters. The change in arch height during the Sit-to-Stand test was shown to have good to high levels of intra- and inter-reliability as well as validity using x-rays as the criterion measure.
  
  
  CONCLUSIONS
  While the navicular drop test has been widely used as a clinical method to assess foot mobility, poor levels of inter-rater reliability have been reported. The results of the current study suggest that the change in dorsal arch height during the Sit-to-Stand test offers the clinician a reliable and valid alternative to the navicular drop test.
authors.affiliation: Gait Research Laboratory, Program in Physical Therapy, Northern Arizona University, Flagstaff, Arizona, USA. tom.mcpoil@nau.edu.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: McPoil
authors.forename: Mark W
authors.initials: MW
authors.lastname: Cornwall
authors.forename: Lynn
authors.initials: L
authors.lastname: Medoff
authors.forename: Bill
authors.initials: B
authors.lastname: Vicenzino
authors.forename: Kelly
authors.initials: K
authors.lastname: Forsberg
authors.forename: Dana
authors.initials: D
authors.lastname: Hilz