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- Brorsson, Sofia
(författare)
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Biomechanical studies of finger extension function. Analysis with a new force measuring device and ultrasound examination in rheumatoid arthritis and healhty muscles
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Aims: The overall aim of this thesis was to further our understanding of extensor muscles and their role for hand function. The aims of the studies were: To develop and evaluate a new device for finger extensor force measurements. To evaluate ultrasound as a tool for assessment of muscle architecture. To determine the correlation between extensor muscle force and hand function. To evaluate the degree of impaired finger extensor force in rheumatoid arthritis (RA) and the correlation to impaired hand function. To analyse the effect of hand exercise in RA patients and healthy subjects with ultrasound and finger extension force measurements. Method: A new finger extension force measuring device was developed and an ultrasound based method was used to be able to objectively measure the finger extension force and analyze the static and dynamic extensor muscle architectures. Measurements were made of healthy volunteers (n=127) and RA patients (n=77) during uninfluenced and experimental conditions. A hand exercise program was performed and evaluated with hand force measurements, hand function test, patient relevant questionnaires (DASH and SF-36) and ultrasound measurements. Results: The new finger extension force measurement device was developed and then validated with measurements of accuracy as well as test-retest reliability. The coefficient of variation was 1.8 % of the applied load, and the test-retest reliability showed a coefficient of variation no more than 7.1% for healthy subjects. Ultrasound examination on m. extensor digitorum communis (EDC) showed significant differences between healthy men and healthy women as well as between healthy women and RA patients. The extension and flexion force improved in both groups after six weeks of hand exercise (p<0.01). Hand function improved in both groups (p<0.01). The RA group showed improvement in the results of the DASH questionnaire (p<0.05). The cross-sectional area of the EDC increased significantly in both groups. Conclusions: A new finger extension force measuring device has been developed which provides objective and reliable data on the extension force capacity of normal and dysfunctional hands and is sufficiently sensitive to evaluate the effects of hand exercise. US provide useful information about muscle architecture. A significant improvement of hand strength and hand function in RA patients was seen after six weeks of hand training, the improvement was even more pronounced after 12 weeks. Hand exercise is thus an effective intervention for RA patients, providing better strength and function.
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| 2. |
- Brorsson, Sofia, 1973-, et al.
(författare)
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Differences in muscle activity during hand-dexterity tasks between women with arthritis and a healthy reference group
- 2014
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Ingår i: BMC Musculoskeletal Disorders. - London, England : Springer Science and Business Media LLC. - 1471-2474. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Background: Impaired hand function is common in patients with arthritis and it affects performance of daily activities; thus, hand exercises are recommended. There is little information on the extent to which the disease affects activation of the flexor and extensor muscles during these hand-dexterity tasks. The purpose of this study was to compare muscle activation during such tasks in subjects with arthritis and in a healthy reference group. Methods: Muscle activation was measured in m. extensor digitorium communis (EDC) and in m. flexor carpi radialis (FCR) with surface electromyography (EMG) in women with rheumatoid arthritis (RA, n = 20), hand osteoarthritis (HOA, n = 16) and in a healthy reference group (n = 20) during the performance of four daily activity tasks and four hand exercises. Maximal voluntary isometric contraction (MVIC) was measured to enable intermuscular comparisons, and muscle activation is presented as %MVIC. Results: The arthritis group used a higher %MVIC than the reference group in both FCR and EDC when cutting with a pair of scissors, pulling up a zipper and-for the EDC-also when writing with a pen and using a key (p < 0.02). The exercise "rolling dough with flat hands" required the lowest %MVIC and may be less effective in improving muscle strength. Conclusions: Women with arthritis tend to use higher levels of muscle activation in daily tasks than healthy women, and wrist extensors and flexors appear to be equally affected. It is important that hand training programs reflect real-life situations and focus also on extensor strength.
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| 3. |
- Brorsson, Sofia, 1973-, et al.
(författare)
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Ultrasound evaluation in combination with finger extension force measurements of the forearm musculus extensor digitorum communis in healthy subjects
- 2008
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Ingår i: BMC Medical Imaging. - London : BioMed Central. - 1471-2342 .- 1471-2342. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background:The aim of this study was to evaluate the usefulness of an ultrasound-based method of examining extensor muscle architecture, especially the parameters important for force development. This paper presents the combination of two non-invasive methods for studying the extensor muscle architecture using ultrasound simultaneously with finger extension force measurements.Methods:M. extensor digitorum communis (EDC) was examined in 40 healthy subjects, 20 women and 20 men, aged 35-73 years. Ultrasound measurements were made in a relaxed position of the hand as well as in full contraction. Muscle cross-sectional area (CSA), pennation angle and contraction patterns were measured with ultrasound, and muscle volume and fascicle length were also estimated. Finger extension force was measured using a newly developed finger force measurement device.Results:The following muscle parameters were determined: CSA, circumference, thickness, pennation angles and changes in shape of the muscle CSA. The mean EDC volume in men was 28.3 cm3 and in women 16.6 cm3. The mean CSA was 2.54 cm2 for men and 1.84 cm2 for women. The mean pennation angle for men was 6.5° and for women 5.5°. The mean muscle thickness for men was 1.2 cm and for women 0.76 cm. The mean fascicle length for men was 7.3 cm and for women 5.0 cm. Significant differences were found between men and women regarding EDC volume (p < 0.001), CSA (p < 0.001), pennation angle (p < 0.05), muscle thickness (p < 0.001), fascicle length (p < 0.001) and finger force (p < 0.001). Changes in the shape of muscle architecture during contraction were more pronounced in men than women (p < 0.01). The mean finger extension force for men was 96.7 N and for women 39.6 N. Muscle parameters related to the extension force differed between men and women. For men the muscle volume and muscle CSA were related to extension force, while for women muscle thickness was related to the extension force.Conclusion:Ultrasound is a useful tool for studying muscle architectures in EDC. Muscle parameters of importance for force development were identified. Knowledge concerning the correlation between muscle dynamics and force is of importance for the development of new hand training programmes and rehabilitation after surgery.© 2008 Brorsson et al; licensee BioMed Central Ltd.
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