PMC

Muscle activation was measured with surface EMG in m. extensor digitorum communis and m. flexor carpi radialis in the dominant hand while performing four hand exercises and four daily tasks: (a) squeezing the putty, (b) rolling the putty with a flat hand, (c) finger extension, (d) isolated opposition, digits II–V (daily activities), (e) writing with a pen, (f) locking a door with a key, (g) cutting with scissors, and (h) pulling up a zip. Consent was obtained from individuals for publication of the images.

Muscle activation in m. flexor carpi radialis (FCR) and m. extensor digitorum communis (EDC) when performing daily activities and hand exercises for patients with reumatoid arthritis (RA), hand osteoarthritis (HOA) and a healthy reference group (RG) presented as percentage of maximal voluntary isometric contraction (%MVIC) (box plot shows median and range; * and º show outliers). a) Muscle activity in FCR radialis when performing daily tasks (left-right): writing with a pen, locking a door with a key, cutting with scissors and pulling up a zipper. b) Muscle activity in EDC when performing daily tasks (left-right): writing with a pen, locking a door with a key, cutting with scissors and pulling up a zipper. c) Muscle activity in FCR when performing hand exercises (left-right): squeezing the dough, rolling the dough with a flat hand, finger extension and isolated opposition digit II-V. d) Muscle activity in extensor digitorum communis when performing hand exercises (left-right): squeezing the dough, rolling the dough with a flat hand, finger extension and isolated opposition digit II-V.