title: Differences in muscle activity during hand-dexterity tasks between women with arthritis and a healthy reference group.
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.
authors.affiliation: Health and Welfare, Dala Sports Academy, Dalarna University, SE-781 88 Falun, Sweden. sbo@du.se.
authors.forename: Sofia
authors.initials: S
authors.lastname: Brorsson
authors.forename: Anna
authors.initials: A
authors.lastname: Nilsdotter
authors.forename: Carina
authors.initials: C
authors.lastname: Thorstensson
authors.forename: Ann
authors.initials: A
authors.lastname: Bremander
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000503:physiopathology*; D004576:Electromyography; D015444:Exercise; D005260:Female; D006225:Hand / Q000503:physiopathology*; D018737:Hand Strength; D006801:Humans; D007537:Isometric Contraction; D008875:Middle Aged; D009068:Movement; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000503:physiopathology*; D010003:Osteoarthritis / Q000503:physiopathology*; D010044:Outpatient Clinics, Hospital