| 1. |
- Arvidsson, Daniel, 1974, et al.
(författare)
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Re-examination of accelerometer data processing and calibration for the assessment of physical activity intensity.
- 2019
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Ingår i: Scandinavian Journal of Medicine and Science in Sports. - : John Wiley & Sons. - 0905-7188 .- 1600-0838. ; 29:10, s. 1442-1452
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Tidskriftsartikel (refereegranskat)abstract
- This review reexamines use of accelerometer and oxygen uptake data for assessment of activity intensity. Accelerometers capture mechanical work, while oxygen uptake captures the energy cost of this work. Frequency filtering needs to be considered when processing acceleration data. A too restrictive filter attenuates the acceleration signal for walking and, to a higher degree, for running. This measurement error affects shorter (children) more than taller (adults) individuals due to their higher movement frequency. Less restrictive filtering includes more movement related signals and provide measures that better capture mechanical work, but may include more noise. An optimal filter cut-point is determined where most relevant acceleration signals are included. Further, accelerometer placement affects what part of mechanical work being captured. While the waist placement captures total mechanical work and therefore contributes to measures of activity intensity equivalent by age and stature, the thigh and wrist placements capture more internal work and do not provide equivalent measures. Value calibration of accelerometer measures is usually performed using measured oxygen uptake with the metabolic equivalent of task (MET) as reference measure of activity intensity. However, the use of MET is not stringent and is not a measure of activity intensity equivalent by age and stature. A candidate measure is the mass-specific net oxygen uptake, VO2 net (VO2 tot - VO2 stand). To improve measurement of physical activity intensity using accelerometers, research developments are suggested concerning processing of accelerometer data, use of energy expenditure as reference for activity intensity, and calibration procedure with absolute versus relative intensity. This article is protected by copyright. All rights reserved.
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| 2. |
- Fridolfsson, Jonatan, 1992, et al.
(författare)
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Effects of Frequency Filtering on Intensity and Noise in Accelerometer-Based Physical Activity Measurements.
- 2019
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Ingår i: Sensors. - : MDPI. - 1424-8220. ; 19:9
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Tidskriftsartikel (refereegranskat)abstract
- In objective physical activity (PA) measurements, applying wider frequency filters than the most commonly used ActiGraph (AG) filter may be beneficial when processing accelerometry data. However, the vulnerability of wider filters to noise has not been investigated previously. This study explored the effect of wider frequency filters on measurements of PA, sedentary behavior (SED), and capturing of noise. Apart from the standard AG band-pass filter (0.29-1.63 Hz), modified filters with low-pass component cutoffs at 4 Hz, 10 Hz, or removed were analyzed. Calibrations against energy expenditure were performed with lab data from children and adults to generate filter-specific intensity cut-points. Free-living accelerometer data from children and adults were processed using the different filters and intensity cut-points. There was a contribution of acceleration related to PA at frequencies up to 10 Hz. The contribution was more pronounced at moderate and vigorous PA levels, although additional acceleration also occurred at SED. The classification discrepancy between AG and the wider filters was small at SED (1-2%) but very large at the highest intensities (>90%). The present study suggests an optimal low-pass frequency filter with a cutoff at 10 Hz to include all acceleration relevant to PA with minimal effect of noise.
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| 3. |
- Strömgren, Magnus, et al.
(författare)
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Modeling commuter modal shifts from car trips to cycling : Scenario construction and outcomes for Stockholm, Sweden
- 2020
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Ingår i: Journal of Transport Geography. - : Elsevier. - 0966-6923 .- 1873-1236. ; 86
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Tidskriftsartikel (refereegranskat)abstract
- This article presents the construction and outcomes of scenarios modeling commuter modal shift from car trips to cycling in the metropolitan region of Stockholm, the capital of Sweden. Building and improving upon previous studies in terms of both methodological approach and degree of spatial resolution of the modeling output, we examine scenarios where car commuters able to reach their workplace within 30 and 50 minutes of cycling shift commuting mode. Overall, car–bicycle modal shift figures were 31.6% and 48.7%, respectively. However, there were considerable geographical differences. While a substantial number of new bicycle commuters appeared in all five macro-level subdivisions of the study area, modal shift was by far the highest among car commuters living in the Inner City and its immediate surroundings.
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| 4. |
- Crommert, Martin Eriksson, 1974-, et al.
(författare)
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Trunk muscle activation at the initiation and braking of bilateral shoulder flexion movements of different amplitudes
- 2015
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Ingår i: PLOS ONE. - : PUBLIC LIBRARY SCIENCE. - 1932-6203. ; 10:11
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate if trunk muscle activation patterns during rapid bilateral shoulder flexions are affected by movement amplitude. Eleven healthy males performed shoulder flexion movements starting from a position with arms along sides (0°) to either 45°, 90° or 180°. EMG was measured bilaterally from transversus abdominis (TrA), obliquus internus (OI) with intra-muscular electrodes, and from rectus abdominis (RA), erector spinae (ES) and deltoideus with surface electrodes. 3D kinematics was recorded and inverse dynamics was used to calculate the reactive linear forces and torque about the shoulders and the linear and angular impulses. The sequencing of trunk muscle onsets at the initiation of arm movements was the same across movement amplitudes with ES as the first muscle activated, followed by TrA, RA and OI. All arm movements induced a flexion angular impulse about the shoulders during acceleration that was reversed during deceleration. Increased movement amplitude led to shortened onset latencies of the abdominal muscles and increased level of activation in TrA and ES. The activation magnitude of TrA was similar in acceleration and deceleration where the other muscles were specific to acceleration or deceleration. The findings show that arm movements need to be standardized when used as a method to evaluate trunk muscle activation patterns and that inclusion of the deceleration of the arms in the analysis allow the study of the relationship between trunk muscle activation and direction of perturbing torque during one and the same arm movement.
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| 5. |
- Nilsson, Johnny, et al.
(författare)
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Kinematic, kinetic and electromyographic adaptation to speed and resistance in double poling cross country skiing
- 2013
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 113:6, s. 1385-1394
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Tidskriftsartikel (refereegranskat)abstract
- This study incorporated variations in speed and the horizontal resistance acting upon elite female skiers during double poling (DP) on a treadmill and specifically analyzed biomechanical adaptations to these variations. Whole body kinematics and pole force data were recorded and used to calculate the moment of force acting on the shoulder and elbow joints. Data were obtained with a 3D optoelectronic system using reflective markers at given anatomical landmarks. Forces along the long axis of the right pole were measured with a piezoelectric force transducer. Surface electrodes were used to record EMG activity in the rectus femoris, rectus abdominis, latissimus dorsi and triceps brachii muscles. In a first set of recordings, the participants double poled with zero elevation at five different speeds from 8 to 17 km h(-1). In a second set of recordings, horizontal resistance was added by weights (0.4-1.9 kg) attached to a pulley system pulling the skier posteriorly during DP at 14 km h(-1). Results showed increasing relative duration of the thrust phase with increasing resistance, but not with speed. Significant kinematic differences occurred with increase in both speed and resistance. The mean (+/- SD) horizontal force components ranged between 1.7 (+/- 1.3) and 2.8 (+/- 1.1) percent (%) bodyweight (BW) in the speed adaptation and 3.1 (+/- 0.6) and 4.0 (+/- 1.3) % BW in the adaptation to horizontal resistance. Peak muscle activity showed a central to peripheral (proximo-distal) activation sequence. The temporal cycle phase pattern in the adaptation to speed and horizontal resistance differed.
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| 6. |
- Åberg, Anna Cristina, et al.
(författare)
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Calculations of mechanisms for balance control during narrow and single-leg standing in fit older adults: A reliability study.
- 2011
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Ingår i: Gait & Posture. - : Elsevier BV. - 0966-6362 .- 1879-2219. ; 34:3, s. 352-7
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Tidskriftsartikel (refereegranskat)abstract
- For older people balance control in standing is critical for performance of activities of daily living without falling. The aims were to investigate reliability of quantification of the usage of the two balance mechanisms M1 ‘moving the centre of pressure’ and M2 ‘segment acceleration’ and also to compare calculation methods based on a combination of kinetic (K) and kinematic (Km) data, (K–Km), or Km data only concerning M2. For this purpose nine physically fit persons aged 70–78 years were tested in narrow and single-leg standing. Data were collected by a 7-camera motion capture system and two force plates. Repeated measure ANOVA and Tukey's post hoc tests were used to detect differences between the standing tasks. Reliability was estimated by ICCs, standard error of measurement including its 95% CI, and minimal detectable change, whereas Pearson's correlation coefficient was used to investigate agreement between the two calculation methods. The results indicated that for the tasks investigated, M1 and M2 can be measured with acceptable inter- and intrasession reliability, and that both Km and K–Km based calculations may be useful for M2, although Km data may give slightly lower values. The proportional M1:M2 usage was approximately 9:1, in both anterio-posterior (AP) and medio-lateral (ML) directions for narrow standing, and about 2:1 in the AP and of 1:2 in the ML direction in single-leg standing, respectively. In conclusion, the tested measurements and calculations appear to constitute a reliable way of quantifying one important aspect of balance capacity in fit older people.
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| 7. |
- Andersson, Dan, 1967-, et al.
(författare)
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Pedestrians' perceptions of motorized traffic variables in relation to appraisals of urban route environments
- 2023
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 20:4
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Tidskriftsartikel (refereegranskat)abstract
- It is important to examine how motorized traffic variables affect pedestrians along a gradient from rural to inner urban settings. Relations between pedestrians' perceptions of four traffic variables and appraisals of route environments as hindering-stimulating for walking as well as unsafe-safe for reasons of traffic, were therefore studied in the inner urban area of Stockholm, Sweden (n = 294). The pedestrians rated their perceptions and appraisals with the Active Commuting Route Environment Scale (ACRES). Correlation, multiple regression, and mediation analyses were used to study the relationships between the traffic variables and the outcome variables. Noise related negatively to both hindering-stimulating for walking, and to unsafety-safety for traffic reasons. Vehicle speed related negatively to unsafety-safety for traffic reasons. Furthermore, vehicle speed protruded as an important origin of the deterring effects of traffic among those who commute by foot. The study shows the value of both partial and simultaneous analyses of the effect of all four traffic variables in relation to outcome variables relevant for walking.
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| 8. |
- Fridolfsson, Jonatan, 1992, et al.
(författare)
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Stronger association between high intensity physical activity and cardiometabolic health with improved assessment of the full intensity range using accelerometry
- 2020
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Ingår i: Sensors (Switzerland). - : MDPI AG. - 1424-8220. ; 20:4
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Tidskriftsartikel (refereegranskat)abstract
- © 2020 by the authors. Licensee MDPI, Basel, Switzerland. An improved method of physical activity accelerometer data processing, involving a wider frequency filter than the most commonly used ActiGraph filter, has been shown to better capture variations in physical activity intensity in a lab setting. The aim of the study was to investigate how this improved measure of physical activity affected the relationship with markers of cardiometabolic health. Accelerometer data and markers of cardiometabolic health from 725 adults from two samples, LIV 2013 and SCAPIS pilot, were analyzed. The accelerometer data was processed using both the original ActiGraph method with a low‐pass cut‐off at 1.6 Hz and the improved method with a low‐pass cut‐off at 10 Hz. The relationship between the physical activity intensity spectrum and a cardiometabolic health composite score was investigated using partial least squares regression. The strongest association between physical activity and cardiometabolic health was shifted towards higher intensities with the 10 Hz output compared to the ActiGraph method. In addition, the total explained variance was higher with the improved method. The 10 Hz output enables correctly measuring and interpreting high intensity physical activity and shows that physical activity at this intensity is stronger related to cardiometabolic health compared to the most commonly used ActiGraph method.
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| 9. |
- Nilsson Sommar, Johan, et al.
(författare)
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Overall health impacts of a potential increase in cycle commuting in Stockholm, Sweden
- 2022
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Ingår i: Scandinavian Journal of Public Health. - : Sage Publications. - 1403-4948 .- 1651-1905. ; 50, s. 552-564
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To estimate the overall health impact of transferring commuting trips from car to bicycle..Design and setting: In this study registry information on location of home and work for residents in the County of Stockholm was used to obtain the shortest travel route on a network of bicycle paths and roads. Current modes of travel to work were based on travel survey data. The relation between duration of cycling and distance cycled was established as a basis for selecting the number of individuals that normally would drive a car to their work place, but have a distance to work that they could bicycle within 30 minutes. The change in traffic flows was estimated by a transport model (LuTrans) and effects on road traffic injuries and fatalities were estimated by using national hospital injury data. Effects on air pollution concentrations were modelled using dispersion models.Results: Within the scenario, 111 000 commuters would shift from car to bicycle. This corresponds to 32% of the existing car commuters. On average the increased physical activity reduced the one-year mortality risk by 12% among the additional bicyclists corresponding to 16 fewer premature deaths per year. Including the number of years lost due to morbidity, the total number of disability adjusted life years (DALYs) gained was 696. The amount of DALYs per year gained in the general population due to reduced air pollution concentrations at home addresses was 471. The number of DALYs lost by traffic injuries was 176. Including also air pollution effects among bicyclists, the scenario was calculated to each year give a net benefit of 939 DALYs.Conclusion: The health impact assessment of transferring commuting by car to bicycle estimated large health benefits even then considering injuries and air pollution exposure among bicyclists.
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| 10. |
- Hedlund, Martin, et al.
(författare)
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BlocklyVR : Exploring Block-based Programming in Virtual Reality
- 2023
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Ingår i: MUM'23: Proceedings of the 22nd International Conference on Mobile and Ubiquitous Multimedia. - : Association for Computing Machinery. - 9798400709210 ; , s. 251-263
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Konferensbidrag (refereegranskat)abstract
- As programming is typically a static activity in front of a screen, we perform an initial exploration around the capabilities of block-based programming in the immersive space using Virtual Reality (VR) to make an early charting on how programming could involve moving the programmer's body. We created a block-based programming interface in a VR space called BlocklyVR based on the existing Blockly programming environment. To investigate programmer performance and experience in BlocklyVR, we conducted a controlled lab experiment (N = 20) with eight programming tasks that covered mathematical operations, if-statements, and function creation. Our initial exploration contributes by classifying movement types made by BlocklyVR programmers and reflecting on how these movements are related to the programming tasks. Additionally, our data suggests that participant performance in BlocklyVR was not affected compared to the 2D Blockly, even if participants were physically moving in VR space. We also found that the virtual reality sickness was marginal. Lastly, we identified four types of interaction that can potentially be employed by VR designers and developers aiming to convert a static task, like programming at a desk, into a "mobile"immersive experience. © 2023 Owner/Author.
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