Original research| Volume 101, ISSUE 2, P275-282, February 2020

Assessing the Validity and Reliability of a New Video Goniometer App for Measuring Joint Angles in Adults and Children

Published:August 26, 2019DOI:


      • Angles app is a valid and reliable tool for assessing joint angles.
      • Angles app can be used during static and dynamic activity for adults and children.
      • Angles app is an affordable and user-friendly tool for clinicians and researchers.
      • Angles app allows users to measure range of motion during meaningful activities across time.



      To assess the convergent validity and reliability of joint angle measurements from a new video goniometer iPhone/iPad application separately in adults, older and young children.




      Child care and university environments.


      Fifty-four adults (mean ± SD=22.5±4.5y), 20 older children (mean ± SD=10.9±2.2y), 20 younger children (mean ± SD=1.6±0.8y) (N=94).


      Adults and older children performed both standardized static positions and functional activities. Younger children performed only a functional activity protocol.

      Main Outcome Measures

      Joint angle measurements using the app were validated against a commercially validated two-dimensional goniometric software program. In addition, validity of the app was compared to a standard mechanical goniometer for the measurement of angles drawn on a white board. Intra- and interrater reliability were assessed through independent rescoring of videos.


      Correlations between joint angle estimates obtained from the app and goniometer software or a mechanical goniometer were positive and very strong (r>.900; P<.0001). The intraclass correlation coefficient (ICC) for repeated scoring from the app indicated excellent intra- and interrater reliability (ICC>.900).


      High correlations for repeated measures and comparison to gold standard angle measurement instruments suggest that the new app is a valid and reliable tool for assessing joint angles during functional activity. This tool may provide clinicians an inexpensive yet accurate method for quantification of movements and immediate feedback on range of motion during tasks in a natural environment.


      List of abbreviations:

      2D (two-dimensional), 3D (three-dimensional), 95% CI (95% confidence interval), ICC (intraclass correlation coefficient)
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Archives of Physical Medicine and Rehabilitation
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Padulo J.
        • Vando S.
        • Chamari K.
        • Chaouachi A.
        • Bagno D.
        • Pizzolato F.
        Validity of the MarkWiiR for kinematic analysis during walking and running gaits.
        Biol Sport. 2015; 32: 53-58
        • Williams M.A.
        • McCarthy C.J.
        • Chorti A.
        • Cooke M.W.
        • Gates S.
        A systematic review of reliability and validity studies of methods for measuring active and passive cervical range of motion.
        J Manipulative Physiol Ther. 2010; 33: 138-155
        • Zhou H.
        • Hu H.
        Human motion tracking for rehabilitation - a survey.
        Biomed Signal Process Control. 2008; 3: 1-18
        • Damsted C.
        • Nielsen R.O.
        • Larsen L.H.
        Reliability of video-based quantification of the knee- and hip angle at foot strike during running.
        Int J Sports Phys Ther. 2015; 10: 147-154
        • Littrell M.E.
        • Chang Y.H.
        • Selgrade B.P.
        Development and assessment of a low-cost clinical gait analysis system.
        J Appl Biomech. 2018; 10: 1-19
        • Krosshaug T.
        • Nakamae A.
        • Boden B.
        • et al.
        Estimating 3D joint kinematics from video sequences of running and cutting maneuvers--assessing the accuracy of simple visual inspection.
        Gait Posture. 2007; 26: 378-385
        • Churchill A.
        • Halligan P.W.
        • Wade D.T.
        RIVCAM: a simple video-based kinematic analysis for clinical disorders of gait.
        Comput Methods Programs Biomed. 2002; 69: 197-209
        • Cornwall M.
        • McPoil T.G.
        Comparison of 2-dimensional and 3-dimensional rearfoot motion during walking.
        Clin Biomech. 1995; 10: 36-40
        • Fortin C.
        • Feldman D.E.
        • Cheriet F.
        • Labelle H.
        Validity of a quantitative clinical measurement tool of trunk posture in idiopathic scoliosis.
        Spine. 2010; 35: E988-E994
        • Baude M.
        • Hutin E.
        • Gracies J.M.
        A bidimensional system of facial movement analysis conception and reliability in adults.
        Biomed Res Int. 2015; 2015: 812961
        • Balsalobre-Fernandez C.
        • Tejero-Gonzalez C.M.
        • Campo-Vecino J.D.
        • Balsalobre-Fernandez C.
        • Bavaresco N.
        The concurrent validity and reliability of a low-cost, high-speed camera-based method for measuring the flight time of vertical jumps.
        J Strength Cond Res. 2014; 28: 528-533
        • Moral-Muñoz J.A.
        • Esteban-Moreno B.
        • Arroyo-Morales M.
        • Cobo M.J.
        • Herrera-Viedma E.
        Agreement between face-to-face and free software video analysis for assessing hamstring flexibility in adolescents.
        J Strength Cond Res. 2015; 29: 2661-2665
        • Kamaci S.
        • Yucekul A.
        • Demirkiran G.
        • Berktas M.
        • Yazici M.
        The evolution of sagittal spinal alignment in sitting position during childhood.
        Spine. 2015; 40: E787-E793
        • Ludwig O.
        • Hammes A.
        • Kelm J.
        • Schmitt E.
        Assessment of the posture of adolescents in everyday clinical practice: intra-rater and inter-rater reliability and validity of a posture index.
        J Bodyw Mov Ther. 2016; 20: 761-766
        • Williams C.M.
        • Caserta A.J.
        • Haines T.P.
        The TiltMeter app is a novel and accurate measurement tool for the weight bearing lunge test.
        J Sci Med Sport. 2013; 16: 392-395
        • Reese N.B.
        • Bandy W.D.
        • Yates C.
        Joint range of motion and muscle length testing.
        Saunders/Elsevier, St. Louis, MO2010
        • Gajdosik R.L.
        • Bohannon R.W.
        Clinical measurement of range of motion. Review of goniometry emphasizing reliability and validity.
        Phys Ther. 1987; 67: 1867-1872
        • Lee A.L.
        • Zabjek K.
        • Goldstein R.S.
        • Brooks D.
        Systematic review of postural assessment in individuals with obstructive respiratory conditions.
        J Cardiopulm Rehabil Prev. 2017; 37: 90-102
        • Pearl M.L.
        • van de Bunt F.
        • Pearl M.
        • Lightdale-Miric N.
        • Rethlefsen S.
        • Loiselle J.
        Assessing shoulder motion in children: age limitations to Mallet and ABC Loops.
        Clin Orthop Relat Res. 2014; 472: 740-748
        • Jones A.
        • Sealey R.
        • Crowe M.
        • Gordon S.
        Concurrent validity and reliability of the Simple Goniometer iPhone app compared with the Universal Goniometer.
        Physiother Theory Pract. 2014; 30: 512-516
        • Otter S.J.
        • Agalliu B.
        • Baer N.
        • et al.
        The reliability of a smartphone goniometer application compared with a traditional goniometer for measuring first metatarsophalangeal joint dorsiflexion.
        J Foot Ankle Res. 2015; 23: 30
        • Vohralik S.L.
        • Bowen A.R.
        • Burns J.
        • Hiller C.E.
        • Nightingale E.J.
        Reliability and validity of a smartphone app to measure joint range.
        Am J Phys Med Rehabil. 2015; 94: 325-330
        • Cox R.W.
        • Martinez R.E.
        • Baker R.T.
        • Warren L.
        Validity of a smartphone application for measuring ankle plantar flexion.
        J Sport Rehabil. 2018; 27
        • Milanese S.
        • Gordon S.
        • Buettner P.
        • et al.
        Reliability and concurrent validity of knee angle measurement: smart phone app versus universal goniometer used by experienced and novice clinicians.
        Man Ther. 2014; 19: 569-574
        • Pourahmadi M.R.
        • Bagheri R.
        • Taghipour M.
        • Takamjani I.E.
        • Sarrafzadeh J.
        • Mohseni-Bandpei M.A.
        A new iPhone application for measuring active craniocervical range of motion in patients with non-specific neck pain: a reliability and validity study.
        Spine J. 2018; 18: 447-457
        • Quek J.
        • Brauer S.G.
        • Treleaven J.
        • Pua Y.H.
        • Mentiplay B.
        • Clark R.A.
        Validity and intra-rater reliability of an Android phone application to measure cervical range-of-motion.
        J Neuroeng Rehabil. 2014; 11: 65
        • Tousignant-Laflamme Y.
        • Boutin N.
        • Dion A.M.
        • Vallee C.A.
        Reliability and criterion validity of two applications of the iPhone to measure cervical range of motion in healthy participants.
        J Neuroeng Rehabil. 2013; 10: 69
        • Walicka-Cuprys K.
        • Drzal-Grabiec J.
        • Mrozkowiak M.
        Comparison of parameters of spinal curves in the sagittal plane measured by photogrammetry and inclinometry.
        Ortop Traumatol Rehabil. 2013; 15: 429-437
        • Mehta S.P.
        • Barker K.
        • Bowman B.
        • Galloway H.
        • Oliashirazi N.
        • Oliashirazi A.
        Reliability, concurrent validity, and minimal detectable change for iPhone goniometer app in assessing knee range of motion.
        J Knee Surg. 2017; 30: 577-584
        • Pereira L.C.
        • Rwakabayiza S.
        • Lecureux E.
        • Jolles B.M.
        Reliability of the knee smartphone-application goniometer in the acute orthopedic setting.
        J Knee Surg. 2017; 30: 223-230
        • Stove M.P.
        • Palsson T.S.
        • Hirata R.P.
        Smartphone-based accelerometry is a valid tool for measuring dynamic changes in knee extension range of motion.
        Knee. 2018; 25: 66-72
        • Faul F.
        • Erdfelder E.
        • Lang A.G.
        • Buchner A.
        G*Power 3: a flexible statistical power analysis program for the social, behavioral, and biomedical sciences.
        Behav Res Methods. 2007; 39: 175-191
        • Da Costa C.S.
        • Rocha N.A.
        Sit-to-stand movement in children: a longitudinal study based on kinematics data.
        Hum Mov Sci. 2013; 32: 836-846
        • Fees B.S.
        • Fischer E.
        • Haar S.
        • Crowe L.K.
        Toddler activity intensity during indoor free-play: stand and watch.
        J Nutr Educ Behav. 2015; 47: 170-175
        • Harbourne R.T.
        • Lobo M.A.
        • Karst G.M.
        • Galloway J.C.
        Sit happens: does sitting development perturb reaching development, or vice versa?.
        Infant Behav Dev. 2013; 36: 438-450
        • Lobo M.A.
        • Kokkoni E.
        • de Campos A.C.
        • Galloway J.C.
        Not just playing around: infants' behaviors with objects reflect ability, constraints, and object properties.
        Infant Behav Dev. 2014; 37: 334-351
        • Krause D.A.
        • Boyd M.S.
        • Hager A.N.
        • Smoyer E.C.
        • Thompson A.T.
        • Hollman J.H.
        Reliability and accuracy of a goniometer mobile device application for video measurement of the functional movement screen deep squat test.
        Int J Sports Phys Ther. 2015; 10: 37-44
        • Portney L.G.
        • Watkins M.P.
        Foundations of clinical research: applications to practice.
        3rd ed. Prentice Hall Health, Upper Saddle River, NJ2009
        • Field A.P.
        Discovering statistics using IBM SPSS statistics.
        4th ed. SAGE Publications Ltd, Washington, DC2013
        • Norkin C.C.
        • White D.J.
        Measurement of joint motion: a guide to goniometry.
        FA Davis Company, Philadelphia2009
        • Furness J.
        • Schram B.
        • Cox A.J.
        • Anderson S.L.
        • Keogh J.
        Reliability and concurrent validity of the iPhone® Compass application to measure thoracic rotation range of motion (ROM) in healthy participants.
        PeerJ. 2018; 6e4431
        • Pourahmadi M.R.
        • Ebrahimi Takamjani I.
        • Sarrafzadeh J.
        • et al.
        Reliability and concurrent validity of a new iPhone® goniometric application for measuring active wrist range of motion: a cross-sectional study in asymptomatic subjects.
        J Anat. 2017; 230: 484-495
        • Morales C.R.
        • Lobo C.C.
        • Sanz D.R.
        • Corbalan I.S.
        • Ruiz B.R.
        • Lopez D.L.
        The concurrent validity and reliability of the leg motion system for measuring ankle dorsiflexion range of motion in older adults.
        PeerJ. 2017; 5e2820