Citation

Ferguson SA, Marras WS. Int. J. Ind. Ergonomics 1992; 10(3): 207-215.

Copyright

(Copyright © 1992, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

The objective of this study was to quantify velocity coupling, which was operationally defined as simultaneous trunk motion in two or three planes of the body. Velocity coupling was measured as the percentage of time the velocity was above a given percentage of maximum voluntary velocity in two or three planes. Four typesvelocity coupling were quantified: sagittal/transverse (S/T), sagittal/frontal (S/F), transverse/frontal (T/F), and sagittal/transverse/frontal (S/T/F). These types of velocity coupling were quantified as a function of seven task asymmetries and two task weights. The results showed that the three types of two-way velocity coupling had different response patterns to increased taskasymmetries. The total percentage of two-way velocity coupling significantly increased as task asymmetry increased from 0 to 30 degrees. The percentage of S/T velocity coupling decreased as task weight increased. It was also found that twice as much velocity coupling occurred at lifting task asymmetries beyond 120 degrees as compared to symmetric lifts. The effects of velocity coupling on strength and spinal loading are discussed.