Quantifying precision and speed effects on muscle loading and rest in an occupational hand transfer task [An article from: International Journal of Industrial Ergonomics]

This digital document is a journal article from International Journal of Industrial Ergonomics, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Musculoskeletal disorders of the upper limb are common among semi-automated occupational hand transfer tasks. Ten healthy adults were recruited (five males, five females). Surface electromyography (EMG) was collected from eight muscles of the right arm: Upper trapezius, supraspinatus, infraspinatus, brachioradialis, extensor carpi radialis, extensor carpi ulnaris, extensor digitorum indicis, and flexor digitorum superficialis. The task consisted of a repetitive transfer of a 1.8-kg part at 2, 3, and 5s cycle times (CTs), using power and chuck grips, and under precision and non-precision conditions. EMG was quantified using the amplitude probability distribution function (muscle loading) and gaps analyses (muscle rest). For all muscles, static (tenth percentile APDF) loading exceeded 1% and the muscle rest from gaps was below 10% at 2 and 3s CT. Precision increased loading in forearm muscles, and increased perceived difficulty (p