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Open Access Research article

Differences in muscle activity during hand-dexterity tasks between women with arthritis and a healthy reference group

Sofia Brorsson12*, Anna Nilsdotter3, Carina Thorstensson45 and Ann Bremander167

  • * Corresponding author: Sofia Brorsson sbo@du.se

Author Affiliations

1 Health and Welfare, Dala Sports Academy, Dalarna University, SE-781 88 Falun, Sweden

2 School of Business and Engineering, Department of Exercise Physiology, Biomechanics and Health, Halmstad University, Halmstad, Sweden

3 Department of Research and Education, Halmstad County Hospital, Halmstad, Sweden

4 Department of Clinical Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden

5 Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden

6 Department of Clinical Sciences, Lund, Section of Rheumatology, Lund University, Lund, Sweden

7 Research and Development Center, Spenshult, Oskarstrom, Sweden

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BMC Musculoskeletal Disorders 2014, 15:154  doi:10.1186/1471-2474-15-154

Published: 15 May 2014

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.

Keywords:
Muscle activation; Muscle extension force; Flexion force; Female; Daily activities