Title
The effects of shoulder load and pinch force on electromyographic activity and blood flow in the forearm during a pinch task
Author
Visser, B.
Nielsen, P.K.
de Kraker, H.
Smits, M.
Jensen, B.R.
Veeger, D.
van Dieën, J.H.
TNO Kwaliteit van Leven
KvL
Publication year
2006
Abstract
The object of the current study was to determine whether static contraction of proximal musculature has an effect on the blood flow more distally in the upper extremity. Static contractions of muscles in the neck shoulder region at three levels (relaxed, shoulders elevated and shoulders elevated loaded with 4.95 kg each) were combined with intermittent pinch forces at 0, 10 and 25% of the maximum voluntary contraction (MVC). Blood flow to the forearm was measured with Doppler ultrasound. Myoelectric activity of the forearm and neck-shoulder muscles was recorded to check for the workload levels. Across all levels of shoulder load, blood flow increased significantly with increasing pinch force (21% at 10% MVC and by 44% at 25% MVC). Blood flow was significantly affected by shoulder load, with the lowest blood flow at the highest shoulder load. Interactions of pinch force and shoulder load were not significant. The myoelectric activity of forearm muscles increased with increasing pinch force. The activation of the trapezius muscle decreased with increasing pinch force and increased with increasing shoulder load. The precise mechanisms accounting for the influence of shoulder load remains unclear. The results of this study indicate that shoulder load might influence blood flow to the forearm.
Subject
Health
Fysieke arbeidsbelasting
Bewegingsorganen
Handen armen
Bloedsomloop bloedvaten
Blood flow
Computer work
Electromyography
Upper extremity musculoskeletal disorders
Biomechanics
Blood
Electromyography
Musculoskeletal system
Musculoskeletal disorders
Ergonomics
Doppler echography
Finger
Forearm blood flow
Workload
Adult
Biomechanics
Blood Flow Velocity
Electromyography
Forearm
Humans
Male
Motor Activity
Muscle Contraction
Muscle, Skeletal
Pinch Strength
Shoulder
Torque
Upper Extremity
Weight-Bearing
To reference this document use:
http://resolver.tudelft.nl/uuid:acf248fb-0f17-4377-91f6-6fe5607624f7
DOI
https://doi.org/10.1080/00140130600901652
TNO identifier
239767
ISSN
0014-0139
Source
Ergonomics, 49 (15), 1627-1638
Document type
article