Margriet Van Dijk

Chapter 1: General introduction
Every day, people perform many different activities. The performance of activities involves a variety of movements and their interaction to the task, the environment and a person’s individual capabilities. Patients with low back pain adapt their movements due to the pain and to protect themselves from further pain or injury. If activities such as lifting, walking or cycling are (too) painful or problematic to perform or sustain, a person’s participation may be restricted. “I would like to be able to lift, walk and cycle again without pain in my lower back,” is therefore a common request for help from patients to primary care physio- and exercise therapists. To analyse and resolve patients’ needs for help, physio- and exercise therapists observe movement quality, the way HOW activities are performed. This observation may include an impression of whole-body movement, e.g., fluency, stride length, or focuses more local on body segments like, the position and rotation of the lumbar spine or hip extension when walking.

Despite the central role of observing and analysing movement quality in the process of clinical reasoning, a unified description of observable qualitative movement aspects are lacking. This hinders both an objective perception and evaluation and clear communication of movement quality. Valid and reliable assessment and responsive evaluation of movement quality are necessary to formulate a therapeutic diagnosis and treatment goals, to choose and adjust interventions and to understand treatment effectiveness. This thesis aims to provide primary care physio- and exercise therapists with a standardized observational assessment to describe and evaluate movement quality in patients with non-specific low back pain. To realize this aim, this thesis explores whether it is necessary and possible to select or develop a valid and reliable instrument to observe and measure movement quality in patients with non-specific low back pain for use by primary care physio- and exercise therapists?

Part I Inventory in clinical practice and literature
Chapter 2 presents the results of the first cross-sectional digital survey study. This study aimed at defining movement quality in patients with non-specific low back pain. For this study we invited primary care physio- and exercise therapists to articulate movement quality in open text descriptions. Additionally, the therapists were asked to select three movement quality keywords from their text. Due to the unclear and multi interpretable description and keywords of the 91 participating therapists we extended the intended exploratory qualitative content analysis with the application of the ICF linking rules (International Classification of Functioning, Disability and Health). The ICF linkage helps to reliably link the content of the descriptions and keywords to ICF codes. Then, the identified meaningful concepts (MCs) of the descriptions (274) and keywords (239) were linked to ICF codes of the ICF components: body functions and anatomical characteristics, activities and participation and to environmental (87.5% and 80.3%, respectively) and personal factors (5.8% and 5.9%, respectively), and supplementary codes (6.6% and 13.8%, respectively). The MCs were linked to a total of 31 ICF codes, especially to code b760 ‘control of voluntary movement functions’, b7602 ‘coordination of voluntary movements’, d4 ‘Mobility’, and d230 ‘carry out daily routine’. Moreover, negative and positive formulated descriptions expressed different movement quality interpretations, e.g., “Good posture alignment” or “Perform movements without hindrance”. We concluded that physio- and exercise therapists see movement quality as a multidimensional phenomenon encompassing all ICF components, including contextual factors, with coordination and functional movement seen as the most relevant concepts of movement quality. Because of the wide variety of both descriptions and therapists’ interpretation of movement quality, it proved too early for this inventory to define the construct.

Chapter 3 shows the results of the second cross-sectional digital survey study. In this study 114 physio- and exercise therapists described in open text how they observe movement quality during sitting down and getting up from a chair, lifting, dressing, and walking in patients with non-specific low back pain. Moreover, the therapists expressed if and how they assess movement quality. In addition, the therapists answered three closed questions about the clinical relevance of movement quality. Qualitative analyses of the answers to the open questions revealed four main themes that physio- and exercise therapists observe to get an impression of movement quality in patients with non-specific low back pain namely, 1) movement pattern features, 2) motor control features, 3) environmental influences, and 4) non-verbal expressions of pain and exertion. Quantitative analyses clearly indicated that physio- and exercise therapists implicitly observe movement quality in the diagnostic, therapeutic and evaluation phases. Moreover, the results show that 63% of the therapists consider it important to have a specific measurement instrument to assess movement quality in this population. Therapists critically noticed that such an assessment has both pros and cons for clinical reasoning and quality of care. We concluded that physiotherapists and exercise therapists subscribe to the importance of standardizing the observation of quality of movement during daily activities in patients with non-specific low back pain. However, consensus among therapists on standardizing observation is lacking. Prior to standardization, it will be important to determine which observable and measurable aspects of movement quality are most valid and relevant for patients with non-specific low back pain to include in the assessment. Prior to standardization, it is important to determine which observable and measurable aspects of quality of movement are most valid and relevant to describe and evaluate and in patients with nonspecific low back pain.

In Chapter 4 we performed a systematic review in three phases: 1) which movement domains are measured?; 2) which instruments are used?; and 3) which activities are relevant, appropriate and methodologically sound for assessing movement quality in patients with non-specific low back pain? Phase 1 and 2 of this systematic review revealed that the included 33 studies applied complex (n=19) and simple (n=7) instrumented motion analysis systems and standardized observational tests (n=7) to assess movement quality in patients with non-specific low back pain. Three identified domains representative for movement quality namely, range of motion (ROM), inter-segmental coordination, and whole-body movements significantly differentiated movement quality of healthy controls and patients with non-specific low back pain. Moreover, ROM and whole-body movements significantly improved over time in patients with non-specific low back pain. In phase 3 it appeared that none of the identified instruments was appropriate to assess movement quality in patients with non-specific low back pain in primary care setting of physio- and exercise therapy. We concluded that ROM, inter-segmental coordination and whole-body movements are relevant outcome to evaluate movement quality during forward bending, lifting, and walking. Since, this review as well as both inventories in clinical practice (chapters 2 and 3) showed that there are no suitable instruments available to measure movement quality in patients with non-specific low back pain, we recommended to develop such an instrument.

Conclusion Part I
Together, Chapters 2-4 demonstrate the clinical relevance, need and absence of a valid and reliable observational assessment of movement quality in patients with nonspecific low back pain, available to primary care physiotherapists and exercise therapists. Moreover, the results of Chapters 2-4 provided content for developing a standardised observational assessment of the movement quality of activities perceived as problematic by patients. To provide primary care physio- and exercise therapists with a standardized observational assessment it was decided to develop and validate such measurement instrument within this thesis.

Part II Development and testing of a standardized observational assessment of movement quality in patients with non-specific low back pain
To provide primary care physio- and exercise therapists with a standardized observational assessment the Observable Movement Quality scale for patients with LBP (OMQ-LBP) was developed (Chapter 5) and validated within this thesis (Chapter 6).

Chapter 5 illustrates how the results of Chapters 2-4 contribute for developing the OMQ-LBP. The OMQ-LBP aims to describe and evaluate movement quality of those daily activities reported by patients as problematic. The OMQ-LBP consists of a movement circuit with five activities and an 11-item observation list. Each item is defined and scored with a 5-point likert scale. Moreover, duration of the movement circuit is an additional outcome of the OMQ-LBP.

Chapter 6 describes the results of the extensive cross-sectional validation of the OMQ-LBP. This study addressed construct validity, internal consistency, inter- and intra-rater reliability, content validity, and the feasibility of the OMQ-LBP. In the absence of a gold standard, construct validity was determined by testing 11 a priori formulated hypotheses: two out of seven hypotheses confirmed correlations between observed movement quality and related but dissimilar constructs, and two out of four hypotheses confirmed known group differences. The confirmed hypotheses implied that: 1) movement quality in patients with low back pain is associated with movement speed and with perceived exertion during/after both circuits (n=85 patients), and 2) that patients have significantly lower OMQ-LBP scores compared to healthy controls (n=85 patients en n=63 healthy controls), and 3) that patients with more pain during/after the circuit take more time to perform the circuit (n=50 patients with VAS-pain < 20/100mm during after the movement circuit and n=35 patients having more pain (VAS-pain ≥ 20/100mm during/after both circuits) relative to 35 matched healthy controls (sex, age, BMI). Acceptable internal consistency (Cronbach’s α 0,79) was determined with 85 patients. To determine reliability 14 primary care therapists (seven physio- and seven exercise therapists) participated as observer. The therapists had no previous experience with the OMQ-LBP and were trained to learn to observe and score the 11 items from the video-recorded movement circuit. Moreover, the therapists were blinded to the status of selected patients (n=10) and healthy controls (n=2). The therapists achieved good intra-rater and moderate interrater reliability for the OMQ-LBP scores and excellent intra-rater and interrater reliability for the duration scores. Content validity was achieved by qualitative thematic analysis of a brief, structured interview with participating patients (n=38) and all participating therapists. Both, patients and therapists perceive the content of the OMQ-LBP as valid and the therapists indicate that the instrument has good practical applicability and adds value to the process of clinical reasoning. In addition, the therapists argue that the OMQ-LBP provides a clear and unambiguous language for movement quality in patients with low back pain. We concluded that the OMQ-LBP is promising for use in clinical practice and facilitates uniform communication with patients and colleagues. Since, a single study cannot fully validate a newly developed measurement instrument the validation research can be extended by examining associations with motor control tests, other blind observers, and subgroups of people with low back pain. Moreover, interrater reliability needs improvement and responsiveness and clinical relevance should be investigated. Conclusion Part II The newly developed OMQ-LBP allows first-line physiotherapists and exercise therapists to uniformly describe and evaluate observed movement quality in patients with low back pain. The objective description of movement quality adds value to clinical reasoning, facilitates unambiguous communication with patients and colleagues and enables comparison between patient-reported and observed outcomes in clinical practice. Following this exploratory development and validation of the OMQ-LBP, further validation and research on responsiveness is recommended. Chapter 7: General discussion Chapter 7 summarises the main findings of the studies from Chapter 2-6, provides a reflection on the results and their impact for clinical practice, education, and research and makes recommendations for these areas. Besides confirming the central role of observing movement quality within clinical reasoning of primary care physio- and exercise therapists, with the OMQ-LBP developed within this study, an objectified observation is now available that steps over therapists’ differing interpretations on perceived movement quality in patients with low back pain. We argue that standardized observation with the OMQ-LBP is a complementary assessment that adds clinical value to therapists’ bio-psycho-social approach when treating patients with both nonspecific and specific low back pain. Not least because the uniform description of observed movement quality ensures clear and positive communication with patients and colleagues. Based on the found need and ability to observe movement quality in a standardized way, and the currently established measurement properties, we consider the OMQ-LBP suitable for use in clinical practice. Given the early stage of development of the OMQ-LBP, further validation and investigation of responsiveness is required. Finally, to realize next steps that contribute to further development in clinical practice, education and scientific research, this thesis finishes with recommendations for each of these areas.