Observation Methods and Imaging Techniques. Assessments of physical exposure in repetitive work with focus on neck and upper extremities

Abstract

Observation methods and imaging techniques - assessments of physical exposure in repetitive work with focus on neck and upper extremities



The aim of this thesis was to develop, establish and validate observation methods for exposure assessments in epidemiological studies of repetitive work. A second aim was to increase the quality of input data for biomechanical shoulder models, by reliability and validity studies of Magnetic Reso-nance Imaging (MRI) and Ultrasound Scanning (US).



The first study, a review of existing observation methods, showed that criteria for work posture classification in observation methods were mostly based on practical experience, but that also scien-tific criteria based on biomechanics, EMG and to some extent epidemiology constituted the criteria. More standardised observation methods were considered desirable.



In the next study a video-based observation method was developed for exposure assessments in an epidemiological follow-up study in 19 companies with repetitive work, the PRIM study (Project on Research and Intervention in Monotonous work). The observation method involved 43 variables re-presenting repetitiveness and level of exposure. Information on duration of exposure was obtained by means of a questionnaire. Based on work tasks, 103 exposure groups were formed, giving sufficient-ly large exposure contrasts between exposure groups and a sufficiently large homogeneity within groups for most of the variables studied. A large within-group variance in exposure to non-neutral shoulder postures may in future studies require individual assessment and/or the inclusion of groups with maximal contrast in exposure.



In the third and fourth study data from the PRIM observation method were compared with direct measurements. Work postures and movements were studied during poultry processing by means of the PRIM observation method and goniometers and inclinometers. Differences between the methods were mainly due to different reference positions and measured variables. Force demands as studied by force registrations from the deboner knife and EMG corresponded well with observer-based peak force ratings used as a variable in the PRIM observation method. The same study revealed that new technology during deboning of poultry (mechanical instead of manual deboning) had only a marginal effect on the physical workload.



In the fifth and sixth study imaging techniques were studied as techniques for quantifying muscle sizes and moment arms as input variables for biomechanical shoulder models used to quantify the in-ternal dose. MRI measurements of muscle sizes and moment arms of rotator cuff muscles were esti-mated to have a high reliability and validity. Data on muscle volumes, physiological cross-sectional areas and moment arms were added to the database of living healthy females representing the work-ing population. MRI values of muscle sizes and moment arms were reflected in the corresponding US values in m. supraspinatus and m. infraspinatus. US might thus be a valid alternative to MRI measurements, but further development and validation of the US technique are still required.

Abstract (Swedish)

Abstract in Danish

Observationsmetoder og billeddannelsesteknikker ? vurderinger af den fysiske eksponering i repetitivt arbejde med focus på nakke, skuldre og arme



Formålet var at udvikle, etablere og validere observationsmetoder til eksponeringsvurderinger i epidemiologiske undersøgelser af repetitivt arbejde. Et andet formål var at øge kvaliteten af input data til brug i biomekaniske skuldermodeller, ved hjælp af reliabilitets- og validitetsundersøgelser af metoderne Magnetisk Resonans (MRI) og Ultralyds Scanning (US).



Det første studie som var et litteraturstudie over eksisterende observationsmetoder viste, at bag-grunden for klassificering af arbejdsstillinger i observationsmetoder for det meste var baseret på praktisk erfaring, men at også videnskabelige kriterier baseret på biomekanik, EMG og i nogen grad epidemiologi udgjorde baggrunden. Det blev foreslået at anvende mere standardiserede observations-metoder i fremtidige studier.



I det næste studie blev en videobaseret observationsmetode udviklet til brug for eksponerings-vurderinger i et epidemiologisk follow-up studie i 19 virksomheder af repetitivt arbejde, PRIM studiet (Projekt om forskning og intervention i monotont arbejde). Observationsmetoden indeholdt 43 variabler og omfattede repetitivitet og eksponeringsniveau, medens eksponeringsvarighed blev oplyst gennem et spørgeskema. Baseret på arbejdsopgaverne blev 103 eksponeringsgrupper dannet, og disse viste sig at give tilstrækkelig stor eksponeringskontrast mellem de valgte eksponerings-grupper, samt en tilstrækkelig stor homogenitet indenfor grupperne for de fleste af de undersøgte variabler. Med hensyn til skulderens arbejdsstillinger registreredes store individuelle forskelle inden-for de enkelte grupper samtidig med en begrænset eksponeringskontrast mellem eksponerings-grupperne. I fremtidige studier bør dette problem løses ved enten at kræve individuelle eksponerings-mål og/eller inkludere grupper med større eksponeringskontrast.



I tredje og fjerde studie blev data fra PRIM observationsmetoden sammenlignet med direkte målinger. Arbejdsstillinger og bevægelser blev studeret ved processer med bearbejdning af kyllinger ved hjælp af PRIM observationsmetoden, goniometre og inclinometre. Forskelle mellem de to metoders resultater skyldtes fortrinsvis forskellige referencepositioner og målte variabler. Kraftkrav målt ved kraftregistreringer fra en udbenerkniv og EMG modsvarede spidsbelastninger vurderet udfra observationer, hvilket var en variabel i PRIM observationsmetoden. I samme studie blev det fundet at ny teknologi ved kyllingeudbening (maskinel i stedet for manuel udbening) kun havde en marginal effekt på det fysiske belastningsniveau.



I det femte og sjette studie blev billeddannelsesteknikker studeret som teknikker til at kvantificere muskelstørrelser og momentarme som inputvariabler i biomekaniske skulder modeller til at kvantificere den interne dosis. MRI målinger af muskelstørrelser og momentarme på rotator cuff musklerne blev vurderet til at have en høj reliabilitet og validitet. Data på muskel volumen, fysiolo-gisk tværsnitsareal og momentarme bidrager nu til databasen af levende raske kvinder i den erhvervs-aktive befolkning. MRI værdier af muskelstørrelser og momentarme blev genfundet i de tilsvarende Ultralyds værdier af m. supraspinatus og m. infraspinatus. Ultralyd kan på denne måde være et validt alternativ til MRI målinger, men yderligere udvikling og validering af Ultralydsteknikken til kvantifi-cering af muskelmål er påkrævet.

• author: Juul-Kristensen, Birgit
• supervisor: [unknown] [unknown]
• opponent: Docent Sundelin, Gunnevi
• organization: Human Movement: health and rehabilitation (research group)
• publishing date: 2001
• type: Thesis
• publication status: published
• subject: Physiotherapy
• keywords: imaging techniques, force, electromyography, video recording, electrogoniometer, inclinometer, movement, posture, physical exposure, industrial work, repetitive, upper extremity, neck, observation method, musculoskeletal, Yrkesmedicin, arbetsmiljömedicin, industrial medicine, Occupational health, epidemiology, ultrasound, magnetic resonance
• pages: 150 pages
• defense location: N/A
• defense date: 2001-03-28 10:15:00
• external identifiers: other:ISRN: LUMEDW/MEPT--1018--SE
• ISBN: 91-628-4687-6
• language: English
• LU publication?: yes
• additional info: The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Division of Physiotherapy (Closed 2012) (013042000)
• id: 84f576aa-63ee-4d9a-81e1-c53cb1e2fc98 (old id 41375)
• date added to LUP: 2016-04-04 13:38:20
• date last changed: 2018-11-21 21:15:18