| 1. |
- Ainegren, Mats, 1963-, et al.
(författare)
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Breathing resistance in automated metabolic systems is high in comparison with the Douglas Bag method and previous recommendations
- 2018
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part P. - : SAGE Publications. - 1754-3371. ; 232:2, s. 122-130
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate the resistance (RES) to breathing in metabolic systems used for the distribution and measurement of pulmonary gas exchange. A mechanical lung simulator was used to standardize selected air flow rates ( , L/s). The delta pressure (∆p, Pa) between ambient air and the air inside the equipment was measured in the breathing valve’s mouthpiece adapter for four metabolic systems and four types of breathing valves. RES for the inspiratory and expiratory sides was calculated as RES = ∆p / , Pa/L/s. The results for RES showed significant (p < 0.05) between-group variance among the tested metabolic systems, as well as the breathing valves and between most of the completed . The lowest RES among the metabolic systems was found for a Douglas Bag system, with approximately half of the RES compared to the automated metabolic systems. The automated systems were found to have higher RES already at low in comparison to previous recommendations. For the hardware components, the highest RES was found for the breathing valves while the lowest RES was found for the hoses. Conclusion: The results showed that RES in metabolic systems can be minimized through conscious choices of system design and hardware components.
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| 2. |
- 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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| 3. |
- Andersson, Dan, 1967-, et al.
(författare)
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Pedestrians' perceptions of route environments in relation to deterring or facilitating walking
- 2023
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Ingår i: Frontiers In Public Health. - : Frontiers Media S.A.. - 2296-2565. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundEvery walk takes place in a route environment, and it can play an important role in deterring or facilitating walking, and will always affect the environmental unwell – wellbeing of pedestrians. The aim of this study is to illuminate which the important route environmental variables are in this respect. The focus is therefore on pedestrians´ perceptions of route environmental variables and how they relate to overall appraisals of route environments as hindering – stimulating for walking and unsafe – safe for reasons of traffic. MethodsCommuting pedestrians in the inner urban area of Stockholm, Sweden (n = 294, 49.5 ± 10.4 years, 77% women), were recruited via advertisements. They evaluated their own commuting route environments using a self-report tool, the Active Commuting Route Environment Scale (ACRES). Correlation, multiple regression, and mediation analyses were used to study the relationships between the variables and the outcome variables. ResultsAesthetics and greenery appear to strongly stimulate walking, whereas noise, a proxy for motorized traffic, hinders it. Furthermore, aesthetics is positively related to traffic safety, whereas conflicts have the opposite role. Conflicts is an intermediate outcome, representing several basic environmental variables, whereof some were directly and negatively related to unsafe – safe traffic. Conclusion Route environmental variables appear to be potent factors in deterring or facilitating walking. This knowledge is of importance for policymakers and urban planners when designing route environments with the aim of attracting new pedestrians, and simultaneously stimulating those who already walk to keep on.
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| 4. |
- Andersson, Dan, 1967-, et al.
(författare)
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Trafikbuller – ett högljutt hot mot folkhälsan
- 2022
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- BakgrundRegelbunden fysisk aktivitet har positiva hälsoeffekter, och många vill vara fysiskt aktiva, men upplever inte sällan olika hinder för det, till exempel tidsbrist. Att gå eller cykla till arbetet är därför en intressant möjlighet i detta sammanhang, då fysiskt aktiv arbetspendling ofta är tidseffektivt. Dessutom krävs sällan någon specialutrustning, startsträckan är kort och avstånden kan anpassas så att man går, cyklar hela eller delar av sträckan mellan hem och arbetsplats. Om färdvägsmiljön dessutom upplevs som stimulerande och trygg kan den sannolikt bidra till att upprätthålla ett beteende, och på så vis medverka till att många individer får en angelägen ”dos” fysisk aktivitet. Studier av hur olika trafikvariabler samspelar, och hur dessa i sin tur påverkar vår uppfattning om en färdvägsmiljö ger inga entydiga svar. Syftet med denna studie var därför att studera de interna sambanden mellan fyra olika variabler relaterade till motortrafik: hastighet, flöde, buller och avgaser samt hur dessa, i olika kombinationer, inverkar på uppfattningen om en miljö är hindrande eller stimulerande respektive trygg eller otrygg för arbetspendling till fots.Metod294 arbetspendlande fotgängare (49.5 ± 10.4 år, 77 % kvinnor) rekryterades via annonser, och deras upplevelser av sina färdvägsmiljöer i Stockholms innerstad har nyttjats i våra analyser. Upplevelserna skattades med färdvägsmiljöskalan ”The Active Commuting Route Environment Scale” (ACRES). Den innehåller utfallsvariablerna hindrande-stimulerande färdvägsmiljö och otrygghet-trygghet i trafiken, samt ett antal miljöprediktorer, varav vi har nyttjat de fyra som är relaterade till motortrafik: flöde av motorfordon, hastighet, buller och avgaser. Såväl trafikvariabler som utfallsvariabler skattades med 15-gradiga skalor. För att analysera sambanden mellan trafikvariablerna och utfallsvariablerna användes multipla regressionsanalyser. ResultatAlla trafikvariabler var i sig själva negativt relaterade de båda utfallsvariablerna hindrande-stimulerande färdvägsmiljö och otrygghet-trygghet i trafiken. När istället de fyra trafikvariablerna analyserades samtidigt i förhållande till om miljön upplevdes som hindrande eller stimulerande samt otrygg eller trygg var det enbart buller som var negativt relaterad till de båda utfallsvariablerna. Hastighet hade en negativ roll i förhållande till trygghetsvariabeln. Analyserna visade dessutom att både flöde av motorfordon och hastighet förutspådde buller.SlutsatserSamtidigt som varje trafikvariabel är negativt relaterad till hur färdvägsmiljöer upplevs av fotgängare, framträder motorfordons buller och hastigheter som de variabler som är mest bekymmersamma för fotgängare. Studier som denna kan utgöra ett underlag för arbetet med att skapa attraktiva miljöer för fotgängare, och därmed bidra till bättre folkhälsa, förändrade pendlingsmönster i urbana miljöer samt ökad ekologisk hållbarhet.
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| 5. |
- 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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| 6. |
- Carlsson, Magnus, et al.
(författare)
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The effect of ball temperature on ball speed and carry distance in golf drives
- 2018
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part P. - London, UK : Sage Publications. - 1754-3371. ; 233:2, s. 186-192
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate the effect of ball temperature on impact ball speed and carry distance during golf drives in a blind randomized test design. The balls were exposed to a temperature-controlled environment (4 °C, 18 °C, 32 °C, and 46 °C) for 24 h prior to the test and each temperature group consisted of 30 balls. The 120 drives were performed by an elite male golfer (handicap: 0.0) in an indoor driving range. All drives were measured by a Doppler-radar system to determine the club-head speed, launch angle, spin rate, ball speed, and carry distance. Differences between the groups were investigated using a one-way analysis of variance. The results indicated that ball-speed and carry-distance differences occurred within the four groups (p < 0.001 and p < 0.01, respectively). The post hoc analyses showed that the ball temperatures of 18 °C and 32 °C had greater ball speeds and carry distances than balls at 4 °C and 46 °C (all p < 0.05). The intervals for the between-group differences were 0.6–0.7 m s –1 and 2.9–3.9 m for ball speed and carry distance, respectively. Hence, the results showed that ball temperature influences both the ball speed and the carry distance. Based on the findings in this study, standardization of ball temperature should be factored into governing body regulation tests for golf equipment. © IMechE 2018.
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| 7. |
- 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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| 8. |
- Dal Maso, Fabien, et al.
(författare)
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Coupling between 3D displacements and rotations at the glenohumeral joint during dynamic tasks in healthy participants.
- 2014
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Ingår i: Clinical Biomechanics. - : Elsevier BV. - 0268-0033 .- 1879-1271. ; 29:9, s. 1048-1055
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Glenohumeral displacements assessment would help to design shoulder prostheses with physiological arthrokinematics and to establish more biofidelic musculoskeletal models. Though displacements were documented during static tasks, there is little information on their 3D coupling with glenohumeral angle during dynamic tasks. Our objective was to characterize the 3D glenohumeral displacement-rotation couplings during dynamic arm elevations and rotations.METHODS: Glenohumeral displacements were measured from trajectories of reflective markers fitted on intracortical pins inserted into the scapula and humerus. Bone geometry was recorded using CT-scan. Only four participants were recruited to the experiment due to its invasiveness. Participants performed dynamic arm abduction, flexion and axial rotations. Linear regressions were performed between glenohumeral displacements and rotations. The pin of the scapula of one participant moved, his data were removed from analysis, and results are based on three participants.FINDINGS: The measurement error of glenohumeral kinematics was less than 0.15mm and 0.2°. Maximum glenohumeral displacements were measured along the longitudinal direction and reached up to +12.4mm for one participant. Significant couplings were reported especially between longitudinal displacement and rotation in abduction (adjusted R(2) up to 0.94).INTERPRETATION: The proposed method provides the potential to investigate glenohumeral kinematics during all kinds of movements. A linear increase of upward displacement during dynamic arm elevation was measured, which contrasts with results based on a series of static poses. The systematic investigation of glenohumeral displacements under dynamic condition may help to provide relevant recommendation for the design of shoulder prosthetic components and musculoskeletal models.
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| 9. |
- Elmgren Frykberg, Gunilla, 1957-, et al.
(författare)
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Temporal coordination of the sit-to-walk task in subjects with stroke and in controls
- 2009
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Ingår i: Archives of Physical Medicine and Rehabilitation. - : Elsevier BV. - 0003-9993 .- 1532-821X. ; 90:6, s. 1009-1017
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To explore events and describe phases for temporal coordination of the sit-to-walk (STW) task, within a semistandardized set up, in subjects with stroke and matched controls. In addition, to assess variability of STW phase duration and to compare the relative duration of STW phases between the 2 groups.Design: Cross-sectional.Setting: Research laboratory.Participants: A convenience sample of persons with hemiparesis (n=10; age 50–67y), more than 6 months after stroke and 10 controls matched for sex, age, height, and body mass index.Interventions: Not applicable.Main Outcome Measures: Relative duration of STW phases, SE of measurement in percentage of the mean, and intraclass correlation coefficients (ICCs).Results: Four STW phases were defined: rise preparation, transition, primary gait initiation, and secondary gait initiation. The subjects with stroke needed 54% more time to complete the STW task than the controls did. ICCs ranged from .38 to .66 and .22 to .57 in the stroke and control groups, respectively. SEs of measurement in percentage of the mean values were high, particularly in the transition phase: 54.1% (stroke) and 50.4% (controls). The generalized linear model demonstrated that the relative duration of the transition phase was significantly longer in the stroke group.Conclusions: The present results extend existing knowledge by presenting 4 new phases of temporal coordination of STW, within a semistandardized set-up, in persons with stroke and in controls. The high degree of variability regarding relative STW phase duration was probably a result of both the semistandardized set up and biological variability. The significant difference in the transition phase across the 2 groups requires further study.
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| 10. |
- 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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