title: Validity and intra-rater reliability of an android phone application to measure cervical range-of-motion.
abstract: BACKGROUND
  Concurrent validity and intra-rater reliability using a customized Android phone application to measure cervical-spine range-of-motion (ROM) has not been previously validated against a gold-standard three-dimensional motion analysis (3DMA) system.
  
  
  RESULTS
  Twenty-one healthy individuals (age:31 ± 9.1 years, male:11) participated, with 16 re-examined for intra-rater reliability 1-7 days later. An Android phone was fixed on a helmet, which was then securely fastened on the participant's head. Cervical-spine ROM in flexion, extension, lateral flexion and rotation were performed in sitting with concurrent measurements obtained from both a 3DMA system and the phone.The phone demonstrated moderate to excellent (ICC = 0.53-0.98, Spearman ρ = 0.52-0.98) concurrent validity for ROM measurements in cervical flexion, extension, lateral-flexion and rotation. However, cervical rotation demonstrated both proportional and fixed bias. Excellent intra-rater reliability was demonstrated for cervical flexion, extension and lateral flexion (ICC = 0.82-0.90), but poor for right- and left-rotation (ICC = 0.05-0.33) using the phone. Possible reasons for the outcome are that flexion, extension and lateral-flexion measurements are detected by gravity-dependent accelerometers while rotation measurements are detected by the magnetometer which can be adversely affected by surrounding magnetic fields.
  
  
  CONCLUSIONS
  The results of this study demonstrate that the tested Android phone application is valid and reliable to measure ROM of the cervical-spine in flexion, extension and lateral-flexion but not in rotation likely due to magnetic interference. The clinical implication of this study is that therapists should be mindful of the plane of measurement when using the Android phone to measure ROM of the cervical-spine.
authors.forename: June
authors.initials: J
authors.lastname: Quek
authors.forename: Sandra G
authors.initials: SG
authors.lastname: Brauer
authors.forename: Julia
authors.initials: J
authors.lastname: Treleaven
authors.forename: Yong-Hao
authors.initials: YH
authors.lastname: Pua
authors.forename: Benjamin
authors.initials: B
authors.lastname: Mentiplay
authors.affiliation: School of Exercise Science, Faculty of Health Sciences, Australian Catholic University, Fitzroy, Victoria 3065, Australia. ross.clark@acu.edu.au.
authors.forename: Ross Allan
authors.initials: RA
authors.lastname: Clark
mesh_terms: D000328:Adult; D040421:Cell Phone; D002574:Cervical Vertebrae / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D063731:Mobile Applications; D009333:Neck / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology*; D015203:Reproducibility of Results
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