Spinal Forces During Symmetric Lifting in Four Postures.
Paper in XIII Int'l Congress Biomech Book of Abstracts Univ of Western Australia Pp 228-230 :228-230
The height of an underground coal mine is generally determined by the thickness of the mineral seam. In many cases, the seam is less than 1.2 M in height. Workers in coal mines are often required to lift heavy materials in severely restricted postures. Two common postures used for lifting are stooping or kneeling on two knees. Demands on the supporting structures of the spinal column are likely to differ considerably in these postures compared to unrestricted lifting situations. Thus, traditional recommendations for lifting in unrestricted postures may not be applicable to the underground mining environment. A recent electromyogram-driven model has been developed that is sensitive to changes in muscular recruitment and thus should be useful in analysing work performed in restricted postures. Previous U.S. Bureau of Mines studies have used this model to examine spinal forces in kneeling and stooping postures under a 1.2-M-high ceiling for both symmetric and asymmetric lifts. These studies found that compression was greatest in kneeling, and shear forces were greatest while stooped. The present study examines stooping under a higher roof and standing, in addition to the postures examined in the previous studies. See also op 7-92.
Paper in XIII Int'l Congress Biomech. Book of Abstracts. Univ. of Western Australia, Pp 228-230