The effects of position and size of drywall on the physical demands for installers

摘要

Abstract The present study utilized an integrated biomechanical modeling approach that was previouslydeveloped by the researchers to investigate the effects of position and size of drywall on the physicaldemands for drywall installers. If the drywall sheets were stored vertically instead of flat, it reduced therequired muscle contraction forces and joint reaction forces at the low back and shoulder approximately 8%on average during drywall installation. In particular, the L4/L5 disc compression forces and the absolutevalues of L4/L5 anterior-posterior shear forces decreased 6.1% and 8.5%, respectively, and at the shoulderduring lifting the forces of rotator cuff muscles decreased 9.8%, and the coracohumeral ligament forcesdecreased 12.8%. The reaction forces at both the GH (glenohumeral) and SC (sternoclavicular) joints werereduced 7.2% and 3.6%, respectively. The larger size (e.g., 4x12 and 4x16) of drywall sheets increased thephysical burden for the installers tremendously and could expose them to a higher risk of musculoskeletalinjuries and disorders. In some simulations the average low back lateral shear forces increased to 1675 Nand 2152 N, respectively. These forces are well above the 1000 N recommended for a single lift. Theseresults indicated that it would be physically too difficult or even impossible for one person alone to liftbigger and heavier drywall sheets. Therefore, sound engineering (e.g., lifting tables) and/or administrative(e.g., two-person team work) solutions to handling oversized drywall sheets are strongly recommended.