3D Back Shape in Healthy Young Adults: An Inter-rater and Intra-rater Reliability Study b c a Physiotherapist, Darlington Memorial Hospital, Hollyhurst Road, Darlington, DL3 6HX b Senior Lecturer in Research Methodology, School of Health and Social Care c Senior Lecturer, School of Computing, University of Teesside, Borough Road, Middlesbrough, TS1 3BA, UK Abstract: Whilst postural evaluation of spinal dysfunction is routine in physiotherapy practice, objective measurements are rarely undertaken due to the scarcity of reliable low cost assessment tools. Warren et al [12] found high intra- rater reliability but inter-rater reliability has not as yet been evaluated. The purpose of this study was to assess both the intra-rater and inter-rater reliability of the Middlesbrough Integrated Digital Assessment system (MIDAS). Methods: A convenience sample of twenty-five healthy University of Teesside students was recruited for the study. One rater palpated fifteen key landmarks on each subjects back. Each of three raters took two measurements on each subject in a standardized upright posture. Rater order was randomized to minimize data recording bias. X (medio-lateral), Y (antero-posterior) and Z (height) landmark positions were recorded via a computer interface. Data Analysis: Intraclass Correlation Coefficients (ICC 2,1) were used to analyse data using SPSS v13. Results: Both intra-rater agreement (mean ICCs - rater 1 r= 0.970, rater 2 r= 0.965 and rater 3 r= 0.965, p<0.001) and inter-rater agreement (mean ICCs r = 0.967, p<0.001 was very high between repeated measures and between markers. Error values for the z-axis (height) were lowest. Conclusions: The system demonstrated both high inter-rater and intra-rater reliability. Before the system is used on a clinical population, data output needs to be converted from raw format to a clinically applicable format. Work is currently being undertaken to develop an interactive visual display and control for postural sway. Keywords: Posture assessment, evidence-based practice, low-cost system Introduction Low back pain (LBP) is a common musculoskeletal health problem treated by health professionals [1] and is one of the largest causes of compensation claims in the workplace [2]. Retraining of posture is a traditionally integral physiotherapeutic intervention in the treatment of back pain [3] and the benefit of postural correction exercises for the relief of back pain has previously been studied [4, 5, 6, 7]. Despite much research being devoted to postural retraining and the general acknowledgement a McALPINE R.T. , BETTANY-SALTIKOV J.A. and WARREN J.G. Research into Spinal Deformities 5 D. Uyttendaele and P.H. Dangerfield (Eds.) IOS Press, 2006 © 2006 The authors. All rights reserved. 505