A Biomechanical Analysis of Manual Materials Handling Tasks in Restricted Working Postures

Abstract

The U. S. Bureau of Mines has developed a biomechanical modeling system to examine the stresses on the lumbar spine when lifting in stooped and kneeling work postures utilized by low-seam underground coal miners. This system allows Bureau researchers to digitize two videotaped views (frontal and sagittal) of underground miners performing various lifting tasks under laboratory conditions. These points are then translated into a three-dimensional coordinate system, and a link man (developed from known anthropometry of the subject) is fitted to the 3-D coordinates. The centers of mass for the various links are calculated according to the body type (rotund, muscular, thin, or median) of the subject. Compression results were estimated using a linear programming internal/external load model. The location of the L₃ vertebral body center was calculated based upon anthropometric data and morphometric studies of the lumbar spine. Results of the compression and shear force analyses for restricted lifting postures are presented and discussed.

Get full access to this article

View all access options for this article.

References

Bobick

T. G.

(1987). Analyses of Materials-Handling Systems in Underground Low-Coal Mines. In Proceedings of Bureau of Mines Technology Transfer Seminar, Bureau of Mines Information Circular 9145 (pp. 13–20).

Chaffin

D. B.

Andersson

G. B. J.

(1984). Occupational Biomechanics. New York: John Wiley and Sons.

Dempster

W. T.

(1955). Space Requirements for the Seated Operator, WADC-TR-55–159, Aerospace Medical Research Laboratories, Ohio.

Gallagher

(1987). Back Strength and Lifting Capacity of Underground Miners. Proceedings of Bureau of Mines Technology Transfer Seminar, Bureau of Mines Information Circular 9145 (pp. 21–32).

Lavender

S. A.

Marras

W. S.

(1987). The Effects of Seam Height, Scaling Method, and Bar Weight Distribution on Scaling Effectiveness and Electromyographic Activity. In Proceedings of the Human Factors Society 31st Annual Meeting (pp. 471–475).

Marras

W. S.

Reilly

C. H.

(in press). Networks of Internal Trunk Loading Activities Under Controlled Trunk Motion Conditions. Spine, in press.

Schultz

A. B.

Andersson

G. B. J.

(1981). Analysis of Loads on the Lumbar Spine. Spine, 6(1): 76–82.

Schultz

A. B.

Andersson

G. B. J.

Ortengren

Haderspeck

Nachemson

, 1982. Loads on the Lumbar Spine: Validation of a Biomechanical Analysis by Measurement of Intradiskal Pressures and Myoelectric Signals. Journal of Bone and Joint Surgery, 64-A(5): 713–720.