Wrist extensor muscle activity is less task-dependent than wrist flexor muscle activity while simultaneously performing moderate-to-high handgrip and wrist forces

Wrist splints are commonly prescribed to limit wrist motion and provide support at night and during inactive periods but are often used in the workplace. In theory, splinting the wrist should reduce wrist extensor muscle activity by stabilizing the joint and reducing the need for co-contraction to maintain posture. Ten healthy volunteers underwent a series of 24 10-s gripping trials with surface electromyography on 6 forearm muscles. Trials were randomized between splinted and nonsplinted conditions with three wrist postures (30° flexion, neutral, and 30° extension) and four grip efforts. Custom-made Plexiglas splints were taped to the dorsum of the hand and wrist. It was found that when simply holding the dynamometer, use of a splint led to a small (<1% MVE) but significant reduction in activity for all flexor muscles and extensor carpi radialis (all activity <4% maximum). At maximal grip, extensor muscle activity was significantly increased with the splints by 7.9–23.9% MVE. These data indicate that splinting at low-to-moderate grip forces may act to support the wrist against external loading, but appears counterproductive when exerting maximal forces. Wrist bracing should be limited to periods of no to light activity and avoided during tasks that require heavy efforts.

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Reciprocal effect of single corticomotoneuronal cells on wrist extensor and flexor muscle activity in the primate

Brain Research ◽

10.1016/0006-8993(82)91043-5 ◽

1982 ◽

Vol 247 (1) ◽

pp. 164-168 ◽

Cited By ~ 16

Author(s):

Paul D. Cheney ◽

Richard Kasser ◽

James Holsapple

Keyword(s):

Muscle Activity ◽

Flexor Muscle ◽

Reciprocal Effect ◽

Wrist Extensor ◽

Corticomotoneuronal Cells

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The Most Effective Number of Elastic Taping Applications on the Muscle Activity and Maximum Peak of the Wrist Extensor Muscle in Patients with Stroke

Journal of the Ergonomics Society of Korea ◽

10.5143/jesk.2014.33.6.533 ◽

2014 ◽

Vol 33 (6) ◽

pp. 533-541 ◽

Cited By ~ 1

Author(s):

Ju Chul Cho ◽

Byoung Kwon Lee ◽

Seung Chul Chon

Keyword(s):

Muscle Activity ◽

Extensor Muscle ◽

Effective Number ◽

Maximum Peak ◽

Wrist Extensor

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Individual Differences in the Activity of Dominant Forearm Muscles during VDT Work

Proceedings of the Human Factors and Ergonomics Society Annual Meeting ◽

10.1177/154193129503901316 ◽

1995 ◽

Vol 39 (13) ◽

pp. 926-930 ◽

Cited By ~ 1

Author(s):

Rajendra D Paul ◽

Krishna Menon ◽

Chandra Nair

Keyword(s):

Muscle Activity ◽

Role Play ◽

Employee Training ◽

Extensor Muscle ◽

Flexor Muscle ◽

Work Activity ◽

Forearm Muscles ◽

Analysis Of Results ◽

Forearm Muscle ◽

Subject Differences

In two studies on VDT work, activity of dominant forearm muscles was measured using surface electromyography. In the first study (n = 12), subjects used only a keyboard; whereas in the second study (n = 8), subjects used both keyboard and mouse. In both studies, analysis of results indicated that inter-subject differences in forearm muscle effort were significantly different (p < 0.05). In the first study, the minimum-to-maximum ratio for average extensor muscle activity was 1:3.7. In the second study, the minimum-to-maximum ratio was 1:2.2 for the flexor muscle activity and 1:3.7 for the extensor muscle activity. These results support the notion of differences in individual workstyles proposed by Feuerstein (1995). Individual typing styles play an important role play an important role in the stress on forearm muscles during VDT work and should be included in employee training protocols.

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