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  • 1.
    Aasa, Ulrika
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Bengtsson, Victor
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Berglund, Lars
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Sports Medicine.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Variability of lumbar spinal alignment among power- and weightlifters during the deadlift and barbell back squat2022In: Sports Biomechanics, ISSN 1476-3141, E-ISSN 1752-6116, Vol. 21, no 6, p. 707-717Article in journal (Refereed)
    Abstract [en]

    The aims of the study were to evaluate the relative and absolute variability of upper (T11-L2) and lower (L2-S2) lumbar spinal alignment in power- and weightlifters during the deadlift and back squat exercises, and to compare this alignment between the two lifting groups. Twenty-four competitive powerlifters (n = 14) and weightlifters (n = 10) performed three repetitions of the deadlift and the back squat exercises using a load equivalent to 70% of their respective one-repetition maximum. The main outcome measures were the three-dimensional lumbar spinal alignment for start position, minimum and maximum angle of their spinal alignment, and range of motion measured using inertial measurement units. Relative intra-trial reliability was calculated using the two-way random model intraclass correlation coefficient (ICC) and absolute reliability with minimal detectable change (MDC). The ICC ranged between 0.69 and 0.99 and the MDC between 1 degrees-8 degrees for the deadlift. Corresponding figures for the squat were 0.78-0.99 and 1 degrees-6 degrees. In all participants during both exercises, spinal adjustments were made in both thoracolumbar and lumbopelvic areas in all three dimensions. In conclusion, when performing three repetitions of the deadlift and the squat, lumbar spinal alignment of the lifters did not change much between repetitions and did not differ significantly between power- and weightlifters.

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  • 2.
    Bengtsson, Victor
    et al.
    Department of Neuroscience, Uppsala University, Sweden.
    Aasa, Ulrika
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Berglund, Lars
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation.
    Thoracolumbar and lumbopelvic spinal alignment during the deadlift exercise: a comparison between men and women2022In: International Journal of Sports Physical Therapy, E-ISSN 2159-2896, Vol. 17, no 6, p. 1063-1074Article in journal (Refereed)
    Abstract [en]

    Background: A neutral spinal alignment is considered important during the execution of the deadlift exercise to decrease the risk of injury. Since male and female powerlifters experience pain in different parts of their backs, it is important to examine whether men and women differ in spinal alignment during the deadlift.

    Objectives: The purpose of this study was to quantify the spinal alignment in the upper (thoracolumbar, T11-L2) and lower (lumbopelvic, L2-S2) lumbar spine during the deadlift exercise in male and female lifters. Secondary aims were to compare lumbar spine alignment during the deadlift to standing habitual posture, and determine whether male and female lifters differ in these aspects.

    Study Design: Observational, Cross-sectional.

    Methods: Twenty-four (14 men, 10 women) lifters performed three repetitions of the deadlift exercise using 70% of their respective one-repetition maximum. Spinal alignment and spinal range of motion were measured using three inertial measurement units placed on the thoracic, lumbar and sacral spine. Data from three different positions were analyzed; habitual posture in standing, and start and stop positions of the deadlift, i.e. bottom and finish position respectively.

    Results: During the deadlift, spinal adjustments were evident in all three planes of movement. From standing habitual posture to the start position the lumbar lordosis decreased 13° in the upper and 20° in the lower lumbar spine. From start position to stop position the total range of motion in the sagittal plane was 11° in the upper and 22° in the lower lumbar spine. The decreased lumbar lordosis from standing habitual posture to the start position was significantly greater among men.

    Conclusions: Men and women adjust their spinal alignment in all three planes of movement when performing a deadlift and men seem to make greater adjustments from their standing habitual posture to start position in the sagittal plane. Level of Evidence 3.

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  • 3.
    Bengtsson, Victor
    et al.
    Department of Women's and Children's Health, Uppsala university.
    Berglund, Lars
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Aasa, Ulrika
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Thoracolumbar and Lumbopelvic Spinal Alignment During the Barbell Back Squat: A Comparison Between Men and Women2023In: International Journal of Sports Physical Therapy, E-ISSN 2159-2896, Vol. 18, no 4, p. 820-830Article in journal (Refereed)
    Abstract [en]

    Background:  Maintaining neutral spinal alignment is considered important when performing the barbell back squat exercise. Since male and female lifters may differ in injury location it is important to examine whether they differ in spinal alignment during the back squat.

    Objectives:  The study aimed to quantify the spinal alignment in the upper and lower lumbar spine during the barbell back squat exercise in male and female lifters. Secondary aims were to compare alignment during the back squat to standing habitual lumbar spine alignment and determine whether male and female lifters differ in these aspects.

    Study design:  Observational, Cross-sectional.

    Methods:  Competitive power- and weightlifters were recruited and performed three repetitions of the barbell back squat exercise using a load equivalent to 70% of their one-repetition maximum. Spinal alignment and range of motion were measured using inertial measurement units placed on the thoracic, lumbar and sacral spine. Data was presented descriptively and comparisons between men and women as well as spinal alignment in four different positions were done with a factorial repeated measures analysis of variance.

    Results:  Twenty-three (14 males, 9 females) were included. During execution of the squat, spinal alignment adjustments in the lumbar spine were made in all three planes of movement, compared to the start position, in both male and female lifters. Compared to their standing habitual posture, all lifters adjusted their upper lumbar spine to a less lordotic position when in the start position of the back squat (standing upright with the barbell on their back). Only male lifters assumed a less lordotic alignment in their lower lumbar spine in the start position compared their habitual posture.

    Conclusions:  Adjustments of spinal alignment, predominantly in the sagittal plane, are made during execution of the back squat in both male and female lifters. Further, lifters adopt a less lordotic alignment with a heavy barbell on their upper back, more so in male than female lifters. In conclusion, it seems that spinal alignment changes noticeably during the barbell back squat.

    Level of evidence:  3

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  • 4.
    Bergman, Frida
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Matsson-Frost, Tove
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Jonasson, Lars S.
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Chorell, Elin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Sörlin, Ann
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation.
    Wennberg, Patrik
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Ryberg, Mats
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Levine, James A
    Mayo Clinic Rochester MN, USA; Fondation IPSEN, Paris, France.
    Olsson, Tommy
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Boraxbekk, Carl-Johan
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Danish Research Center for Magnetic Resonance (DRCMR), Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Hvidovre, Denmark; Institute of Sports Medicine Copenhagen (ISMC), Copenhagen University Hospital, Copenhagen, Denmark.
    Walking Time Is associated With Hippocampal Volume in Overweight and Obese Office Workers2020In: Frontiers in Human Neuroscience, E-ISSN 1662-5161, Vol. 14, article id 307Article in journal (Refereed)
    Abstract [en]

    Objectives: To investigate the long-term effects on cognition and brain function after installing treadmill workstations in offices for 13 months.

    Methods: Eighty healthy overweight or obese office workers aged 40–67 years were individually randomized to an intervention group, receiving a treadmill workstation and encouraging emails, or to a control group, continuing to work as usual. Effects on cognitive function, hippocampal volume, prefrontal cortex (PFC) thickness, and circulating brain-derived neurotrophic factor (BDNF) were analyzed. Further, mediation analyses between changes in walking time and light-intensity physical activity (LPA) on changes in BDNF and hippocampal volume between baseline and 13 months, and multivariate analyses of the baseline data with percentage sitting time as the response variable, were performed.

    Results: No group by time interactions were observed for any of the outcomes. In the mediation analyses, positive associations between changes in walking time and LPA on changes in hippocampal volume were observed, although not mediated by changes in BDNF levels. In the multivariate analyses, a negative association between percentage sitting time and hippocampal volume was observed, however only among those older than 51 years of age.

    Conclusion: Although no group by time interactions were observed, our analyses suggest that increased walking and LPA may have positive effects on hippocampal volume and that sedentary behavior is associated with brain structures of importance for memory functions.

    Trial Registration: www.ClinicalTrials.gov as NCT01997970.

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  • 5.
    Bergman, Frida
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Mattson-Frost, Tove
    Jonasson, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Chorell, Elin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Sörlin, Ann
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Wennberg, Patrik
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Ryberg, Mats
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Levine, James
    Olsson, Tommy
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Boraxbekk, Carl-Johan
    Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR).
    Installing treadmill workstations in offices does little for cognitive performance and brain structure, despite a baseline association between sitting time and hippocampus volumeManuscript (preprint) (Other academic)
  • 6.
    Bergman, Frida
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Wahlström, Viktoria
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Stomby, Andreas
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Otten, Julia
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lanthén, Ellen
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Renklint, Rebecka
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Waling, Maria
    Umeå University, Faculty of Social Sciences, Department of Food and Nutrition.
    Sörlin, Ann
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Boraxbekk, Carl-Johan
    Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR). Danish Research Center for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Hvidovre, Denmark.
    Wennberg, Patrik
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Levine, James A.
    Department of Endocrinology, The Mayo Clinic, Rochester, MN, USA; Fondation IPSEN, Paris, France.
    Olsson, Tommy
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Treadmill workstations in office workers who are overweight or obese: a randomised controlled trial2018In: The Lancet Public Health, ISSN 2468-2667, Vol. 3, no 11, article id e523-e535Article in journal (Refereed)
    Abstract [en]

    Background: Treadmill workstations that enable office workers to walk on a treadmill while working at their computers might increase physical activity in offices, but long-term effects are unknown. We therefore investigated whether treadmill workstations in offices increased daily walking time.

    Methods: We did a randomised controlled trial of healthy office workers who were either overweight or obese. We recruited participants from 13 different companies, which comprised 17 offices, in Umeå, Sweden. We included people who were aged 40-67 years, had sedentary work tasks, and had a body-mass index (BMI) between 25 kg/m2 and 40 kg/m2. After the baseline measurement, we stratified participants by their BMI (25-30 kg/m2 and >30 to 40 kg/m2); subsequently, an external statistician randomly assigned these participants (1:1) to either the intervention group (who received treadmill workstations for optional use) or the control group (who continued to work at their sit-stand desks as usual). Participants in the intervention group received reminders in boosting emails sent out to them at four occasions during the study period. Researchers were masked to group assignment until after analysis of the primary outcome. After the baseline measurement, participants were not masked to group belongings. The primary outcome was total daily walking time at weekdays and weekends, measured at baseline, 2 months, 6 months, 10 months, and 13 months with the accelerometer activPAL (PAL Technologies, Glasgow, UK), which was worn on the thigh of participants for 24 h a day for 7 consecutive days. We used an intention-to-treat approach for our analyses. This trial is registered with ClinicalTrials.gov, number NCT01997970, and is closed to new participants.

    Findings: Between Nov 1, 2013, and June 30, 2014, a total of 80 participants were recruited and enrolled (n=40 in both the intervention and control groups). Daily walking time during total time awake at weekdays increased between baseline and 13 months by 18 min (95% CI 9 to 26) in the intervention group and 1 min (-7 to 9) in the control group (difference 22 min [95% CI 7 to 37], pinteraction=0·00045); for weekend walking, the change from baseline to 13 months was 5 min (-8 to 18) in the intervention group and 8 min (-5 to 21) in the control group (difference -1 min [-19 to 17]; pinteraction=0·00045). Neither measure met our predetermined primary outcome of 30 min difference in total walking time between the intervention and control group, so the primary outcome of the trial was not met. One adverse event was reported in a participant who accidently stepped on their Achilles tendon.

    Interpretation: In a sedentary work environment, treadmill workstations result in a statistically significant but smaller-than-expected increase in daily walking time. Future studies need to investigate how increasing physical activity at work might have potentially compensatory effects on non-work activity.

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  • 7.
    Bergman, Frida
    et al.
    Umeå University.
    Wahlström, Viktoria
    Umeå University.
    Wennberg, Patrik
    Umeå University.
    Boraxbekk, Carl-Johan
    Umeå University.
    Sörlin, Ann
    Umeå University.
    Öhberg, Fredrik
    Umeå University.
    Olsson, Tommy
    Umeå University.
    Increasing Physical Activity In Office Workers - An RCT Of Treadmill Workstations2018In: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 50, no 5, p. 47-47Article in journal (Other academic)
    Abstract [en]

    PURPOSE: Our primary hypothesis was that an intervention with treadmill workstations would increase time spent walking. Secondary hypotheses were a decrease in time spent sitting with a concomitant increase in time spent standing and in light intensity physical activity (LPA) leading to positive effects on body measurements and body composition.

    METHODS: The intervention group received a treadmill workstation at their office desk during 13 months. Daily time spent sitting, standing and walking and number of steps was measured with activPAL®. Daily time in LPA and MVPA was measured with Actigraph®. Body weight, BMI and waist circumference were measured according to standardized protocols. Dual X-ray Absorptiometry was used to estimate body composition. Mixed models was used for the statistical analysis, with group, day of week (weekday/ weekend), time point and gender as fixed effects and age as a covariate. p<0.05 was considered significant.

    RESULTS: Eighty participants were included. The intervention group significantly increased their time spent walking at all follow-ups, with a difference at 13 months of 22 minutes (p<0.01) and 1645 steps per day (p<0.05), respectively, versus controls. Concomitantly, they decreased their MVPA with 13 minutes per day (p<0.001) at weekdays at 13 months versus baseline. We also found a decrease in LPA with 19 minutes per day (p<0.05), and of 17 minutes per day for MVPA (p<0.001) at 13 months versus baseline at weekends. The control group increased their time spent sitting with 25 minutes per day (p<0.05) and decreased the time spent standing with 35 minutes per day at weekdays (p<0.001) compared to baseline. There was also a decrease in LPA with 14 minutes per day (p<0.01) and in MVPA with 6 minutes per day (p<0.01) versus baseline during weekdays, with a decrease in sitting time with 36 minutes (p<0.05) at weekends. There were no significant changes in body measurements or body composition.

    CONCLUSION: It is possible to increase daily walking time by introducing treadmill workstations at offices. A decreased MVPA within the intervention group may contribute to lack of effects on body measurements and body composition. It is therefore important that future interventions aim at both reducing sedentary time as well as increasing, or at least remaining, MVPA levels.

  • 8.
    Bjerke, Joakim
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy. Department of Physiotherapy, School of Health Education & Social Work, Sør-Trøndelag University College, Trondheim, Norway.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Nilsson, Kjell G
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Foss, Olav A
    Orthopaedic Research Centre, Trondheim University Hospital, Trondheim, Norway.
    Stensdotter, Ann-Katrin
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy. Department of Physiotherapy, School of Health Education & Social Work, Sør-Trøndelag University College, Trondheim, Norway.
    Peak knee flexion angles during stair descent in TKA patients2014In: The Journal of Arthroplasty, ISSN 0883-5403, E-ISSN 1532-8406, Vol. 29, no 4, p. 707-711Article in journal (Refereed)
    Abstract [en]

    Reduced peak knee flexion during stair descent (PKSD) is demonstrated in subjects with total knee arthroplasty (TKA), but the underlying factors are not well studied. 3D gait patterns during stair descent, peak passive knee flexion (PPKF), quadriceps strength, pain, proprioception, demographics, and anthropometrics were assessed in 23 unilateral TKA-subjects ~ 19 months post-operatively, and in 23 controls. PKSD, PPKF and quadriceps strength were reduced in the TKA-side, but also in the contralateral side. A multiple regression analysis identified PPKF as the only predictor (57%) to explain the relationship with PKSD. PPKF was, however sufficient for normal PKSD. Deficits in quadriceps strength in TKA-group suggest that strength is also contributing to smaller PKSD. Increased hip adduction at PKSD may indicate both compensatory strategy and reduced hip strength.

  • 9.
    Bjerke, Joakim
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy. Department of Physiotherapy, School of Health Education & Social Work, Sør-Trøndelag University College, Trondheim, Norway.
    Öhberg, Fredrik
    Department of Biomedical Engineering & Informatics, Umeå University Hospital, Umeå, Sweden.
    Nilsson, Kjell G
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Stensdotter, Ann-Katrin
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy. Department of Physiotherapy, School of Health Education & Social Work, Sør-Trøndelag University College, Trondheim, Norway.
    Compensatory strategies for muscle weakness during stair ascent in subjects with total knee arthroplasty2014In: The Journal of Arthroplasty, ISSN 0883-5403, E-ISSN 1532-8406, Vol. 29, no 7, p. 1499-1502Article in journal (Refereed)
    Abstract [en]

    Subjects with total knee arthroplasty (TKA) exhibit decreased quadriceps and hamstring strength. This may bring about greater relative effort or compensatory strategies to reduce knee joint moments in daily activities. To study gait and map out the resource capacity, knee muscle strength was assessed by maximal voluntary concentric contractions, and whole body kinematics and root mean square (RMS) electromyography (EMG) of vastus lateralis and semitendinosus were recorded during stair ascent in 23 unilateral TKA-subjects ~19months post-operation, and in 23 healthy controls. Muscle strength and gait velocity were lower in the TKA group, but no significant group differences were found in RMS EMG or forward trunk lean. The results suggest that reduced walking velocity sufficiently compensated for reduced knee muscle strength.

  • 10.
    Bjerke, Joakim
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy. Department of Physiotherapy, School of Health Education & Social Work, Sør-Trøndelag University College, Trondheim, Norway.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Nilsson, Kjell G
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Stensdotter, Ann-Katrin
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy. Department of Physiotherapy, School of Health Education & Social Work, Sør-Trøndelag University College, Trondheim, Norway.
    Gait on soft versus hard surface after total knee arthroplastyManuscript (preprint) (Other academic)
    Abstract [en]

    Asymmetric gait patterns are common following total knee arthroplasty (TKA). Gait on even and hard surface is primarily characterized by reduced peak knee flexion in the prosthetic knee, increased contralateral knee adduction angle, and decreased walking speed compared to controls. Natural conditions may however lead to different strategies. Therefore, the objective of the present study was to explore how gait patterns may differ when walking on a soft surface. Methods: 3D kinematics during gait on hard and soft surface were assessed in 23 unilateral TKA-subjects ~19 months post-operative, and in 23 controls. Results: Gait characteristics in TKA-subjects that differed from controls observed on hard surface were amplified on soft surface. Flexion in the prosthetic knee was further decreased and a tendency towards reduced flexion in the contralateral knee was observed. Knee and hip adduction were not affected by surface conditions nevertheless there was a difference between groups, in particular with regard to the prosthetic side. In addition, step width increased on soft surface in TKA-subjects. Conclusion: Gait on an even and soft surface did not amplify asymmetries in TKA-subjects, but decreased knee flexion and increased step-width, albeit with similar gait speed as the control group suggests that the soft surface provided a small but significant challenge making the TKA-subjects precautious.

  • 11.
    Bjerke, Joakim
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy. Department of Physiotherapy, Faculty of Health and Social Sciences, Norwegian University of Science and Technology, Trondheim, Norway.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Nilsson, Kjell G
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Stensdotter, Ann-Katrin
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation. epartment of Physiotherapy, Faculty of Health and Social Sciences, Norwegian University of Science and Technology, Trondheim, Norway .
    Walking on a compliant surface does not enhance kinematic gait asymmetries after unilateral total knee arthroplasty2016In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 24, no 8, p. 2606-2613Article in journal (Refereed)
    Abstract [en]

    PURPOSE: To investigate gait asymmetries and the effect of walking on compliant surfaces in individuals with unilateral total knee arthroplasty (TKA), hypothesizing that asymmetries would increase as an effect of the compliant surface.

    METHODS: Individuals with unilateral TKA ~19 months post-operative (n = 23, median age 59 years) recruited from one orthopaedic clinic and age- and gender-matched healthy individuals without knee complaints (n = 23, median age 56 years) walked at comfortable speed on a hard surface and on a compliant surface. 3D kinematic analyses were made for knee and hip angles in sagittal and frontal planes, stance time, step length, and gait velocity.

    RESULTS: Shorter stance time (p < 0.01) and less peak knee flexion (p < 0.001) at weight bearing acceptance was found in the prosthetic side compared with the contralateral side. Larger knee (p < 0.01) and hip (p < 0.001) adduction was found compared with healthy controls. Neither asymmetries between the prosthetic and the contralateral side nor differences compared with healthy controls were enhanced when walking on compliant surfaces compared with hard surfaces.

    CONCLUSION: The TKA group adapted their gait to compliant surfaces similarly to healthy controls. Gait asymmetries in the TKA group observed on hard surface were not enhanced, and adduction in hip and knee joints did not increase further as an effect of walking on compliant surfaces. Thus, unfavourable knee joint loading did not increase when walking on a compliant surface. This implies that recommendations for walking on soft surfaces to reduce knee joint loading are not counteracted by increased gait asymmetries and unfavourable joint loading configurations.

    LEVEL OF EVIDENCE: III.

  • 12.
    Bäcklund, Tomas
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Grip, Helena
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Sundström, Nina
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Single sensor measurement of heel-height during the push-off phase of gait2021In: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, Vol. 42, no 10, article id 105016Article in journal (Refereed)
    Abstract [en]

    Objective: In healthy gait a forceful push-off is needed to get an efficient leg swing and propulsion, and a high heel lift makes a forceful push-off possible. The power of the push-off is decreased with increased age and in persons with impaired balance and gait. The aim of this study was to evaluate whether a wearable equipment (Striton) and algorithms to estimate vertical heel-height during gait from a single optical distance sensor is reliable and feasible for clinical applications.

    Approach: To assess heel-height with the Striton system an optical distance sensor was used to measure the distance to the floor along the shank. An algorithm was created to transform this measure to a vertical distance. The heel-height was validated in an experimental setup, against a 3D motion capture system (MCS), and test-retest and day-to-day tests were performed on 10 elderly persons. As a reference material 83 elderly persons were included, and heel-height was measured before and after surgery in four patients with the neurological disorder idiopathic normal pressure hydrocephalus (iNPH).

    Main results: In the experimental setup the accuracy was high with a maximum error of 2% at all distances, target colours and inclination angles, and the correlation to the MCS was R = 0.94. Test-retest and day-to-day tests were equal within ±1.2 cm. Mean heel-height of the elderly persons was 16.5 ± 0.6 cm and in the patients with iNPH heel-height was increased from 11.2 cm at baseline to 15.3 cm after surgery.

    Significance: Striton can reliably measure heel-height during gait, with low test-retest and day-to-day variability. The system was easy to attach, and simple to use, which makes it suitable for clinical applications.

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  • 13.
    Bäcklund, Tomas
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Grip, Helena
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Johansson, Gudrun
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation.
    Sundström, Nina
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    O 035 - A novel method to measure step width during the swing phase of gait2018In: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, Vol. 65, p. 71-72Article in journal (Refereed)
  • 14.
    Bäcklund, Tomas
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Johansson, Gudrun
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation.
    Grip, Helena
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Sundström, Nina
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Novel, clinically applicable method to measure step-width during the swing phase of gait2020In: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, Vol. 41, no 6, article id 065005Article in journal (Refereed)
    Abstract [en]

    Objective: Step-width during walking is an indicator of stability and balance in patients with neurological disorders, and development of objective tools to measure this clinically would be a great advantage. The aim of this study was to validate an in-house-developed gait analysis system (Striton), based on optical and inertial sensors and a novel method for stride detection, for measuring step-width during the swing phase of gait and temporal parameters.

    Approach: The step-width and stride-time measurements were validated in an experimental setup, against a 3D motion capture system and on an instrumented walkway. Further, test-retest and day-to-day variability were evaluated, and gait parameters were collected from 87 elderly persons (EP) and four individuals with idiopathic normal pressure hydrocephalus (iNPH) before/after surgery.

    Main results: Accuracy of the step-width measurement was high: in the experimental setup mean error was 0.08 +/- 0.25 cm (R = 1.00) and against the 3D motion capture system 0.04 +/- 1.12 cm (R = 0.98). Test-retest and day-to-day measurements were equal within +/- 0.5 cm. Mean difference in stride time was -0.003 +/- 0.008 s between Striton and the instrumented walkway. The Striton system was successfully applied in the clinical setting on individuals with iNPH, which had larger step-width (6.88 cm, n = 4) compared to EP (5.22 cm, n = 87).

    Significance: We conclude that Striton is a valid, reliable and wearable system for quantitative assessment of step-width and temporal parameters during gait. Initial measurements indicate that the newly defined step-width parameter differs between EP and patients with iNPH and before/after surgery. Thus, there is potential for clinical applicability in patients with reduced gait stability.

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  • 15.
    Dahlgren, Gunilla
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Liv, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Slunga-Järvholm, Lisbeth
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Forsman, Mikael
    IMM Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden; Division of Ergonomics, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Hälsovägen 11C, Huddinge, Sweden.
    Rehn, Börje
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Correlations between Ratings and Technical Measurements in Hand-Intensive Work2023In: Bioengineering, E-ISSN 2306-5354, Vol. 10, no 7, article id 867Article in journal (Refereed)
    Abstract [en]

    An accurate rating of hand activity and force is essential in risk assessment and for the effective prevention of work-related musculoskeletal disorders. However, it is unclear whether the subjective ratings of workers and observers correlate to corresponding objective technical measures of exposure. Fifty-nine workers were video recorded while performing a hand-intensive work task at their workplace. Self-ratings of hand activity level (HAL) and force (Borg CR10) using the Hand Activity Threshold Limit Value® were assessed. Four ergonomist observers, in two pairs, also rated the hand activity and force level for each worker from video recordings. Wrist angular velocity was measured using inertial movement units. Muscle activity in the forearm muscles flexor carpi radialis (FCR) and extensor carpi radialis (ECR) was measured with electromyography root mean square values (RMS) and normalized to maximal voluntary electrical activation (MVE). Kendall’s tau-b correlations were statistically significant between self-rated hand activity and wrist angular velocity at the 10th, 50th, and 90th percentiles (0.26, 0.31, and 0.23) and for the ratings of observers (0.32, 0.41, and 0.34). Significant correlations for force measures were found only for observer-ratings in five of eight measures (FCR 50th percentile 0.29, time > 10%MVE 0.43, time > 30%MVE 0.44, time < 5% −0.47) and ECR (time > 30%MVE 0.26). The higher magnitude of correlation for observer-ratings suggests that they may be preferred to the self-ratings of workers. When possible, objective technical measures of wrist angular velocity and muscle activity should be preferred to subjective ratings when assessing risks of work-related musculoskeletal disorders.

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  • 16.
    Dahlgren, Gunilla
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Liv, Per
    Umeå University, Faculty of Medicine, Department of Epidemiology and Global Health. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Slunga-Järvholm, Lisbeth
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Forsman, Mikael
    IMM Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden; Division of Ergonomics, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Hälsovägen 11C, Huddinge, Sweden.
    Rehn, Börje
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Ratings of hand activity and force levels among women and men who perform identical hand-intensive work tasks2022In: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 19, no 24, article id 16706Article in journal (Refereed)
    Abstract [en]

    We compared hand activity and force ratings in women and men doing identical hand-intensive work tasks. Musculoskeletal disorders are more common in women and hand-intensive work leads to an increased risk of these disorders. Knowledge of the gender influence in the rating of work exposure is lacking. The aim of this study was to investigate whether women and men performing identical hand-intensive work tasks were equally rated using hand activity and normalized peak force levels with the Hand Activity Threshold Limit Value®. Fifty-six workers participated, comprising 28 women-men pairs. Four observers-two woman-man pairs-were also involved. Self-ratings and observers' ratings of hand activity and force level were collected. The results of these ratings showed no significant gender differences in self-rated hand activity and force, as well as observer-rated hand activity. However, there was a significant gender difference in the observer-rated force, where the women were rated higher (mean (SD): women 3.9 (2.7), men 3.1 (1.8) (p = 0.01)). This difference remained significant in the adjusted model (p = 0.04) with grip strength and forearm-finger anthropometrics. The results provide new insights that observers' estimates of force can be higher in women compared with men in the same work tasks. Force should be further investigated and preferably compared to objective measurements.

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  • 17. Ertzgaard, Per
    et al.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Gerdle, Björn
    Grip, Helena
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    A new way of assessing arm function in activity using kinematic Exposure Variation Analysis and portable inertial sensors - A validity study2016In: Manual Therapy, ISSN 1356-689X, E-ISSN 1532-2769, Vol. 21, p. 241-249Article in journal (Refereed)
    Abstract [en]

    Portable motion systems based on inertial motion sensors are promising methods, with the advantage compared to optoelectronic cameras of not being confined to a laboratory setting. A challenge is to develop relevant outcome measures for clinical use. The aim of this study was to characterize elbow and shoulder motion during functional tasks, using portable motion sensors and a modified Exposure Variation Analysis (EVA) and evaluate system accuracy with optoelectronic cameras. Ten healthy volunteers and one participant with sequel after stroke performed standardised functional arm tasks. Motion was registered simultaneously with a custom developed motion sensor system, including gyroscopes and accelerometers, and an optoelectronic camera system. The EVA was applied on elbow and shoulder joints, and angular and angular velocity EVA plots was calculated. The EVA showed characteristic patterns for each arm task in the healthy controls and a distinct difference between the affected and unaffected arm in the participant with sequel after stroke. The accuracy of the portable system was high with a systematic error ranging between -1.2 degrees and 2.0 degrees. The error was direction specific due to a drift component along the gravity vector. Portable motion sensor systems have high potential as clinical tools for evaluation of arm function. EVA effectively illustrates joint angle and joint angle velocity patterns that may capture deficiencies in arm function and movement quality. Next step will be to manage system drift by including magnetometers, to further develop clinically relevant outcome variables and apply this for relevant patient groups.

  • 18.
    Fredrik, Öhberg
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Grip, Helena
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Nilsson, Kjell G
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Edström, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Gustavsson, Ola
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Häger, Charlotte
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Gait analysis using a portable motion sensor system: measurements in subjects with hip implant as compared with healthy controls2013In: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, Vol. 38, no suppl 1, p. 99-100Article in journal (Refereed)
    Abstract [en]

    Introduction: There is an increase of age related diseases such as hip joint arthritis, something that is often treated with hip replacement surgery. The aim of this study was to quantify movement function and its effect on quality of life in persons treated with hip implant, in comparison to matched asymptomatic controls.

    Patients/Materials and Methods: This is an ongoing study, and so far, 2 asymptomatic subjects (CTRL, age 50 ± 13 years, BMI 23 ± 2), and 4 subjects with hip implant (HIP, age 51 ± 15 years, BMI 25 ± 3), have been analyzed. The HIP group received their implant 2.6 ± 1.1 years ago and finished their rehabilitation 1.6 ± 1.1 years ago. Hip dysfunction and Osteoarthritis Outcome Score (HOOS) was used to assess the subject's hip function and its associated problems. A functional calibration (flexion/abduction movements) was done and each subject then performed 5 repetitions of gait (approx. 25 left/right gait cycles). Movement was registered with a custom-developed portable motion sensor system, where each sensor consisted of a tri-axial accelerometer and gyroscope. Sensors were placed on pelvis and each thigh and shank. Further calculations were done in MATLAB (v7.12 R2011a, Mathworks). Cosine rotation matrices were extracted by functional sensor-to- segment-calibration and sensor fusion [1], and hip and knee angles were obtained as Euler angles.

    Results: Preliminary results indicated larger range in hip rotation and smaller range of knee flexion during gait in HIP group than in the CTRL group (Fig. 1). HOOS profile (Fig. 2) indicated that hip function during sports (SP) and the general quality of life (QOL) were lower in the HIP group.

    Fig. 1. 

    Mean and SD of hip and knee angle over 15 gait cycles in one HIP subject (blue) as compared with the CTRL group (black). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

    Figure optionsFig. 2. 

    HOOS profiles in HIP (blue square) and CTRL group (black). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

    Figure options

    Discussion and conclusions: Motion patterns during gait seemed to be negatively affected in subjects with hip implant, even after the rehabilitation program was completed and even though the HOOS profiles indicated a relative good hip function.

    Reference

    • [1]
    • J. Favre, B.M. Jolles, O. Siegrist, K. Aminian
    • Quaternion-based fusion of gyroscopes and accelerometers to improve 3D angle measurement

  • 19.
    Grip, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Källströmer, Anna
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Validity and reliability of wearable motion sensors for clinical assessment of shoulder function in brachial plexus birth injury2022In: Sensors, E-ISSN 1424-8220, Vol. 22, no 23, article id 9557Article in journal (Refereed)
    Abstract [en]

    The modified Mallet scale (MMS) is commonly used to grade shoulder function in brachial plexus birth injury (BPBI) but has limited sensitivity and cannot grade scapulothoracic and glenohumeral mobility. This study aims to evaluate if the addition of a wearable inertial movement unit (IMU) system could improve clinical assessment based on MMS. The system validity was analyzed with simultaneous measurements with the IMU system and an optical camera system in three asymptomatic individuals. Test–retest and interrater reliability were analyzed in nine asymptomatic individuals and six BPBI patients. IMUs were placed on the upper arm, forearm, scapula, and thorax. Peak angles, range of motion, and average joint angular speed in the shoulder, scapulothoracic, glenohumeral, and elbow joints were analyzed during mobility assessments and MMS tasks. In the validity tests, clusters of reflective markers were placed on the sensors. The validity was high with an error standard deviation below 3.6°. Intraclass correlation coefficients showed that 90.3% of the 69 outcome scores showed good-to-excellent test–retest reliability, and 41% of the scores gave significant differences between BPBI patients and controls with good-to-excellent test–retest reliability. The interrater reliability was moderate to excellent, implying that standardization is important if the patient is followed-up longitudinally.

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  • 20.
    Grip, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Nilsson, Kjell G
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Häger, Charlotte G.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Does the Femoral Head Size in Hip Arthroplasty Influence Lower Body Movements during Squats, Gait and Stair Walking?: A Clinical Pilot Study Based on Wearable Motion Sensors2019In: Sensors, E-ISSN 1424-8220, Vol. 19, no 14, article id 3240Article in journal (Refereed)
    Abstract [en]

    A hip prosthesis design with larger femoral head size may improve functional outcomes compared to the conventional total hip arthroplasty (THA) design. Our aim was to compare the range of motion (RoM) in lower body joints during squats, gait and stair walking using a wearable movement analysis system based on inertial measurement units (IMUs) in three age-matched male groups: 6 males with a conventional THA (THAC), 9 with a large femoral head (LFH) design, and 8 hip- and knee-asymptomatic controls (CTRL). We hypothesized that the LFH design would allow a greater hip RoM, providing movement patterns more like CTRL, and a larger side difference in hip RoM in THAC when compared to LFH and controls. IMUs were attached to the pelvis, thighs and shanks during five trials of squats, gait, and stair ascending/descending performed at self-selected speed. THAC and LFH participants completed the Hip dysfunction and Osteoarthritis Outcome Score (HOOS). The results showed a larger hip RoM during squats in LFH compared to THAC. Side differences in LFH and THAC groups (operated vs. non-operated side) indicated that movement function was not fully recovered in either group, further corroborated by non-maximal mean HOOS scores (LFH: 83 +/- 13, THAC: 84 +/- 19 groups, vs. normal function 100). The IMU system may have the potential to enhance clinical movement evaluations as an adjunct to clinical scales.

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  • 21.
    Grip, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Sterner, Ylva
    Karlsson, J Stefan
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Gerdle, Björn
    Classification of neck movement patterns related to whiplash-associated disorders using neural networks2003In: IEEE transactions on information technology in biomedicine, ISSN 1089-7771, Vol. 7, no 4, p. 412-418Article in journal (Refereed)
    Abstract [en]

    This paper presents a new method for classification of neck movement patterns related to Whiplash-associated disorders (WAD) using a resilient backpropagation neural network (BPNN). WAD are a common diagnosis after neck trauma, typically caused by rear-end car accidents. Since physical injuries seldom are found with present imaging techniques, the diagnosis can be difficult to make. The active range of the neck is often visually inspected in patients with neck pain, but this is a subjective measure, and a more objective decision support system, that gives a reliable and more detailed analysis of neck movement pattern, is needed. The objective of this study was to evaluate the predictive ability of a BPNN, using neck movement variables as input. Three-dimensional (3-D) neck movement data from 59 subjects with WAD and 56 control subjects were collected with a ProReflex system. Rotation angle and angle velocity were calculated using the instantaneous helical axis method and motion variables were extracted. A principal component analysis was performed in order to reduce data and improve the BPNN performance. BPNNs with six hidden nodes had a predictivity of 0.89, a sensitivity of 0.90 and a specificity of 0.88, which are very promising results. This shows that neck movement analysis combined with a neural network could build the basis of a decision support system for classifying suspected WAD, even though further evaluation of the method is needed.

  • 22.
    Holmner, Åsa
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Medicine, Department of Epidemiology and Global Health.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Bergmann, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Blomberg, Anders
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Wadell, Karin
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    How stable is lung function in patients with stable chronic obstructive pulmonary disease when monitored using a telehealth system?: A longitudinal and home-based study2020In: BMC Medical Informatics and Decision Making, E-ISSN 1472-6947, Vol. 20, no 1, article id 87Article in journal (Refereed)
    Abstract [en]

    Background: Many telehealth systems have been designed to identify signs of exacerbations in patients with chronic obstructive pulmonary disease (COPD), but few previous studies have reported the nature of recorded lung function data and what variations to expect in this group of individuals. The aim of the study was to evaluate the nature of individual diurnal, day-to-day and long-term variation in important prognostic markers of COPD exacerbations by employing a telehealth system developed in-house.

    Methods: Eight women and five men with COPD performed measurements (spirometry, pulse oximetry and the COPD assessment test (CAT)) three times per week for 4-6 months using the telehealth system. Short-term and long-term individual variations were assessed using the relative density and weekly means respectively. Quality of the spirometry measurements (forced expiratory volume in one second (FEV1) and inspiratory capacity (IC)) was assessed employing the criteria of American Thoracic Society (ATS)/European Respiratory Society (ERS) guidelines.

    Results: Close to 1100 measurements of both FEV1 and IC were performed during a total of 240 patient weeks. The two standard deviation ranges for intra-individual short-term variation were approximately +/- 210 mL and +/- 350 mL for FEV1 and IC respectively. In long-term, spirometry values increased and decreased without notable changes in symptoms as reported by CAT, although it was unusual with a decrease of more than 50 mL per measurement of FEV1 between three consecutive measurement days. No exacerbation occurred. There was a moderate to strong positive correlation between FEV1 and IC, but weak or absent correlation with the other prognostic markers in the majority of the participants.

    Conclusions: Although FEV1 and IC varied within a noticeable range, no corresponding change in symptoms occurred. Therefore, this study reveals important and, to our knowledge, previously not reported information about short and long-term variability in prognostic markers in stable patients with COPD. The present data are of significance when defining criteria for detecting exacerbations using telehealth strategies.

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  • 23.
    Hoshi, Kei
    et al.
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Nyberg, Annakarin
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Bridging the contextual reality gap in blended reality space: the case of AGNES2011In: Include 2011 Proceedings: the role of inclusive design in making social innovation happen, 2011Conference paper (Refereed)
    Abstract [en]

    This research explores where the contextual reality gap emerges in social sharing of knowledge, understanding and experience generated between users (also between a designer and a user) in different contexts. It then examines how this 'contextual reality gap' can be bridged effectively in the sharing of meaning through mediated communication within emergent virtual/physical space, in what we call Blended Reality Space. As a concrete example, we refer to our current project, AGNES, developing User-sensitive Home-based Systems for Successful Ageing in a Networked Society, funded under the Ambient Assisted Living (AAL) Joint programme. Finally, we propose a conceptual framework for managing, structuring and composing contexts in designing interactive systems, a new approach we refer to as the Contextual Reality Framework.

  • 24.
    Hoshi, Kei
    et al.
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University Hospital, Umeå, Sweden.
    Nyberg, Annakarin
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Designing blended reality space: conceptual foundations and applications2011In: BCS-HCI '11: Proceedings of the 25th BCS Conference on Human-Computer Interaction, 2011, p. 217-226Conference paper (Refereed)
    Abstract [en]

    The present paper starts with a crucial discussion about the imbalance between technological and human concerns in the context of human-computer interaction, an imbalance that has arisen partly from the mechanistic aspect and its impact on interaction design. We then introduce the concept of Blended Reality Space, interactive mixed reality environments where the physical and the virtual are seamlessly combined and affect each other. The conceptual grounding and practical examples that illustrate our approach to interaction design are then discussed, adopting a standard figurative representation of blends. This helps understanding the role of blending that meaningfully bridges unbalanced separations between cognition and action, and the physical and the virtual. As a concrete example, the AGNES project, which is aimed at developing “user sensitive home-based systems for successful ageing in a networked society”, is introduced. We believe that the emphasis on ʻbalanceʼ or appropriate blending is very important in the development of better interactive systems for health, capitalizing on seamless combinations of the virtual and the physical in Blended Reality Space.

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  • 25.
    Höglund, Gustav
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Grip, Helena
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    The importance of inertial measurement unit placement in assessing upper limb motion2021In: Medical Engineering and Physics, ISSN 1350-4533, E-ISSN 1873-4030, Vol. 92, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Motion analysis using inertial measurement units (IMU) has emerged as an alternative to optical motion capture. However, the validity and reliability of upper limb measurements varies significantly between studies. The objective of this study was to determine how sensor placement affects kinematic output in the assessment of motion of the arm, shoulder, and scapula. IMUs were placed proximally/distally on arms, and medially/laterally on the scapula, in a group of eleven healthy participants, while performing nine different motion tasks. Linear regressions and mixed models analysed how these different sensor placements affected the estimated joint motion by establishing the linear relationship between sensors placed on the same body segment. The placement of sensors affected the measured kinematic output considerably, most prominent affect was seen for sensor placement on scapula during flexion and abduction, and on forearm during pronation/supination. The slope of the linear regression lines was 2.5 during flexion, 2.7 during abduction, and 1.8 for forearm pronation/supination. The results of this study suggest that the forearm sensor should be placed on the dorsal side of the forearm, at the distal end; the upper arm sensor should be placed laterally, on the distal part of the arm; and the sensor on the scapula should be placed cranially, along the spine of scapula.

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  • 26. Lindberg, F
    et al.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Brodin, LA
    Grönlund, Christer
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Assessment of intramuscular activation patterns using ultrasound M-mode strain2013In: Journal of Electromyography & Kinesiology, ISSN 1050-6411, E-ISSN 1873-5711, Vol. 23, no 4, p. 879-885Article in journal (Refereed)
    Abstract [en]

    The intramuscular activation pattern can be connected to the motor unit recruitment strategy of force generation and fatigue resistance. Electromyography has earlier been used in several studies to quantify the spatial inhomogeneity of the muscle activation. We applied ultrasound M-mode strain to study the activation pattern through the tissue deformation. Correlation values of the strain at different force levels were used to quantify the spatial changes in the activation. The assessment was done including the biceps brachii muscle of 8 healthy subjects performing isometric elbow flexion contractions ranging from 0% to 80% of maximum voluntary contraction. The obtained results were repeatable and demonstrated consistent changes of the correlation values during force regulation, in agreement with previously presented EMG-results. Both intra-subject and inter-subject activation patterns of strain were considered along and transverse the fiber direction. The results suggest that ultrasound M-mode strain can be used as a complementary method to study intramuscular activation patterns with high spatial resolution.

    (C) 2013 Elsevier Ltd. All rights reserved.

  • 27. Lindberg, Frida
    et al.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Granåsen, Gabriel
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Brodin, Lars-Åke
    Grönlund, Christer
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Pennation angle dependency in skeletal muscle tissue doppler strain in dynamic contractions2011In: Ultrasound in Medicine and Biology, ISSN 0301-5629, E-ISSN 1879-291X, Vol. 37, no 7, p. 1151-1160Article in journal (Refereed)
    Abstract [en]

    Tissue velocity imaging (TVI) is a Doppler based ultrasound technique that can be used to study regional deformation in skeletal muscle tissue. The aim of this study was to develop a biomechanical model to describe the TVI strain's dependency on the pennation angle. We demonstrate its impact as the subsequent strain measurement error using dynamic elbow contractions from the medial and the lateral part of biceps brachii at two different loadings; 5% and 25% of maximum voluntary contraction (MVC). The estimated pennation angles were on average about 4° in extended position and increased to a maximal of 13° in flexed elbow position. The corresponding relative angular error spread from around 7% up to around 40%. To accurately apply TVI on skeletal muscles, the error due to angle changes should be compensated for. As a suggestion, this could be done according to the presented model.

  • 28. Loras, H.
    et al.
    Stensdotter, A. K.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Sigmundsson, H.
    Individual differences in timing of discrete and continuous movements: a dimensional approach2014In: Psychological Research, ISSN 0340-0727, E-ISSN 1430-2772, Vol. 78, no 2, p. 289-299Article in journal (Refereed)
    Abstract [en]

    This study investigated aspects of individual differences in timing of continuous and discontinuous movements to different pacing signals (auditory or visual), pacing intervals (500, 650, 800, 950 ms), and across effectors (dominant versus non-dominant hand). Correlation and principal component analysis demonstrated that a single statistical dimension accounted for up to 60 % of the explained variance in discontinuous tasks and 25 % of the variance in continuous tasks, when applied to performance obtained from tasks conducted with different effectors and at different pacing rates. Correlation analysis of factor scores representing effector and rate independent task performances showed that timing of discrete or continuous movements can be associated with modality independent mechanisms. Timing variability from discrete and continuous trials was not significantly correlated. This study goes beyond previous correlational work on individual differences in discrete and continuous movements, demonstrating that individual differences in discrete (event-based) or continuous (emergent) motor timing tasks can be modeled as distinctive statistical components with dissimilar capability to capture effector, rate, and modality independent variance.

  • 29. Lorås, H
    et al.
    Sigmundsson, H
    Talcott, JB
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Stensdotter, AK
    Timing continuous or discontinuous movements across effectors specified by different pacing modalities and intervals2012In: Experimental Brain Research, ISSN 0014-4819, E-ISSN 1432-1106, Vol. 220, no 3-4, p. 335-347Article in journal (Refereed)
    Abstract [en]

    Sensorimotor synchronization is hypothesized to arise through two different processes, associated with continuous or discontinuous rhythmic movements. This study investigated synchronization of continuous and discontinuous movements to different pacing signals (auditory or visual), pacing interval (500, 650, 800, 950 ms) and across effectors (non-dominant vs. non-dominant hand). The results showed that mean and variability of asynchronization errors were consistently smaller for discontinuous movements compared to continuous movements. Furthermore, both movement types were timed more accurately with auditory pacing compared to visual pacing and were more accurate with the dominant hand. Shortening the pacing interval also improved sensorimotor synchronization accuracy in both continuous and discontinuous movements. These results show the dependency of temporal control of movements on the nature of the motor task, the type and rate of extrinsic sensory information as well as the efficiency of the motor actuators for sensory integration.

  • 30.
    Lorås, H.
    et al.
    Trondheim, Norway.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Vasseljen, O.
    Trondheim, Norway.
    Stensdotter, A. K.
    Trondheim, Norway.
    Frame-difference analysis of video-recorded laser-beam projections2015In: Manual Therapy, ISSN 1356-689X, E-ISSN 1532-2769, Vol. 20, no 6, p. 879-883Article in journal (Refereed)
    Abstract [en]

    Laser beams have been applied in many human motion research contexts to project movements in specific motor tasks. Currently, there are no objective analysis methods for laser projection recordings. The principal aim of this study was to investigate the feasibility of quantifying motion by applying frame differencing and image analysis methods to video streams of laser beam projections. The laser projection was controlled by a mechanical device that produced pseudo random rotations. The 2D motion recorded by the video was compared with recordings obtained with an electromagnetic system where a sensor was fixed to the same device as the laser. High correlations in the time and frequency domains were found between the methods. We conclude that the proposed method can accurately quantify complex motion patterns from laser beam projections. (C) 2015 Elsevier Ltd. All rights reserved.

  • 31. Lorås, Håvard
    et al.
    Stensdotter, Ann-Katrin
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Sigmundsson, Hermundur
    Individual differences in motor timing and its relation to cognitive and fine motor skills2013In: PLOS ONE, E-ISSN 1932-6203, Vol. 8, no 7, p. e69353-Article in journal (Refereed)
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  • 32.
    Magaard, Gustaf
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation.
    Stålnacke, Britt-Marie
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation.
    Sörlin, Ann
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation.
    Öhberg, Fredrik
    Department of Radiation Sciences/Biomedical Engineering, University Hospital of Northern Sweden, Umeå, Sweden.
    Berggren, Stina
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation.
    Grollmuss, Emma
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation.
    Hu, Xiao-Lei
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation.
    Identifying sub-acute rehabilitation needs among individuals after transient ischaemic attack using rehab-compass as a simple screening tool in the outpatient clinic2019In: Journal of Rehabilitation clinical communications, E-ISSN 2003-0711, Vol. 2, article id 1000018Article in journal (Refereed)
    Abstract [en]

    Objective: To evaluate comprehensive unmet rehabilitation needs by using a novel graphic screening tool, Rehab-Compass, among individuals in the sub-acute stage after first-ever transient ischaemic attack.

    Methods: A pilot prospective cohort study investigated 47 individuals with first-ever transient ischaemic attack in an outpatient clinic setting. By using Rehab-Compass, based on well-validated patient-reported outcome measure questionnaires, this study examined comprehensive unmet rehabilitation needs among individuals at 4-month follow-up after the onset of transient ischaemic attack.

    Results: Rehab-Compass identified that most participants were independent in their daily lives (modified Rankin Scale; mRS 0–1) with a relatively good quality of life (median EuroQol 5 dimensions (EQ-5D) 0.85), but certain limitations in participation in their daily lives. Rehab-Compass showed that, at 4 months after transient ischaemic attack, the most common condition affected was mood (reported by 89% of participants), followed by bladder function (70%), sexual life (52%), strength (51%) and fatigue (26%). Symptoms of depression and anxiety were reported by 6% and 17% of participants, respectively.

    Conclusion: This pilot study indicates that Rehab-Compass might be a suitable simple screening tool for use in the outpatient clinic setting to identify the multidimensional rehabilitation needs of individuals after transient ischaemic attack.

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  • 33.
    Mejtoft, Thomas
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lindahl, Olof
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Öhberg, Fredrik
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Pommer, Linda
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Jonzén, Karolina
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Andersson, Britt M.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Eklund, Anders
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Wåhlin, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Hallberg, Per
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Medtech innovation guide: an empiric model to support medical technology innovation2022In: Health and Technology, ISSN 2190-7188, E-ISSN 2190-7196, Vol. 12, no 5, p. 911-922Article in journal (Refereed)
    Abstract [en]

    Innovation has become increasingly important for most industries to cope with rapid technological changes as well as changing societal needs. Even though there are many sectors with specific needs when it comes to supporting innovation, the medical technology sector is facing several unique challenges that both increases the lead-time from idea to finished product and decreases the number of innovations that are developed. This paper presents a proposed innovation guide that has been developed and evaluated as a support for the innovation process within medical technology research. The guide takes the unique characteristics of the medical technology sector into account and serves as a usable guide for the innovator. The complete guide contains both a structure for the process and a usable web application to support the journey from idea to finished products and services. The paper also includes a new readiness level, Sect. 4.2 to provide support both when developing and determining the readiness for clinical implementation of a medical technology innovation.

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  • 34.
    Muala, Ala
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Österdahl, Rebecka
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Sehlstedt, Maria
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Rankin, Gregory
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Pourazar, Jamshid
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Bosson, Jenny A.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Thermochemical Energy Conversion Laboratory, Umeå University, Umeå, Sweden.
    Lindgren, Robert
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Thermochemical Energy Conversion Laboratory, Umeå University, Umeå, Sweden.
    Lopez, Natxo Garcia
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Thermochemical Energy Conversion Laboratory, Umeå University, Umeå, Sweden.
    Behndig, Annelie F.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Blomberg, Anders
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Sandström, Thomas
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Small airways effects of exposure to wood smoke2019In: European Respiratory Journal, ISSN 0903-1936, E-ISSN 1399-3003, Vol. 54Article in journal (Other academic)
  • 35.
    Månsson, Linda
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Bäckman, Pernilla
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Sandlund, Jonas
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Selling, Jonas
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Sandlund, Marlene
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Evaluation of Concurrent Validity between a Smartphone Self-Test Application and Clinical Tests for Balance and Leg Strength2021In: Sensors, E-ISSN 1424-8220, Vol. 21, no 5, article id 1765Article in journal (Refereed)
    Abstract [en]

    The evolving use of sensors to objectively assess movements is a potentially valuable addition to clinical assessments. We have developed a new self-test application prototype, MyBalance, in the context of fall prevention aimed for use by older adults in order to independently assess balance and functional leg strength. The objective of this study was to investigate the new self-test application for concurrent validity between clinical instruments and variables collected with a smartphone. The prototype has two test procedures: static standing balance test in two positions, and leg strength test performed as a sit-to-stand test. Thirty-one older adults were assessed for balance and functional leg strength, in an outpatient physiotherapy setting, using seven different clinical assessments and three sensor-tests. The results show that clinical instruments and sensor measurements correlate to a higher degree for the smartphone leg strength test. For balance tests, only a few moderate correlations were seen in the Feet Together position and no significant correlations for the Semi Tandem Stance. This study served as a first step to develop a smartphone self-test application for older adults to assess functional balance at home. Further research is needed to test validity, reliability, and user-experience of this new self-test application.

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  • 36.
    Månsson, Linda
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Wiklund, Maria
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Danielsson, Karin
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Sandlund, Marlene
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation.
    Co-Creation with Older Adults to Improve User-Experience of a Smartphone Self-Test Application to Assess Balance Function2020In: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 17, no 11, article id 3768Article in journal (Refereed)
    Abstract [en]

    This co-creation study aimed to develop a smartphone self-test application for balance and leg strength in collaboration between older adults and the research team. The paper describes older participants' preferences for, and their contribution to, the application design. Technology to assess movements is available in smartphones with built-in sensors, and one of the challenges is to develop a valuable self-test for older adults. The participants contributed to the design of the application's instructions and user interface. Multiple data collection methods were used: user-test with Think aloud method, mock-ups, homework assignment as co-researcher, audio and video recordings. Qualitative content analysis with a deductive-inductive approach was used, guided by the Optimized Honeycomb model for user experience (UX) as a categorization matrix. The analysis resulted in 17 subcategories within the seven facets of the UX Honeycomb model (findable, accessible, usable, desirable, credible, useful, and valuable), and describes the older participants' preferences and experiences. The main results were participants' desire to know why, to get clear and appropriate information, and expectations of the self-test to be useful. It was feasible and valuable to develop the self-test application in co-creation with the intended user-group, in order to get direct feedback and suggestions for the development.

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  • 37.
    Peter, Christian
    et al.
    Graz University ofTechnology, Inffeldgasse 16c, 8010 Graz, Austria.
    Kreiner, Andreas
    Modernfamilies.net GmbH, Linz, Austria.
    Schröter, Martin
    Graz University ofTechnology, Inffeldgasse 16c, 8010 Graz, Austria.
    Kim, Hyosun
    Graz University ofTechnology, Inffeldgasse 16c, 8010 Graz, Austria.
    Beiber, Gerald
    Fraunhofer IGD, Rostock, Germany.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Hoshi, Kei
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Waterworth, Eva
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Waterworth, John
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Ballesteros, Soladad
    Facultad de Psicologia, UNED, Madrid, Spain.
    AGNES: connecting people in a multimodal way2013In: Journal on Multimodal User Interfaces, ISSN 1783-7677, E-ISSN 1783-8738, Vol. 7, no 3, p. 229-245Article in journal (Refereed)
    Abstract [en]

    Western societies are confronted with a number of challenges caused by the increasing number of older citizens. One important aspect is the need and wish of older people to live as long as possible in their own home and maintain an independent life. As people grew older, their social networks disperse, with friends and families moving to other parts of town, other cities or even countries. Additionally, people become less mobile with age, leading to less active participation in societal life. Combined, this normal, age-related development leads to increased loneliness and social isolation of older people, with negative effects on mental and physical health of those people. In the AGNES project, a home-based system has been developed that allows connecting elderly with their families, friends and other significant people over the Internet. As most older people have limited experience with computers and often special requirements on technology, one focus of AGNES was to develop with the users novel technological means for interacting with their social network. The resulting system uses ambient displays, tangible interfaces and wearable devices providing ubiquitous options for interaction with the network, and secondary sensors for additionally generating carefully chosen information on the person to be relayed to significant persons. Evaluations show that the chosen modalities for interaction are well adopted by the users. Further it was found that use of the AGNES system had positive effects on the mental state of the users, compared to the control group without the technology.

  • 38. Rasouli, Omid
    et al.
    Fors, Egil A.
    Borchgrevink, Petter Chr
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Stensdotter, Ann-Katrin
    Gross and fine motor function in fibromyalgia and chronic fatigue syndrome2017In: Journal of Pain Research, E-ISSN 1178-7090, Vol. 10, p. 303-309Article in journal (Refereed)
    Abstract [en]

    Purpose: This paper aimed to investigate motor proficiency in fine and gross motor function, with a focus on reaction time (RT) and movement skill, in patients with fibromyalgia (FM) and chronic fatigue syndrome (CFS) compared to healthy controls (HC). Methods: A total of 60 individuals (20 CFS, 20 FM, and 20 HC), age 19-49 years, participated in this study. Gross motor function in the lower extremity was assessed using a RT task during gait initiation in response to an auditory trigger. Fine motor function in the upper extremity was measured during a precision task (the Purdue Pegboard test) where the number of pins inserted within 30 s was counted. Results: No significant differences were found between FM and CFS in any parameters. FM and CFS groups had significantly longer RT than HC in the gait initiation (p=0.001, and p=0.004 respectively). In the Purdue Pegboard test, 20% in the FM group, 15% in the CFS groups, and 0% of HC group, scored below the threshold of the accepted performance. However, there were no significant differences between FM, CFS, and HC in this task (p=0.12). Conclusion: Compared to controls, both CFS and FM groups displayed significantly longer RT in the gait initiation task. Generally, FM patients showed the worst results in both tests, although no group differences were found in fine motor control, according to the Purdue Pegboard test.

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  • 39.
    Rehn, Börje
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Stenlund, Tobias
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Öhberg, Fredrik
    Lindroos, Ola
    Lundström, Ronnie
    Analysis of seated postures using orientation sensors2012Conference paper (Refereed)
  • 40.
    Sehlin, Maria
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Brändström, Helge
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Winsö, Ola
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Haney, Michael
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Wadell, Karin
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Simulated flying altitude and performance of continuous positive airway pressure devices2014In: Aviation, Space and Environmental Medicine, ISSN 0095-6562, E-ISSN 1943-4448, Vol. 85, no 11, p. 1092-1099Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: Continuous positive airway pressure (CPAP) is used in air ambulances to treat patients with impaired oxygenation. Differences in mechanical principles between CPAP devices may affect their performance at different ambient air pressures as will occur in an air ambulance during flight. METHODS: Two different CPAP systems, a threshold resistor device and a flow resistor device, at settings 5 and 10 cm H2O were examined. Static pressure, static airflow and pressure during simulated breathing were measured at ground level and at three different altitudes (2400 m (8 kft), 3000 m (10 kft) and 10700 m (35 kft)). RESULTS: When altitude increased, the performance of the two CPAP systems differed during both static and simulated breathing pressure measurements. With the threshold resistor CPAP, measured pressure levels were close to the preset CPAP level. Static pressure decreased 0.71 ± 0.35 cm H2O, at CPAP 10 cm H2O, comparing ground level and 35 kft. With the flow resistor CPAP, as the altitude increased CPAP produced pressure levels increased. At 35 kft, the increase was 5.13 ± 0.33 cm H2O at CPAP 10 cm H2O. DISCUSSION: The velocity of airflow through the flow resistor CPAP device is strongly influenced by reduced ambient air pressure leading to a higher delivered CPAP effect than the preset CPAP level. Threshold resistor CPAP devices seem to have robust performance regardless of altitude. Thus, the threshold resistor CPAP device is probably more appropriate for CPAP treatment in an air ambulance cabin, where ambient pressure will vary during patient transport.

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  • 41.
    Sehlin, Maria
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Sandkvist Törnell, Siv
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Johansson, Göran
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Winsö, Ola
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Pneumatic performance of the boussignac CPAP system in healthy humans2011In: Respiratory care, ISSN 0020-1324, E-ISSN 1943-3654, Vol. 56, no 6, p. 818-826Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The Boussignac CPAP has been found to effectively treat acute pulmonary oedema. However, data on airway pressure in association with the Boussignac CPAP are sparse. We therefore designed this study to evaluate the stability of the Boussignac CPAP in terms of maintaining adequate inspiratory and expiratory pressure levels. We also wanted to evaluate the perceived exertion when breathing with the Boussignac CPAP.

    METHODS: Continuous recordings of airway pressure and airflow were made in 18 healthy volunteers during breathing with the Boussignac CPAP at 5, 7.5 and 10 cm H₂O for three sessions of 10 minutes at each CPAP level. Participants were blinded for the sequential order of the investigated CPAP levels. They terminated each session, at the respective CPAP level, by taking 10 forced breaths.

    RESULTS: During 10 minutes normal breathing periods, when participants breathed at 20 % of their VC with a peak expiratory airflow of 14 % of FEV₁, the maximal pressure difference was 4.0 cm H₂O between inspiration and expiration at CPAP 10 cm H₂O. Changes in airway pressure were never large enough to reduce airway pressure below zero. When taking forced breaths, expiratory volume was 38-42 % of VC and peak expiratory airflow was 49-56 % of FEV ₁. As airflow increased, both the drop in inspiratory airway pressure and the increase in expiratory airway pressure were enhanced.

    CONCLUSIONS: Pressure changes during breathing with CPAP are considered to be associated with increased work of breathing. The pneumatic performance of the Boussignac CPAP is adequate during normal breathing with low airflow. However, during forced breathing resulting in increased airflow, the Boussignac CPAP is unable to maintain stable airway pressure levels, possibly resulting in increased work of breathing and respiratory fatigue. Thus, the Boussignac CPAP system might be less suitable for patients breathing at a higher frequency.

  • 42.
    Sehlin, Maria
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Winsö, Ola
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Wadell, Karin
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Immediate effects of positive expiratory pressure and continuous positive airway pressure breathing on changes in inspiratory capacity as an indirect measure of induced changes in functional residual capacity in healthy individualsManuscript (preprint) (Other academic)
    Abstract [en]

    Introduction: Positive expiratory pressure (PEP) and continuous positive airway pressure (CPAP) are used to enhance breathing parameters such as functional residual capacity (FRC) in patients. Studies comparing effects of PEP and CPAP on FRC are sparse. One reason for this may be that sophisticated equipment, not suitable in the clinical setting, is required. Total lung capacity consists of inspiratory capacity (IC) and FRC and a change in IC should therefore result in a corresponding change in FRC. We aimed to investigate if PEP and CPAP induced changes in IC could be used as an indirect measure of changes in FRC and also to evaluate immediate effects of PEP and CPAP devices, with different kinds of resistors, on IC. 

    Methods: 20 healthy volunteers breathed with two PEP devices, a PEP-mask (flow resistor) and a PEP-bottle (threshold resistor) and two CPAP devices, a flow resistor device and a threshold resistor device, in a randomized order. The measurement sequence consisted of 30 breaths with an IC measurement performed before and immediately after the 30th breath, while the participants were still connected to the respective breathing device. Perceived exertion of the respective 30 breaths was measured with Borg CR10 scale.

    Results: Three of the four breathing devices, the PEP-mask and the two CPAP devices, significantly decreased IC (p < 0.001). Median perceived exertion was quite low for all four breathing devices but the difference in perceived exertion within the different breathing devices was large.

    Conclusion: When measured in direct continuation of PEP and CPAP breathing, changes in IC could be used as an indirect measure of changes in FRC. All investigated breathing devices except the PEP-bottle decreased IC, i.e. increased FRC.

  • 43.
    Sehlin, Maria
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy. Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Winsö, Ola
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Wadell, Karin
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Inspiratory Capacity as an Indirect Measure of Immediate Effects of Positive Expiratory Pressure and CPAP Breathing on Functional Residual Capacity in Healthy Subjects2015In: Respiratory care, ISSN 0020-1324, E-ISSN 1943-3654, Vol. 60, no 10, p. 1486-1494Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Positive expiratory pressure (PEP) and CPAP are used to enhance breathing parameters such as functional residual capacity (FRC) in patients. Studies comparing effects of PEP and CPAP on FRC are few and variable. One reason for this may be that sophisticated equipment, not suitable in the clinical setting, is required. Because total lung capacity (TLC) consists of inspiratory capacity (IC) and FRC, a change in IC should result in a corresponding change in FRC given constant TLC. We aimed to evaluate the effects of different PEP and CPAP devices on IC as an indirect measure of induced changes in FRC from these devices in healthy subjects. METHODS: Twenty healthy subjects breathed with 2 PEP devices, a PEP mask (flow resistor) and a PEP bottle (threshold resistor), and 2 CPAP devices, a flow resistor and a threshold resistor, in a randomized order. The measurement sequence consisted of 30 breaths with an IC measurement performed before and immediately after the 30th breath while the subjects were still connected to the breathing device. Perceived exertion of the 30 breaths was measured with the Borg category ratio 10 scale. RESULTS: Three of the 4 breathing devices, the PEP mask and the 2 CPAP devices, significantly decreased IC (P <.001). Median perceived exertion was quite low for all 4 breathing devices, but the difference in perceived exertion among the different breathing devices was large. CONCLUSIONS: Provided that TLC is constant, we found that measurements of changes in IC could be used as an indirect measure of changes in FRC in healthy subjects. All investigated breathing devices except the PEP bottle decreased IC, as an indirect measure of increased FRC.

  • 44.
    Sehlin, Maria
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Johansson, Göran
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Winsö, Ola
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Physiological responses to positive expiratory pressure breathing: a comparison of the PEP bottle and the PEP mask2007In: Respiratory care, ISSN 0020-1324, E-ISSN 1943-3654, Vol. 52, no 8, p. 1000-1005Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: In the intensive care unit we have observed that patients have different adherence to 2 commonly used positive-expiratory-pressure (PEP) therapy devices: the PEP bottle and the PEP mask. The reason for this difference is not clear. METHODS: In a randomized prospective study, we made continuous recordings of airway pressure and airflow, with 20 healthy volunteers, with the PEP bottle and the PEP mask. The measurement sequence consisted of 3 sessions of 10 breaths with the PEP bottle and the PEP mask, in a randomized crossover design. A rest period of 15 min separated the PEP bottle and PEP mask measurements. RESULTS: With the PEP bottle the expiratory phase began with a zero-flow period of 0.39 s, during which airway pressure rose 11.9 cm H2O. With the PEP bottle the mean expiratory pressure was 11.7 cm H2O, and end-expiratory pressure was 9.5 cm H2O. With the PEP mask the initial expiratory zero-flow period was almost nonexistent (0.04 s) and without any change in airway pressure. With the PEP mask the shape of the expiratory pressure curve was different; mean expiratory pressure was 8.6 cm H2O, and end-expiratory pressure was zero. With the PEP bottle the inspiration also began with a zero-flow period of 0.43 s, during which airway pressure decreased 9.6 cm H2O from the end-expiratory airway pressure. With the PEP mask the initial inspiratory zero-flow period was only 0.01 s and there was no concomitant change in airway pressure. CONCLUSIONS: The PEP bottle and the PEP mask showed major differences in the relationship between airflow and airway pressure. These findings might explain the observed differences in patient adherence to these therapies.

  • 45.
    Stenlund, Tobias
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Lindroos, Ola
    Rehn, Börje
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Seated postural loads caused by shock-type whole-body vibration when driving over obstacles2020In: International Journal of Forest Engineering, ISSN 1494-2119, E-ISSN 1913-2220, Vol. 31, no 3, p. 184-191Article in journal (Refereed)
    Abstract [en]

    Operators of mobile machines within forestry work long hours in seated postures while being exposed to whole-body vibration (WBV) that is associated with pain in the lower back and neck. Still, little is known about the contribution from postural loads. In this study postural loads and shock-type WBV exposure on drivers operating a forwarder during terrain-like conditions was measured and quantified using inertial measurement units (IMUs). Five male drivers drove a forwarder repeatedly over standardized steel obstacles using a predefined speed and posture followed by driving over natural obstacles along a terrain course using a self-selected speed and posture. IMUs were affixed along the spine, on the back of the head of the driver and on the seat to detect orientation, velocity, and acceleration. The result shows that the methodology for measuring WBV and postural load with IMUs is feasible. Postural loads, expressed as range of motions (ROMs), when driving over a single standardized obstacle at a speed of 3.3 km/h were up to 21 degrees in the neck segments. Increasing vehicle speed and size of obstacles increased postural loads. The terrain course resulted in higher ROMs in all body segments compared to a standardized obstacle, a difference in sideway seat acceleration but no differences regarding angular velocities of the head. Mechanical shocks at the seat were prevalent but the action limit value was exceeded only for one driver. Postural loads remained small during all conditions indicating that the spine can remain stable during exposure to shock-type WBV of this nature.

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  • 46.
    Stenlund, Tobias
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Rehn, Börje
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Lindroos, Ola
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Assessing postural load among drivers exposed to shock-type whole-body vibration using inertial measurements units: Results from measurements on standardized courses2019Conference paper (Refereed)
    Abstract [en]

    Background: Lower back and neck pain is common among persons who drive vehicles in their profession. The vehicle occupants are exposed to whole-body vibration (WBV) that may include mechanical shocks which are believed to increase the likelihood of injury further. Mechanical shocks are especially generated when driving on rough terrain and may challenge drivers' postural equilibrium. Little is known about the contribution of postural load to injury risk and thus objective measurements are necessary.

    Purpose: The purpose of the study was to assess the feasibility of registering and analyzing seated postural load and shock-type WBV synchronously using inertial measurement units (IMUs) among drivers of forest machines during terrain-like conditions.

    Methods: Five male participants (18-34 years old) drove a forest machine 6 times over three different standardized steal obstacles along a gravel course using a predefined speed and posture. Participants then drove the same vehicle 3 times over natural obstacles along a terrain course using a self-selected speed and posture. Three IMUs were affixed along the spine (at S2, Th2 and C4) and one to the head of participants as well as one to the seat. Data from the IMUs regarding accelerations and orientation in sagittal, frontal and horizontal plane were then analyzed.

    Results: Postural load, expressed as the range of motions (ROMs) in the upper neck, lower neck, trunk and pelvis were less than 22° in all directions during maneuvers on the standardized course. The size of obstacle and the vehicle speed had significant effects on the ROMs. No significant differences between courses were evident regarding seat accelerations and angular velocities at the drivers head. The WBV analysis of the terrain course indicated that mechanical shocks were prevalent but exceeded the exposure action value for only one driver and not the exposure limit value according to health and safety requirements within the European Union (EU directive 2002/44/EC).

    Conclusion(s): IMUs may objectively be used to register and present seated postural load and shock-type WBV exposure synchronously when driving on terrain. There seems to be a low risk of injuries from mechanical shocks since the magnitude of postural load (ROMs) during tested conditions was not considered to increase injury risk even though vehicle speed and the size of obstacles had a significant effect.

    Implications: Postural load when driving a forest machine during terrain-like conditions appears low in this study but more long-term field measurements on more drivers are needed before definite conclusions can be made. IMUs are regarded as promising tools for registering and representing seated postural load and shock-type WBV exposure. Future development could provide drivers with feedback regarding potentially injurious postures and/or high shock-type WBV exposure.

  • 47.
    Stenlund, Tobias
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Lindroos, Ola
    Institutionen för skogens biomaterial och teknologi (SBT), Sveriges lantbruksuniversitet, Umeå.
    Häger, Charlotte
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Neely, Gregory
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Rehn, Börje
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Adaptation of postural reactions in seated positions and influence of head posture when exposed to a single sideway perturbation: relevance for driving on irregular terrain2016In: Journal of Novel Physiotherapy and Physical Rehabilitation, ISSN 2455-5487, Vol. 3, no 1, p. 022-029Article in journal (Refereed)
    Abstract [en]

     Background and objectives: Mechanical perturbations in seated positions caused by driving on irregular terrain destabilize the driver which, combined with the drivers’ posture, may cause musculoskeletal disorders. The aim of this study was to investigate adaptation and the effect of different head postures on seated postural reactions caused by perturbations. 

    Materials and Methods: Twenty healthy male participants, aged 18-43 years, were tested on a movable platform delivering 15 sideways perturbations (peak acceleration 13.3 m/s2) while the participants held their head in a neutral or a laterally flexed posture. Surface electromyography (EMG) signals were recorded bilaterally in upper neck, trapezius, erector spinae and external oblique, while kinematics were recorded with inertial sensors for the head, trunk and pelvis. EMG amplitudes, muscle onset latencies and angular displacements in the frontal plane were analyzed. 

    Results: In the neutral position, the EMG amplitudes and neck angular displacements significantly decreased by 0.2% and more than 1.6° respectively after repeated perturbations. Muscle onset latencies remained unchanged. During lateral flexion of the head, the EMG amplitudes decreased by 0.5% but the muscular onset latencies increased by more than 9 ms. 

    Conclusion: The developed neuromuscular strategy seem to prefer a reduced EMG amplitude. The modest size of the postural reactions during the conditions presented here do not by themselves explain the musculoskeletal disorders found in drivers.

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  • 48.
    Stenlund, Tobias
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Lindroos, Ola
    Häger, Charlotte
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Neely, Gregory
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Rehn, Börje
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Double-sided Mechanical Shocks Provoke Larger Seated Postural Reactions Compared to Single-Sided Mechanical Shocks2018In: Spine, ISSN 0362-2436, E-ISSN 1528-1159, Vol. 43, no 8, p. E482-E487Article in journal (Refereed)
    Abstract [en]

    STUDY DESIGN: Human volunteers were exposed experimentally to single-sided mechanical shocks (SSMS) and double-sided mechanical shocks (DSMS) while seated.

    OBJECTIVE: To describe and contrast seated postural reactions due to SSMS or DSMS in healthy male adults.

    SUMMARY OF BACKGROUND DATA: Mechanical shocks to the body, caused when driving on irregular terrain, are suggested to be hazardous to the spine and may be associated with the reported musculoskeletal pain of the back and neck among professional drivers. However, very little is known about the characteristics of seated postural reactions and the biomechanical effects caused by mechanical shocks.

    METHODS: Twenty healthy male subjects (18-43 years old) were exposed while seated to 5 SSMS and 15 DSMS in lateral directions. The second acceleration in the DSMS was in the opposite direction to the first acceleration and was either fast, medium or slow depending on the speed of direction change. Surface electromyography (EMG) was recorded in muscles of the upper neck, trapezius, erector spinae and external oblique while kinematics were recorded with inertial sensors placed at the neck, trunk and pelvis. Muscle activity was normalized to maximum voluntary contractions (MVC).

    RESULTS: The EMG amplitudes were significantly higher (0.6-1%; p < 0.001) for the fast DSMS compared to all other shocks. Range of motion (ROM) of the neck and trunk was greater during the DSMS compared to the SSMS. Evoked muscle activity was less than 2% MVC in the trapezius, less than 10% MVC in the erector spinae and upper neck while the activity exceeded 10% MVC in the external oblique muscles.

    CONCLUSION: Fast DSMS in lateral directions appear more demanding compared to SSMS, demonstrating augmented seated postural reactions. However, the present mechanical shocks employed did not seem to induce postural reactions with regard to ROM or muscle activity of a magnitude likely to cause musculoskeletal overload.

    LEVEL OF EVIDENCE: 4.

  • 49.
    Stenlund, Tobias
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Lindroos, Ola
    Dept. of Forest Biomaterials & Technology, Swedish University of Agricultural Sciences, Sweden.
    Häger, Charlotte
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Rehn, Börje
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Inter- and intra-tester reliability when measuring seated spinal postures with inertial sensors2014In: International Journal of Industrial Ergonomics, ISSN 0169-8141, E-ISSN 1872-8219, Vol. 44, no 5, p. 732-738Article in journal (Refereed)
    Abstract [en]

    Prolonged awkward sitting postures may be associated with neck or back pain, but it is often unclear which specific postures cause most problems and which mechanisms that may underlie the pain. In order to increase the knowledge in this field, it seems crucial first of all to be able to analyse, in depth, different seated spinal postures. A problem is however the lack of reliable and direct measurement methods of the posture, especially for sitting. Recently developed systems with inertial sensor attached along the spine have potential for this purpose. The aim of the present study was therefore to test the reliability of using such a system to assess various seated postures. Inter- and intra-tester as well as intra-subject relative reliability was estimated with intra-class correlation coefficient (ICC). Absolute reliability was estimated with standard error of measurement (SEM) and smallest detectable change (SDC). Ten + ten healthy subjects and four testers participated. Three standardised unsupported seated postures (lumbar lordosis, lumbar kyphosis and neutral posture) and two standing postures (neutral and lumbar kyphosis) were evaluated using five sensors attached to the head, the thorax (high and low), the lumbar spine and the pelvis. The ICC for intra-tester reliability ranged from 0.37 to 0.90, SEM 2.5-12.0 degrees, and SDC 7.1-333 degrees where the largest measurement error was from the head. Intra-tester reliability was higher than inter-tester reliability but not as good as intra-subject reliability. The intra-tester absolute reliability was nevertheless not considered sufficient to distinguish smaller differences. The low reliability may depend on inertial sensor size and attachment but also on the tester's accuracy. This study shows that assessing unsupported seated spinal postures with inertial sensors could be performed with higher reliability if done by the same, rather than different, testers. Relevance to industry: Prolonged awkward seated postures at work may be associated with back and neck pain and should therefore be analysed. Inertial sensor units is a promising tool to measure spinal posture. Smaller sensors attached by one skilled tester directly onto the body will most likely improve assessment in the future. (C) 2014 Elsevier B.V. All rights reserved.

  • 50. Stensdotter, A.
    et al.
    Pedersen, N.
    Wanvik, A.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Flovig, J. C.
    Fors, E. A.
    Upper body 3-dimensional kinematics during gait in psychotic patients: a pilot-study2012In: Experimental Brain Research, ISSN 0014-4819, E-ISSN 1432-1106, Vol. 221, no 4, p. 393-401Article in journal (Refereed)
    Abstract [en]

    Gait is recognized as a key item related to mental function. Anomalous gait in psychotic individuals has been described for the lower extremities, whereas irregularities for upper body dynamics are not described, explained or verified with unbiased methods. Reduced walking velocity and increased somatic tension defined in this patient category may influence upper body dynamics during gait. The aim of this pilot-study was to describe upper body kinematics and investigate the biomechanical association with walking velocity and muscle tension. Twelve inpatients in a psychiatric ward with first-episode psychosis and 18 healthy control subjects walked at different self-chosen velocities. Movement and walking velocity were registered, and 3D kinematics was analysed for thorax and shoulder joint. Time-synchronized EMG from the trapezius muscle, chosen as indicator for general somatic tension, was analysed for maximal amplitude and variability. Results showed that patients walked with reduced arm swing at the shoulder joint and increased lateral thorax movements. Thorax rotations about the vertical axis, walking velocity and EMG measures were similar in patients and healthy subjects. The present study could not provide a biomechanical explanation for kinematic findings based on walking velocity or somatic tension.

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