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  • 1. Conradsson, D.
    et al.
    Friden, C.
    Nilsson-Wikmar, L.
    Äng, Björn
    Ankle-joint mobility and standing squat posture in elite junior cross-country skiers. A pilot study2010In: Journal of Sports Medicine and Physical Fitness, ISSN 0022-4707, E-ISSN 1827-1928, Vol. 50, no 2, p. 132-8Article in journal (Refereed)
  • 2. de Alwis, M. P.
    et al.
    Lo Martire, R.
    Äng, Björn
    Garme, K.
    Development and validation of a web-based questionnaire for surveying the health and working conditions of high-performance marine craft populations2016In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 6, no 6, p. e011681-Article in journal (Refereed)
  • 3. de Alwis, M.P.
    et al.
    Garme, K:
    Martire, R. Lo
    Kåsin, J.I.
    Äng, Björn
    Dalarna University, School of Education, Health and Social Studies, Medical Science. Centre for Clinical Research Dalarna, Falun, Sweden; Division of Physiotherapy, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden.
    Crew acceleration exposure, health and performance in high-speed operations at sea2017Conference paper (Refereed)
    Abstract [en]

    The presented research program investigates the association between working conditions aboard High-Speed Craft (HSC) and its outcomes in terms of acceleration exposure and crew health and systems performance respectively. The aim is to identify the related risk factors and further, to use them to improve the assessment criteria in a simulation-based-design framework. The investigation initially document a seaborne population by a web-based questionnaire tailored for High-Performance Marine Craft Personnel (HPMCP) and similar populations. Then data is collected during regular service by measuring craft acceleration and through another questionnaire especially resolute on perceived work-exposure, health and performance. Exposure and performance data is collected daily and health data weekly, depending on seaborne frequency. The population repeats the prevalence questionnaire about a year later enabling a longitudinal follow-up for identifying long-term effects of exposure. The paper reports the two questionnaires´ development and pilot test as well as the first application for baseline data collection in the target group. The results indicate health and performance characteristics of the study population and data shows a promising correlation between the self-reported subjective exposure and the measured objective acceleration. Data indicates a comparatively higher prevalence of musculoskeletal pain in the study population than that of the general population.

  • 4. Gerdle, Björn
    et al.
    Åkerblom, Sophia
    Brodda Jansen, Gunilla
    Enthoven, Paul
    Ernberg, Malin
    Dong, Huan-Ji
    Stålnacke, Britt-Marie
    Äng, Björn
    Dalarna University, School of Education, Health and Social Studies, Medical Science. Karolinska institutet; Center for Clinical Research Dalarna.
    Boersma, Katja
    Who benefits from multimodal rehabilitation - an exploration of pain, psychological distress, and life impacts in over 35,000 chronic pain patients identified in the Swedish Quality Registry for Pain Rehabilitation2019In: Journal of Pain Research, ISSN 1178-7090, E-ISSN 1178-7090, Vol. 12, p. 891-908Article in journal (Refereed)
    Abstract [en]

    Background: Chronic pain patients frequently suffer from psychological symptoms. There is no consensus concerning the prevalence of severe anxiety and depressive symptoms and the strength of the associations between pain intensity and psychological distress. Although an important aspect of the clinical picture is understanding how the pain condition impacts life, little is known about the relative importance of pain and psychological symptoms for individual's life impact. The aims of this study were to identify subgroups of pain patients; to analyze if pain, psychological distress, and life impact variables influence subgrouping; and to investigate how patients in the subgroups benefit from treatments.

    Methods: Background variables, pain aspects (intensity/severity and spreading), psychological distress (depressive and anxiety symptoms), and two life impact variables (pain interference and perceived life control) were obtained from the Swedish Quality Registry for Pain Rehabilitation for chronic pain patients and analyzed mainly using advanced multivariate methods.

    Results: Based on >35,000 patients, 35%-40% had severe anxiety or depressive symptoms. Severe psychological distress was associated with being born outside Europe (21%-24% vs 6%-8% in the category without psychological distress) and low education level (20.7%-20.8% vs 26%-27% in the category without psychological distress). Dose relationships existed between the two psychological distress variables and pain aspects, but the explained variances were generally low. Pain intensity/severity and the two psychological distress variables were significantly associated (R2=0.40-0.48; P>0.001) with the two life impact variables (pain interference and life control). Two subgroups of patients were identified at baseline (subgroup 1: n=15,901-16,119; subgroup 2: n=20,690-20,981) and the subgroup with the worst situation regarding all variables participated less in an MMRP (51% vs 58%, P<0.001) but showed the largest improvements in outcomes.

    Conclusion: The results emphasize the need to assess both pain and psychological distress and not take for granted that pain involves high psychological stress in the individual case. Not all patients benefit from MMRP. A better matching between common clinical pictures and the content of MMRPs may help improve results. We only partly found support for treatment resistance in patients with psychological distress burden.

  • 5. Gerdle, Björn
    et al.
    Åkerblom, Sophia
    Stålnacke, Britt-Marie
    Brodda Jansen, Gunilla
    Enthoven, Paul
    Ernberg, Malin
    Dong, Huan-Ji
    Äng, Björn
    Dalarna University, School of Education, Health and Social Studies, Medical Science. Center for Clinical Research Dalarna; Karolinska institutet.
    Boersma, Katja
    The importance of emotional distress, cognitive behavioural factors and pain for life impact at baseline and for outcomes after rehabilitation - a SQRP study of more than 20,000 chronic pain patients2019In: Scandinavian Journal of Pain, ISSN 1877-8860, E-ISSN 1877-8879Article in journal (Refereed)
    Abstract [en]

    Background and aims Although literature concerning chronic pain patients indicates that cognitive behavioural variables, specifically acceptance and fear of movement/(re)injury, are related to life impact, the relative roles of these factors in relation to pain characteristics (e.g. intensity and spreading) and emotional distress are unclear. Moreover, how these variables affect rehabilitation outcomes in different subgroups is insufficiently understood. This study has two aims: (1) to investigate how pain, cognitive behavioural, and emotional distress variables intercorrelate and whether these variables can regress aspects of life impact and (2) to analyse whether these variables can be used to identify clinically meaningful subgroups at baseline and which subgroups benefit most from multimodal rehabilitation programs (MMRP) immediately after and at 12-month follow-up. Methods Pain aspects, background variables, psychological distress, cognitive behavioural variables, and two life impact variables were obtained from the Swedish Quality Registry for Pain Rehabilitation (SQRP) for chronic pain patients. These data were analysed mainly using advanced multivariate methods. Results The study includes 22,406 chronic pain patients. Many variables, including acceptance variables, showed important contributions to the variation in clinical presentations and in life impacts. Based on the statistically important variables considering the clinical presentation, three clusters/subgroups of patients were identified at baseline; from the worst clinical situation to the relatively good situation. These clusters showed significant differences in outcomes after participating in MMRP; the subgroup with the worst situation at baseline showed the most significant improvements. Conclusions Pain intensity/severity, emotional distress, acceptance, and life impacts were important for the clinical presentation and were used to identify three clusters with marked differences at baseline (i.e. before MMRP). Life impacts showed complex relationships with acceptance, pain intensity/severity, and emotional distress. The most significant improvements after MMRP were seen in the subgroup with the lowest level of functioning before treatment, indicating that patients with complex problems should be offered MMRP. Implications This study emphasizes the need to adopt a biopsychosocial perspective when assessing patients with chronic pain. Patients with chronic pain referred to specialist clinics are not homogenous in their clinical presentation. Instead we identified three distinct subgroups of patients. The outcomes of MMRP appears to be related to the clinical presentation. Thus, patients with the most severe clinical presentation show the most prominent improvements. However, even though this group of patients improve they still after MMRP show a complex situation and there is thus a need for optimizing the content of MMRP for these patients. The subgroup of patients with a relatively good situation with respect to pain, psychological distress, coping and life impact only showed minor improvements after MMRP. Hence, there is a need to develop other complex interventions for them.

  • 6. Gladh, K.
    et al.
    Lo Martire, R.
    Äng, Björn
    Lindholm, P.
    Nilsson, J.
    Westman, A.
    Decelerations of parachute opening shock in skydivers2017In: Aerospace Medicine and Human Performance, ISSN 2375-6314, Vol. 88, no 2, p. 121-127Article in journal (Refereed)
  • 7. Gladh, K.
    et al.
    Äng, Björn
    Lindholm, P.
    Nilsson, J.
    Westman, A.
    Decelerations and muscle responses during parachute opening shock2013In: Aviation, Space and Environmental Medicine, ISSN 0095-6562, E-ISSN 1943-4448, Vol. 84, no 11, p. 1205-10Article in journal (Refereed)
  • 8. Granström, Hannah
    et al.
    Äng, Björn
    Dalarna University, School of Education, Health and Social Studies, Sport and Health Science. Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Rasmussen-Barr, Eva
    Movement control tests for the lumbopelvic complex. Are these tests reliable and valid?2017In: Physiotherapy Theory and Practice, ISSN 0959-3985, E-ISSN 1532-5040, Vol. 33, no 5, p. 386-397Article in journal (Refereed)
    Abstract [en]

    This study evaluated inter- and intra-observer reliability and discriminative validity of three movement control tests: 1) standing knee-lift test; 2) static lunge test; and 3) dynamic lunge test. Thirty-eight subjects, 21 with low-back pain and 17 healthy, were video-recorded while performing the tests. Four physical therapists scored the tests according to a standardized protocol and calculated a composite score for each test based on the number of incorrect test components. Inter-observer reliability for the composite scores ranged between 0.68 and 0.80 (ICC 2,k) and intra-observer reliability between 0.54 and0.82 (ICC 2,1). The separate test components ranged between 0.32 and 0.91 (κfree) for inter-observer reliability and 0.42 and1.00 for intra-observer reliability. Test components showing the highest values were: back extension; arm lowering; and shoulders moving backwards. Components hip hitch, trunk lateral flexion, knee not lifted straight up and hips moving backwards did not reach accepted thresholds. Discriminative validity ranged between 0.47 and 0.56 (AUC). As our results showed an overall good agreement for the composite, scores and for the majority of the included test components the tests can be considered reliable enough. As the tests' discriminative ability was close to "none", they should, however, not be used for diagnostic purposes but should be further evaluated toward predicted validity.

  • 9. Grooten, W. J.
    et al.
    Conradsson, D.
    Äng, Björn
    Franzen, E.
    Is active sitting as active as we think?2013In: Ergonomics, ISSN 0014-0139, E-ISSN 1366-5847, Vol. 56, no 8, p. 1304-14Article in journal (Refereed)
  • 10. Grooten, W. J.
    et al.
    Äng, Björn
    Reliability of measurements of wrist extension force obtained with a Nicholas Manual Muscle Tester (NMMT)2010In: Physiotherapy Theory and Practice, ISSN 0959-3985, E-ISSN 1532-5040, Vol. 26, no 4, p. 281-7Article in journal (Refereed)
  • 11. Grooten, W.
    et al.
    Müller, M.
    Forsman, M.
    Kjellberg, K.
    Toomingas, A.
    Äng, Björn
    Dalarna University, School of Education, Health and Social Studies, Medical Science. Dalarna University, School of Education, Health and Social Studies, Sport and Health Science. Karolinska institutet.
    Svartengren, M.
    Health risk appraisals in Swedish occupational health services2016In: Work: A journal of Prevention, Assesment and rehabilitation, ISSN 1051-9815, E-ISSN 1875-9270, Vol. 55, no 4, p. 849-859Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Health risk appraisals (HRAs) in occupational health services (OHS) in Sweden are very commonly used for health promotion issues, but not much research has explored the extent and nature of individual feedback that is provided. 

    OBJECTIVES: This study aimed to describe and explore HRAs in OHS regarding the content of the feedback in relation to the individual status and overall employee satisfaction. 

    METHODS: Feedback (evaluation and advice) and employee satisfaction with HRA were studied in employees that participated in health risk appraisals with a specific feedback session (HRA-F) (n = 272) and employees that participated in a single session (HRA-S) (n = 104). Associations between feedback and individual status concerning life style were assessed with Cohen's kappa (k). 

    RESULTS: The employees received mainly information and advice for improvement on health and lifestyle issues (89-100%), while advice for improvement of working conditions was less common (15-59%). The feedback provided on life style was not based on individual status (k < 0.4), except for smoking and risky alcohol consumption (k > 0.55). A great majority of employees reported good overall satisfaction with their HRAs. 

    CONCLUSIONS: The evaluation and feedback given to employees after HRAs should be based more on HRA-results and advice could be focused more on work-related factors.

  • 12. Grooten, Wilhelmus Johannes Andreas
    et al.
    Hansson, Amanda
    Forsman, Mikael
    Kjellberg, Katarina
    Toomingas, Allan
    Müller, Mira
    Svartengren, Magnus
    Äng, Björn
    Dalarna University, School of Education, Health and Social Studies, Medical Science. Karolinska Institutet; Uppsala University.
    Non-participation in initial and repeated health risk appraisals: a drop-out analysis based on a health project2019In: BMC Health Services Research, ISSN 1472-6963, E-ISSN 1472-6963, Vol. 19, no 1, article id 130Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Health risk assessment (HRAs) are commonly used by occupational health services (OHS) to aid workplaces in keeping their employees healthy, but for unknown reasons, many employees choose not to participate in the HRAs. The aim of the study was to explore whether demographic, lifestyle and health-related factors in employees are associated with non-participation in initial and repeated HRAs.

    METHODS: In an OHS-based health project, 2022 municipal employees were asked to participate in three repeated HRAs. Multiple logistic regression analyses were used so as to determine associations between non-participating and demographic, lifestyle and health-related factors (e.g. biomarkers).

    RESULTS: Among the employees who were asked to participate in the health project, more than half did not participate in any HRA and among those who did, more than one third did not participate in repeated HRAs. Young age, male sex and being employed in the Technical department or Health and Social Care department in comparison with being employed in the department for Childcare and Education were factors significantly associated with non-participation in the initial HRA. These factors, together with being on sick leave and having unhealthy dietary habits, were factors associated with non-participation in repeated HRAs.

    CONCLUSIONS: Among the non-participators in initial HRAs and in repeated HRAs younger men and those already related to ill-health were overrepresented. This implicates that health care providers to a higher extent should focus on "those most needed" and that employers should be more engaged in results of repeated HRA's. Future studies should focus on modifiable variables that could make the HRAs more attractive and inclusive.

  • 13. Grooten, Wilhelmus Johannes Andreas
    et al.
    Tseli, Elena
    Äng, Björn
    Dalarna University, School of Education, Health and Social Studies, Medical Science. Karolinska institutet; Uppsala universitet.
    Boersma, Katja
    Stålnacke, Britt-Marie
    Gerdle, Björn
    Enthoven, Paul
    Elaborating on the assessment of the risk of bias in prognostic studies in pain rehabilitation using QUIPS-aspects of interrater agreement2019In: Diagnostic and Prognostic Research, ISSN 2397-7523, Vol. 3, article id 5Article in journal (Refereed)
    Abstract [en]

    Background: Many studies have been performed to identify important prognostic factors for outcomes after rehabilitation of patients with chronic pain, and there is a need to synthesize them through systematic review. In this process, it is important to assess the study quality and risk of bias. The "Quality In Prognosis Studies" (QUIPS) tool has been developed for this purpose and consists of several prompting items categorized into six domains, and each domain is judged on a three-grade scale (low, moderate or high risk of bias). The aim of the present study was to determine the interrater agreement of the risk of bias assessment in prognostic studies of patients with chronic pain using QUIPS and to elaborate on the use of this instrument.

    Methods: We performed a systematic review and a meta-analysis of prognostic factors for long-term outcomes after multidisciplinary rehabilitation in patients with chronic pain. Two researchers rated the risk of bias in 43 published papers in two rounds (15 and 28 papers, respectively). The interrater agreement and Cohen's quadratic weighted kappa coefficient (κ) and 95% confidence interval (95%CI) were calculated in all domains and separately for the first and second rounds.

    Results: The raters agreed in 61% of the domains (157 out of 258), with similar interrater agreement in the first (59%, 53/90) and second rounds (62%, 104/168). The overall weighted kappa coefficient (kappa for all domains and all papers) was weak: κ = 0.475 (95%CI = 0.358-0.601). A "minimal agreement" between the raters was found in the first round, κ = 0.323 (95%CI = 0.129-0.517), but increased to "weak agreement" in the second round, κ = 0.536 (95%CI = 0.390-0.682).

    Conclusion: Despite a relatively low interrater agreement, QUIPS proved to be a useful tool in assessing the risk of bias when performing a meta-analysis of prognostic studies in pain rehabilitation, since it demands of raters to discuss and investigate important aspects of study quality. Some items were particularly hard to differentiate in-between, and a learning phase was required to increase the interrater agreement. This paper highlights several aspects of the tool that should be kept in mind when rating the risk of bias in prognostic studies, and provides some suggestions on common pitfalls to avoid during this process.

    Trial registration: PROSPERO CRD42016025339; registered 05 February 2016.

  • 14. Grooten, W.J.A.
    et al.
    Äng, Björn
    Hagstromer, M.
    Conradsson, D.
    Nero, H.
    Franzen, E.
    Does a dynamic chair increase office workers' movements? – Results from a combined laboratory and field study2017In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 60, p. 1-11Article in journal (Refereed)
    Abstract [en]

    PURPOSE:

    Dynamic chairs have the potential to facilitate movements that could counteract health problems associated with sedentary office work. This study aimed to evaluate whether a dynamic chair can increase movements during desk-based office work.

    METHODS:

    Fifteen healthy subjects performed desk-based office work using a dynamic office chair and compared to three other conditions in a movement laboratory. In a field study, the dynamic office chair was studied during three working days using accelerometry.

    RESULTS:

    Equivocal results showed that the dynamic chair increased upper body and chair movements as compared to the conventional chair, but lesser movements were found compared to standing. No differences were found between the conditions in the field study.

    CONCLUSIONS:

    A dynamic chair may facilitate movements in static desk-based office tasks, but the results were not consistent for all outcome measures. Validation of measuring protocols for assessing movements during desk-based office work is warranted.

  • 15. Heijne, A.
    et al.
    Äng, Björn
    Werner, S.
    Predictive factors for 12-month outcome after anterior cruciate ligament reconstruction2009In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 19, no 6, p. 842-9Article in journal (Refereed)
  • 16. Kaping, K.
    et al.
    Äng, Björn
    Rasmussen-Barr, E.
    The abdominal drawing-in manoeuvre for detecting activity in the deep abdominal muscles: is this clinical tool reliable and valid?2015In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 5, no 12, p. e008711-Article in journal (Refereed)
  • 17. Lo Martire, R.
    et al.
    Gladh, K.
    Westman, A.
    Lindholm, P.
    Nilsson, J.
    Äng, Björn
    Neck muscle activity in skydivers during parachute opening shock2016In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 26, no 3, p. 307-16Article in journal (Refereed)
  • 18. Lo Martire, Riccardo
    et al.
    de Alwis, Manudul Pahansen
    Äng, Björn
    Dalarna University, School of Education, Health and Social Studies, Medical Science. Karolinska institutet.
    Garme, Karl
    Construction of a web-based questionnaire for longitudinal investigation of work exposure, musculoskeletal pain and performance impairments in high-performance marine craft populations2017In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 7, no 7, article id e016006Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: High-performance marine craft personnel (HPMCP) are regularly exposed to vibration and repeated shock (VRS) levels exceeding maximum limitations stated by international legislation. Whereas such exposure reportedly is detrimental to health and performance, the epidemiological data necessary to link these adverse effects causally to VRS are not available in the scientific literature, and no suitable tools for acquiring such data exist. This study therefore constructed a questionnaire for longitudinal investigations in HPMCP.

    METHODS: A consensus panel defined content domains, identified relevant items and outlined a questionnaire. The relevance and simplicity of the questionnaire's content were then systematically assessed by expert raters in three consecutive stages, each followed by revisions. An item-level content validity index (I-CVI) was computed as the proportion of experts rating an item as relevant and simple, and a scale-level content validity index (S-CVI/Ave) as the average I-CVI across items. The thresholds for acceptable content validity were 0.78 and 0.90, respectively. Finally, a dynamic web version of the questionnaire was constructed and pilot tested over a 1-month period during a marine exercise in a study population sample of eight subjects, while accelerometers simultaneously quantified VRS exposure.

    RESULTS: Content domains were defined as work exposure, musculoskeletal pain and human performance, and items were selected to reflect these constructs. Ratings from nine experts yielded S-CVI/Ave of 0.97 and 1.00 for relevance and simplicity, respectively, and the pilot test suggested that responses were sensitive to change in acceleration and that the questionnaire, following some adjustments, was feasible for its intended purpose.

    CONCLUSIONS: A dynamic web-based questionnaire for longitudinal survey of key variables in HPMCP was constructed. Expert ratings supported that the questionnaire content is relevant, simple and sufficiently comprehensive, and the pilot test suggested that the questionnaire is feasible for longitudinal measurements in the study population.

  • 19. Lo Martire, Riccardo
    et al.
    Gladh, Kristofer
    Westman, Anton
    Äng, Björn
    Dalarna University, School of Education, Health and Social Studies, Sport and Health Science. Karolinska Institutet.
    Neck muscle EMG-force relationship and its reliability during isometric contractions2017In: Sports medicine - open, ISSN 2199-1170, Vol. 3, no 1, article id 16Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Susceptible to injury, the neck is subject to scientific investigations, frequently aiming to elucidate possible injury mechanisms via surface electromyography (EMG) by indirectly estimating cervical loads. Accurate estimation requires that the EMG-force relationship is known and that its measurement error is quantified. Hence, this study examined the relationship between EMG and isometric force amplitude of the anterior neck (AN), the upper posterior neck (UPN), and the lower posterior neck (LPN) and then assessed the relationships' test-retest reliability across force-percentiles within and between days.

    METHODS: EMG and force data were sampled from 18 participants conducting randomly ordered muscle contractions at 5-90% of maximal voluntary force during three trials over 2 days. EMG-force relationships were modeled with general linear mixed-effects regression. Overall fitted lines' between-trial discrepancies were evaluated. Finally, the reliability of participants' fitted regression lines was quantified by an intraclass correlation coefficient (ICC) and the standard error of measurement (SEM).

    RESULTS: A rectilinear model had the best fit for AN while positively oriented quadratic models had the best fit for UPN and LPN, with mean adjusted conditional coefficients of determination and root mean square errors of 0.97-0.98 and 4-5%, respectively. Overall EMG-force relationships displayed a maximum 6% between-trial discrepancy and over 20% of maximal force, and mean ICC was above 0.79 within day and 0.27-0.61 between days across areas. Corresponding SEM was below 12% both within and between days across areas, excluding UPN between days, for which SEM was higher.

    CONCLUSIONS: EMG-force relationships were elucidated for three neck areas, and provided models allow inferences to be drawn from EMG to force on a group level. Reliability of EMG-force relationship models was higher within than between days, but typically acceptable for all but the lowest contraction intensities, and enables adjustment for measurement imprecision in future studies.

  • 20. Molander, P.
    et al.
    Dong, H. -J
    Äng, Björn
    Dalarna University, School of Education, Health and Social Studies, Medical Science. Karolinska institutet.
    Enthoven, P.
    Gerdle, B.
    The role of pain in chronic pain patients' perception of health-related quality of life: A cross-sectional SQRP study of 40,000 patients2018In: Scandinavian Journal of Pain, ISSN 1877-8860, E-ISSN 1877-8879, Vol. 18, no 3Article in journal (Refereed)
    Abstract [en]

    Health-related quality of life (Hr-QoL) reflects the burden of a condition on an overarching level. Pain intensity, disability and other factors influence how patients with chronic pain perceive their condition, e.g. Hr-QoL. However, the relative importance of these factors is unclear and there is an ongoing debate as to what importance pain measures have in this group. We investigated the importance of current pain level and mood on aspects of Hr-QoL in patients with chronic pain and investigated whether such relationships are influenced by demographics. Data was obtained from the Swedish Quality Registry for Pain Rehabilitation (SQRP), between 2008 and 2016 on patients ≥18 years old who suffered from chronic pain and were referred to participating specialist clinics. Dependent variables were general Hr-QoL [using two scales from European Quality of Life instrument: EQ5D Index and the European Quality of Life instrument health scale (EQ thermometer)] and specific Hr-QoL [from the Short Form Health Survey (SF36) the physical component summary (SF36-PCS) and the mental (psychological) component summary (SF36-MCS)]. Independent variables were sociodemographic variables, pain variables, psychological distress and pain attitudes. Principal component analysis (PCA) was used for multivariate correlation analyses of all investigated variables and Orthogonal Partial Least Square Regression (OPLS) for multivariate regressions on health aspects. There was 40,518 patients (72% women). Pain intensity and interference showed the strongest multivariate correlations with EQ5D Index, EQ thermometer and SF36-PCS. Psychological distress variables displayed the strongest multivariate correlations with SF36-MCS. Demographic properties did not significantly influence variations in the investigated Hr-QoL variables. Pain, mood and pain attitudes were significantly correlated with Hr-QoL variables, but these variables cannot explain most of variations in Hr-QoL variables. The results pinpoint that broad assessments (including pain intensity aspects) are needed to capture the clinical presentation of patients with complex chronic pain conditions.

  • 21. Monnier, A.
    et al.
    Djupsjobacka, M.
    Larsson, H.
    Norman, K.
    Äng, Björn
    Risk factors for back pain in marines; a prospective cohort study2016In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 17, p. 319-Article in journal (Refereed)
  • 22. Monnier, A.
    et al.
    Heuer, J.
    Norman, K.
    Äng, Björn
    Inter- and intra-observer reliability of clinical movement-control tests for marines2012In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 13, p. 263-Article in journal (Refereed)
  • 23. Monnier, A.
    et al.
    Larsson, H.
    Djupsjobacka, M.
    Brodin, L. A.
    Äng, Björn
    Musculoskeletal pain and limitations in work ability in Swedish marines: a cross-sectional survey of prevalence and associated factors2015In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 5, no 10, p. e007943-Article in journal (Refereed)
  • 24. Monnier, Andreas
    et al.
    Larsson, Helena
    Nero, Håkan
    Djupsjöbacka, Mats
    Äng, Björn
    Dalarna University, School of Education, Health and Social Studies, Medical Science. Karolinska institutet; Uppsala universitet.
    A longitudinal observational study of back pain incidence, risk factors and occupational physical activity in Swedish marine trainees2019In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 9, no 5, article id e025150Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: To evaluate the occurrence of low back pain (LBP) and LBP that limits work ability, to identify their potential early risks and to quantify occupational physical activity in Swedish Armed Forces (SwAF) marines during their basic 4 month marine training course.

    DESIGN: Prospective observational cohort study with weekly follow-ups.

    PARTICIPANTS: Fifty-three SwAF marines entering the training course.

    OUTCOMES: Incident of LBP and its related effect on work-ability and associated early risks. Occupational physical activity, as monitored using accelerometers and self-reports.

    RESULTS: During the training course, 68% of the marines experienced at least one episode of LBP. This yielded a LBP and LBP limiting work ability incidence rate of 13.5 (95% CI 10.4 to 17.8) and 6.3 (95% CI 4.2 to 10.0) episodes per 1000 person-days, respectively. Previous back pain and shorter body height (≤1.80 m) emerged as independent risks for LBP (HR 2.5, 95% CI 1.4 to 4.3; HR 2.0, 95% CI 1.2 to 3.3, respectively), as well as for LBP that limited work ability (HR 3.6, 95% CI 1.4 to 8.9; HR 4.5, 95% CI 2.0 to 10.0, respectively). Furthermore, managing fewer than four pull-ups emerged as a risk for LBP (HR 1.9, 95% CI 1.2 to 3.0), while physical training of fewer than three sessions per week emerged as a risk for LBP that limited work ability (HR 3.0, 95% CI 1.2 to 7.4). More than 80% of the work time measured was spent performing low levels of ambulation, however, combat equipment (≥17.5 kg) was carried for more than half of the work time.

    CONCLUSIONS: Incidents of LBP are common in SwAF marines' early careers. The link between LBP and previous pain as well as low levels of exercise highlights the need for preventive actions early on in a marine's career. The role of body height on LBP needs further investigation, including its relationship with body-worn equipment, before it can effectively contribute to LBP prevention.

  • 25. Nilsson, J.
    et al.
    Friden, C.
    Buren, V.
    Westman, A.
    Lindholm, P.
    Äng, Björn
    Musculoskeletal pain and related risks in skydivers: a population-based survey2013In: Aviation, Space and Environmental Medicine, ISSN 0095-6562, E-ISSN 1943-4448, Vol. 84, no 10, p. 1034-40Article in journal (Refereed)
  • 26. Nilsson, J.
    et al.
    Friden, C.
    Buren, V.
    Äng, Björn
    Development and validation of a web-based questionnaire for surveying skydivers2011In: Aviation, Space and Environmental Medicine, ISSN 0095-6562, E-ISSN 1943-4448, Vol. 82, no 6, p. 610-4Article in journal (Refereed)
  • 27. Posch, Markus
    et al.
    Schranz, Alois
    Lener, Manfred
    Senn, Werner
    Äng, Björn
    Dalarna University, School of Education, Health and Social Studies, Medical Science. Karolinska institutet.
    Burtscher, Martin
    Ruedl, Gerhard
    Prevalence and potential risk factors of flight-related neck, shoulder and low back pain among helicopter pilots and crewmembers: a questionnaire-based study2019In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 20, no 1, article id 44Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Flight-related neck, shoulder and low back pain are the most common musculoskeletal disorders among helicopter pilots and their crewmembers, thus becoming a growing concern. Information on the combined prevalence of these types of pain and related risks are scarce. The aim of this study was therefore to estimate pain prevalence and to evaluate potential risk factors for neck pain among helicopter pilots and crewmembers within the armed forces, the airborne police and airborne rescue organizations in Austria.

    METHODS: Among a cohort of 104 helicopter pilots and 117 crewmembers (69.8% compliance), demographics, flying experience, use of Night Vision Goggles (NVG), helicopter type flown, prevalence and intensity of musculoskeletal symptoms (pain was defined as any reported pain experience, ache or discomfort) were collected by an online-based questionnaire.

    RESULTS: For helicopter pilots the 12-month prevalence of neck pain was 67.3%, followed by low back (48.1%) and shoulder pain (43.3%). Among crewmembers, the 12-month pain prevalence were 45.3, 36.8 and 30.8% among the neck, lower back and shoulder, respectively. During this period, 41.8% of these helicopter pilots had experienced 8-30 pain days in the areas of neck (45.7%), shoulder (37.8%) and lower back (42.0%) whereas 47.8% of crewmembers self-reported 1-7 days of neck (54.7%), low back (44.2%) and shoulder (44.4%) pain in the previous year. The 3-month prevalence of neck pain was 64.4% followed by low back (42.3%) and shoulder pain (38.5%) for helicopter pilots. Among crewmembers, 41.9% suffered from neck, 29.9% from low back and 29.1% from shoulder pain the previous 3 months. Multivariate regression analysis revealed NVG use (OR 1.9, 95% CI, 1.06-3.50, p = 0.032), shoulder pain (OR 4.9, 95% CI, 2.48-9.55, p < 0.001) and low back pain (OR 2.3, 95% CI, 1.21-4.31, p = 0.011) to be significantly associated with neck pain.

    CONCLUSIONS: The 12- and 3-month prevalence of neck, shoulder and low back is considerably high among both, helicopter pilots and crewmembers confirming the existence of this growing concern. The use of NVG devices, shoulder and low back pain in the previous 12 months represent independent risk factors for neck pain. These findings highlight the need for longitudinal studies.

  • 28. Pousette, M. W.
    et al.
    Lo Martire, R.
    Linder, J.
    Kristoffersson, M.
    Äng, Björn
    Neck Muscle Strain in Air Force Pilots Wearing Night Vision Goggles2016In: Aerospace Medicine and Human Performance, ISSN 2375-6322, Vol. 87, no 11, p. 928-932Article in journal (Refereed)
  • 29. Rasmussen-Barr, E.
    et al.
    Campello, M.
    Arvidsson, I.
    Nilsson-Wikmar, L.
    Äng, Björn
    Factors predicting clinical outcome 12 and 36 months after an exercise intervention for recurrent low-back pain2012In: Disability and Rehabilitation, ISSN 0963-8288, E-ISSN 1464-5165, Vol. 34, no 2, p. 136-44Article in journal (Refereed)
  • 30. Rasmussen-Barr, E.
    et al.
    Granstrom, H.
    Äng, Björn
    Inter- and intra-observer reliability of three movement control tests for the lumbo-pelvic complex2015In: Physiotherapy, ISSN 0031-9406, E-ISSN 1873-1465, Vol. 101, no suppl. 1, p. e1259-e1260Article in journal (Refereed)
  • 31. Rasmussen-Barr, E.
    et al.
    Äng, Björn
    Arvidsson, I.
    Nilsson-Wikmar, L.
    Graded exercise for recurrent low-back pain: a randomized, controlled trial with 6-, 12-, and 36-month follow-ups2009In: Spine, ISSN 0362-2436, E-ISSN 1528-1159, Vol. 34, no 3, p. 221-8Article in journal (Refereed)
  • 32. Soderberg, J.
    et al.
    Grooten, W. J.
    Äng, Björn
    Effects of eccentric training on hand strength in subjects with lateral epicondylalgia: a randomized-controlled trial2012In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 22, no 6, p. 797-803Article in journal (Refereed)
  • 33. Tegern, Matthias
    et al.
    Aasa, Ulrika
    Äng, Björn
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Harms-Ringdahl, Karin
    Larsson, Helena
    Inter-rater and test-retest reliability of movement control tests for the neck, shoulder, thoracic, lumbar, and hip regions in military personnel2018In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 13, no 9, article id e0204552Article in journal (Refereed)
    Abstract [en]

    Strategies are needed to mitigate the high rates and related risks of musculoskeletal complaints and injuries (MSCI) in the military aviator community. Previous work on Swedish Armed Forces (SwAF) soldiers have shown that proper screening methods have been successful in reducing early discharge from military training. Research has pointed at the importance of optimal spinal movement control in military aviators. The aim of this work was to investigate the inter-rater and test-retest reliability of a battery of clinical tests for evaluating movement control in the neck, shoulders, thoracic, lumbar, and hip regions in a population of SwAF military personnel. Inter-rater and test-retest reliability of 15 movement control tests were assessed by crude and prevalence-adjusted kappa coefficient. The study included 37 (inter-rater) and 45 (test-retest) SwAF personnel and was performed with two physiotherapists simultaneously observing and rating the movements on the first occasion and repeated with one physiotherapist on the second occasion. For inter-rater reliability, the kappa coefficient ranged from .19 to .95. Seven tests showed substantial to almost perfect agreement (kappa > .60). With the adjusted kappa, three more tests reached the level of substantial agreement. The corresponding values for test-retest reliability ranged from .26 to .65. Substantial agreement was attained for two tests, three with adjusted kappa. The following tests can reliably be used when screening for biomechanically less advantageous movement patters in military aviators: Shoulder flexion, and rotation, Neck flexion in sitting and supine, Neck extension and rotation in sitting, Pelvic tilt, Forward lean and Single and Double knee extension tests. Grading criteria for tests in supine and quadruped positions need to be further elaborated.

  • 34. Thuresson, M.
    et al.
    Äng, Björn
    Linder, J.
    Harms-Ringdahl, K.
    Intra-rater reliability of electromyographic recordings and subjective evaluation of neck muscle fatigue among helicopter pilots2005In: Journal of Electromyography & Kinesiology, ISSN 1050-6411, E-ISSN 1873-5711, Vol. 15, no 3, p. 323-31Article in journal (Refereed)
  • 35. Thuresson, M.
    et al.
    Äng, Björn
    Linder, J.
    Harms-Ringdahl, K.
    Mechanical load and EMG activity in the neck induced by different head-worn equipment and neck postures2005In: International Journal of Industrial Ergonomics, ISSN 0169-8141, E-ISSN 1872-8219, Vol. 35, no 1, p. 13-18Article in journal (Refereed)
  • 36. Thuresson, M.
    et al.
    Äng, Björn
    Linder, J.
    Harms-Ringdahl, K.
    Neck muscle activity in helicopter pilots: effect of position and helmet-mounted equipment2003In: Aviation, Space and Environmental Medicine, ISSN 0095-6562, E-ISSN 1943-4448, Vol. 74, no 5, p. 527-32Article in journal (Refereed)
  • 37. Torstensen, Tom Arild
    et al.
    Grooten, Wilhelmus J A
    Østerås, Håvard
    Heijne, Annette
    Harms-Ringdahl, Karin
    Äng, Björn
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    How does exercise dose affect patients with long-term osteoarthritis of the knee? A study protocol of a randomised controlled trial in Sweden and Norway: the SWENOR Study2018In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 8, no 5, article id e018471Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: Osteoarthritis (OA) of the knee is characterised by knee pain, disability and degenerative changes, and places a burden on societies all over the world. Exercise therapy is an often-used modality, but there is little evidence of what type of exercise dose is the most effective, indicating a need for controlled studies of the effect of different dosages. Thus, the aim of the study described in this protocol is to evaluate the effects of high-dose versus low-dose medical exercise therapy (MET) in patients with knee OA.

    METHODS AND ANALYSIS: This is a multicentre prospective randomised two-arm trial with blinded assessment and data analysis. We are planning to include 200 patients aged 45-85 years with symptomatic (pain and decreased functioning) and X-ray verified diagnosis of knee OA. Those eligible for participation will be randomly allocated to either high-dose (n=100) or low-dose (n=100) MET. All patients receive three supervised treatments each week for 12 weeks, giving a total of 36 MET sessions. The high-dose group exercises for 70-90 min compared with 20-30 min for the low-dose group. The high-dose group exercises for a longer time, and receives a greater number of exercises with more repetitions and sets. Background and outcome variables are recorded at inclusion, and outcome measures are collected after every sixth treatment, at the end of treatment, and at 6-month and 12-month follow-ups. Primary outcome is self-rated knee functioning and pain using the Knee Injury and Osteoarthritis Outcome Score (KOOS). The primary end point is at the end of treatment after 3 months, and secondary end points are at 6 months and 12 months after the end of treatment.

    ETHICS AND DISSEMINATION: This project has been approved by the Regional Research Ethics Committees in Stockholm, Sweden, and in Norway. Our results will be submitted to peer-reviewed journals and presented at national and international conferences.

    TRIAL REGISTRATION NUMBER: NCT02024126; Pre-results.

  • 38. Tsaklis, P.
    et al.
    Karlsson, J.
    Grooten, W. J.
    Äng, Björn
    A combined sensorimotor skill and strength training programme improves postural steadiness in rhythmic sports athletes2008In: Human Movement, ISSN 1732-3991, E-ISSN 1899-1955, Vol. 9, no 1, p. 34-40Article in journal (Refereed)
  • 39. Tseli, Elena
    et al.
    Grooten, Wilhelmus Johannes Andreas
    Stålnacke, Britt-Marie
    Boersma, Katja
    Enthoven, Paul
    Gerdle, Björn
    Äng, Björn
    Dalarna University, School of Education, Health and Social Studies, Medical Science. Karolinska institutet.
    Predictors of multidisciplinary rehabilitation outcomes in patients with chronic musculoskeletal pain: protocol for a systematic review and meta-analysis2017In: Systematic Reviews, E-ISSN 2046-4053, ISSN 2046-4053, Vol. 6, no 1, article id 199Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Chronic musculoskeletal pain is a major public health problem. Early prediction for optimal treatment results has received growing attention, but there is presently a lack of evidence regarding what information such proactive management should be based on. This study protocol, therefore, presents our planned systematic review and meta-analysis on important predictive factors for health and work-related outcomes following multidisciplinary rehabilitation (MDR) in patients with chronic musculoskeletal pain.

    METHODS: We aim to perform a synthesis of the available evidence together with a meta-analysis of published peer-reviewed original research that includes predictive factors preceding MDR. Included are prospective studies of adults with benign, chronic (> 3 months) musculoskeletal pain diagnoses who have taken part in MDR. In the studies, associations between personal and rehabilitation-based factors and the outcomes of interest are reported. Outcome domains are pain, physical functioning including health-related quality of life, and work ability with follow-ups of 6 months or more. We will use a broad, explorative approach to any presented predictive factors (demographic, symptoms-related, physical, psychosocial, work-related, and MDR-related) and these will be analyzed through (a) narrative synthesis for each outcome domain and (b) if sufficient studies are available, a quantitative synthesis in which variance-weighted pooled proportions will be computed using a random effects model for each outcome domain. The strength of the evidence will be evaluated using the Grading of Recommendations, Assessment, Development and Evaluation.

    DISCUSSION: The strength of this systematic review is that it aims for a meta-analysis of prospective cohort or randomized controlled studies by performing an extensive search of multiple databases, using an explorative study approach to predictive factors, rather than building on single predictor impact on the outcome or on predefined hypotheses. In this way, an overview of factors central to MDR outcome can be made and will help strengthen the evidence base and inform a wide readership including health care practitioners and policymakers.

    SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42016025339.

  • 40. Tseli, Elena
    et al.
    Stålnacke, Britt-Marie
    Boersma, Katja
    Enthoven, Paul
    Gerdle, Björn
    Äng, Björn
    Dalarna University, School of Education, Health and Social Studies, Medical Science. Karolinska institutet; Center for Clinical Research Dalarna.
    Grooten, Wilhelmus Johannes Andreas
    Prognostic factors for physical functioning after multidisciplinary rehabilitation in patients with chronic musculoskeletal pain: a systematic review and meta-analysis2019In: The Clinical Journal of Pain, ISSN 0749-8047, E-ISSN 1536-5409, Vol. 35, no 2, p. 148-173Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: This systematic review aimed to identify and evaluate prognostic factors for long-term (≥6▒mo) physical functioning in patients with chronic musculoskeletal pain following multidisciplinary rehabilitation (MDR).

    METHODS: Electronic searches conducted in MEDLINE, PsycINFO, EMBASE, CINAHL, Web of Science, and Cochrane CENTRAL revealed 25 original research reports, published 1983-2016, (n=9436). Potential prognostic factors relating to initial pain and physical and psychological functioning were synthesized qualitatively and quantitatively in random effects meta-analyses. The level of evidence (LoE) was evaluated with GRADE.

    RESULTS: Pain related factors (intensity and chronicity) were not associated with function/disability at long-term follow up, OR=0.84, 95% CI: 0.65-1.07 and OR=0.97, 95% CI: 0.93-1.00 respectively (moderate LoE). A better function at follow up was predicted by Physical factors; higher levels of initial self-reported functioning, OR=1.07, 95% CI: 1.02-1.13 (low LoE), and Psychological factors; low initial levels of emotional distress, OR=0.77, 95% CI: 0.65-0.92, low levels of cognitive behavioural risk factors, OR 0.85, 95% CI: 0.77-0.93 and high levels of protective cognitive behavioural factors, OR=1.49; 95% CI: 1.17-1.90 (moderate LoE).

    DISCUSSION: While pain intensity and long-term chronicity did not predict physical functioning in chronic pain patients after MDR, poor pre-treatment physical and psychological functioning influenced the prognosis negatively. Thus, treatment should further target and optimize these modifiable factors and an increased focus on positive, psychological protective factors may perhaps provide an opening for yet untapped clinical gains.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0/.

  • 41. Westman, A.
    et al.
    Äng, Björn
    Free Fall Acrobatics to Reduce Neck Loads During Parachute Opening Shock: Evaluation of an Intervention (ACROPOSE)2016In: BMJ Open Sport & Exercise Medicine, ISSN 2055-7647, Vol. 2, no 1, p. e000108-Article in journal (Refereed)
  • 42. Westman, A.
    et al.
    Äng, Björn
    Validation of a free fall acrobatics intervention protocol to reduce neck loads during parachute opening shock2015In: BMJ Open Sport & Exercise Medicine, ISSN 2055-7647, Vol. 1, no 1Article in journal (Refereed)
  • 43. Äng, Björn
    Impaired neck motor function and pronounced pain-related fear in helicopter pilots with neck pain - a clinical approach2008In: Journal of Electromyography & Kinesiology, ISSN 1050-6411, E-ISSN 1873-5711, Vol. 18, no 4, p. 538-49Article in journal (Refereed)
  • 44. Äng, Björn
    et al.
    Harms-Ringdahl, K.
    Neck pain and related disability in helicopter pilots: A survey of prevalence and risk factors2006In: Aviation, Space and Environmental Medicine, ISSN 0095-6562, E-ISSN 1943-4448, Vol. 77, no 7, p. 713-9Article in journal (Refereed)
  • 45. Äng, Björn
    et al.
    Kristoffersson, M.
    Neck muscle activity in fighter pilots wearing night-vision equipment during simulated flight2013In: Aviation, Space and Environmental Medicine, ISSN 0095-6562, E-ISSN 1943-4448, Vol. 84, no 2, p. 125-33Article in journal (Refereed)
  • 46. Äng, Björn
    et al.
    Linder, J.
    Harms-Ringdahl, K.
    Neck strength and myoelectric fatigue in fighter and helicopter pilots with a history of neck pain2005In: Aviation, Space and Environmental Medicine, ISSN 0095-6562, E-ISSN 1943-4448, Vol. 76, no 4, p. 375-80Article in journal (Refereed)
  • 47. Äng, Björn
    et al.
    Monnier, A.
    Harms-Ringdahl, K.
    Neck/shoulder exercise for neck pain in air force helicopter pilots: a randomized controlled trial2009In: Spine, ISSN 0362-2436, E-ISSN 1528-1159, Vol. 34, no 16, p. E544-51Article in journal (Refereed)
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