title: The TiltMeter app is a novel and accurate measurement tool for the weight bearing lunge test.
abstract: OBJECTIVE
  The weight bearing lunge test is increasing being used by health care clinicians who treat lower limb and foot pathology. This measure is commonly established accurately and reliably with the use of expensive equipment. This study aims to compare the digital inclinometer with a free app, TiltMeter on an Apple iPhone.
  
  
  METHODS
  This was an intra-rater and inter-rater reliability study. Two raters (novice and experienced) conducted the measurements in both a bent knee and straight leg position to determine the intra-rater and inter-rater reliability. Concurrent validity was also established.
  
  
  METHODS
  Allied health practitioners were recruited as participants from the workplace. A preconditioning stretch was conducted and the ankle range of motion was established with the weight bearing lunge test position with firstly the leg straight and secondly with the knee bent. The measurement device and each participant were randomised during measurement.
  
  
  RESULTS
  The intra-rater reliability and inter-rater reliability for the devices and in both positions were all over ICC 0.8 except for one intra-rater measure (Digital inclinometer, novice, ICC 0.65). The inter-rater reliability between the digital inclinometer and the tilmeter was near perfect, ICC 0.96 (CI: 0.898-0.983); Concurrent validity ICC between the two devices was 0.83 (CI: -0.740 to 0.445).
  
  
  CONCLUSIONS
  The use of the Tiltmeter app on the iPhone is a reliable and inexpensive tool to measure the available ankle range of motion. Health practitioners should use caution in applying these findings to other smart phone equipment if surface areas are not comparable.
authors.affiliation: Southern Health, Allied Health Clinical Research Unit, Kingston Centre, Cheltenham, Victoria, Australia. Cylie.Williams@southernhealth.org.au
authors.forename: Cylie M
authors.initials: CM
authors.lastname: Williams
authors.forename: Antoni J
authors.initials: AJ
authors.lastname: Caserta
authors.forename: Terry P
authors.initials: TP
authors.lastname: Haines
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D063731:Mobile Applications; D015588:Observer Variation; D016059:Range of Motion, Articular
keywords: Ankle; Biomedical technology; Joint range of motion; Reliability and validity