The refinement and validity evaluation of a 2-Dimensional motion capture method to quantify lumbo-pelvic-hip complex motion in chronic low back pain. Peter James Window Bachelor of Physiotherapy A thesis submitted for the degree of Doctor of Philosophy at The University of Queensland in 2017 The School of Health and Rehabilitation Sciences Abstract Aberrant movement control of the lumbo-pelvic-hip complex is a feature of musculoskeletal conditions such as low back pain. There is evidence of altered movement control of the pelvis in multiple planes in individuals with chronic low back pain (CLBP). As a result, accurate assessment of motion control in conditions such as CLBP is required to assist diagnostics and management planning particularly with regard to therapeutic exercise. While 3-dimensional (3D) motion capture is the gold standard motion measurement, cost restraints and technical expertise requirements associated with 3D methods prevent accessibility in most clinical setting. Instead 2-dimensional (2D) video and photographic methods to assess movement control are increasingly being used in clinical settings. Despite the widespread use of these clinical measurement methods, the reliability and validity of measurements made using 2D methods has not been well established. The use of 2D methods for evaluating motion of the lumbo-pelvic-hip region is further limited by difficulties in capturing angular displacement of the pelvis in the transverse plane without the use of an overhead camera. The aim of this thesis was to address methodological issues and knowledge gaps concerning 2D methods of motion capture of the lumbo-pelvic- hip complex. Specifically the thesis systematically explored current knowledge regarding the reliability and validity of movement control tests to assess the lumbo-pelvic-hip complex; developed a novel 2D method of measuring pelvic rotation in the transverse plane without an overhead camera; and investigated the validity and reliability of the refined 2D motion capture method by comparing its accuracy to a gold standard 3D method, as well as exploring its capacity to detect aberrant, and potentially clinically relevant, lumbo-pelvic-hip motion differences in those with and without CLBP. In Study 1 current literature was systematically reviewed with respect to the reliability of motion control measurements during commonly reported movement control tests of the lumbo-pelvic-hip complex. In particular measurement reliability was considered for both quantitative and clinician-based subjective rating methods. A further aspect of the systematic review was to explore the validity of the motion measures as a measure of gluteal muscle function by determining their relationship with other measures of gluteal muscle function. Given the anatomical and biomechanical relationship of the gluteal muscles in controlling motion of the pelvis and hip, movement control tests of the lumbo- pelvic-hip complex are commonly touted as measures of gluteal function. The review 1 demonstrated that although reliability of the measures varied widely, quantitative methods tended to demonstrate higher levels of reliability than clinician ratings. Inconsistent relationships between test performance and quantitative measures of gluteal muscle function were observed, with the exception of strong evidence for a relationship between hip external rotation strength and frontal plane knee movement during a single-leg squat. The findings of this review strengthen the need for more clinically accessible quantitative measurement methods for the assessment of movement control of the lumbo-pelvic-hip complex. It also indicated that these measures appear to be influenced by other factors other than just gluteal muscle function, and therefore required investigation of their relevance to other clinical parameters of CLBP. A novel 2D photographic method of quantifying transverse plane body segment rotation of the pelvis was developed in Study 2 using a mechanical pelvic jig. Study 2 demonstrated that within a specific range of pelvic rotation, the novel 2D method could provide measurements of body segment rotation in the transverse plane that were within an acceptable range of error, if known concomitant motion in other planes and axes could be accounted for with the use of linear regression modeling. Study 3 further explored the validity and within-session reliability of this novel 2D method by comparing measurements of pelvic motion against those attained by a gold standard 3D method, in individuals with and without CLBP during movement control tests of the lumbo-pelvic-hip complex. Results showed that measurements derived from the 2D method demonstrated moderate to excellent agreement with 3D measures across the movement tasks. Average Root Mean Square Error was within acceptable limits, while Bland-Altman plots showed some individual variation, with at worst 95% limits of agreement less than ±6.2° across all measures and movement tasks. The capacity of the 2D method to detect differences in motion of the lumbo-pelvic-hip complex during motion control tests was evaluated in Study 4. This study demonstrated that individuals with unilateral CLBP consistently exhibit higher cumulative scores of multiplanar pelvis movement on the symptomatic side compared to healthy controls. Individuals with unilateral symptoms also displayed increased pelvic sagittal rotation during single-leg stance, and increased pelvic transverse rotation during single-leg squat and single-leg drop. Furthermore, some of the 2D method generated motion measurements demonstrated moderate to strong relationships with other clinical parameters (i.e. self- reported pain, disability, fear of movement) in the CLBP group. Study 4 also showed the 2 measures to have moderate to excellent between-session reliability during the motion control tests with Minimal Detectable Change ranging from 1.3° to 7.3°. This thesis has demonstrated the accuracy, reliability, and clinical relevance of a refined 2D method of measuring lumbo-pelvic-hip complex motion, including a novel approach to quantifying pelvic rotation in the transverse plane. Importantly from a measurement perspective this novel 2D method is of comparable accuracy to a gold standard 3D method. The 2D method is also capable of detecting potentially clinically relevant aberrant motion in those with CLBP. It is feasible that this relatively inexpensive 2D method may have valuable application in clinical settings in the future. 3 Declaration by author This thesis is composed of my original work, and contains no material previously published or written by another person except where due reference has been made in the text. I have clearly stated the contribution by others to jointly-authored works that I have included in my thesis. I have clearly stated the contribution of others to my thesis as a whole, including statistical assistance, survey design, data analysis, significant technical procedures, professional editorial advice, financial support and any other original research work used or reported in my thesis. The content of my thesis is the result of work I have carried out since the commencement of my higher degree by research candidature and does not include a substantial part of work that has been submitted to qualify for the award of any other degree or diploma in any university or other tertiary institution. I have clearly stated which parts of my thesis, if any, have been submitted to qualify for another award. I acknowledge that an electronic copy of my thesis must be lodged with the University Library and, subject to the policy and procedures of The University of Queensland, the thesis be made available for research and study in accordance with the Copyright Act 1968 unless a period of embargo has been approved by the Dean of the Graduate School. I acknowledge that copyright of all material contained in my thesis resides with the copyright holder(s) of that material. Where appropriate I have obtained copyright permission from the copyright holder to reproduce material in this thesis and have sought permission from co-authors for any jointly authored works included in the thesis. 4 Publications during candidature Conference abstracts Window, P.J., Culvenor, A.G., Michaleff, Z., Tucker, K., Hodges, P.W., O’Leary, S.P. (2015). Are clinical tests used to assess gluteal muscle function valid and reliable? a systematic review. Abstract accepted for oral presentation at APA Physiotherapy Conference, Gold Coast, October 2015. Window, P.J., McGrath, M., Grote, R., Tucker, K., Russell, T., Hodges, P.W., O’Leary, S.P. (2017). Accuracy of 2-dimensional measures of vertical axis rotation of the pelvis using photographic media: a comparison of two methods. Abstract accepted for oral presentation at XXVI Congress of the International Society of Biomechanics, Brisbane, July 2017. Window, P.J., McGrath, M., Hodges, P.W., Russell, T., Grote, R., Tucker, K., O’Leary, S.P. (2017). Agreement between 2D photographic and a gold standard 3D motion capture system in assessing pelvis motion in humans during movement tests of the lumbo-pelvic- hip complex. Abstract accepted for oral presentation at APA Physiotherapy Conference, Sydney, October 2017. 5 Publications included in this thesis No publications included. 6 Contributions by others to the thesis Substantial inputs were made by a number of individuals to the research, writing and editing reported in this thesis. - Dr Shaun O’Leary was pivotal in all aspects of the thesis including development