Modelling Work Tasks and the Bending Capabilities of Subjects

Abstract

The extent to which subjects can bend over while carrying out repetitive task, as
measured by the postural angle, θ, in degree in relation to work space, without developing
lower back pain (LBP) that is caused by over exertion of the thora-columbar force has been
ascertained with the aid of anatomical model developed in this study. A free body diagram
(FBD) of the human anatomical system was developed and used to carry out a biokinetic
analysis in order to determine the theoretical relationship between the force erector muscle
and the anthropometric variables. The model was fitted into anthropometric data of Nigeria
population presented in percentile values. Our results suggest that the magnitude of erector
muscle force is to a large extent determined by the body weight (WB) and trunk angle, θ.
And that the reaction forces generated at the hip can be of the order of ten raised to power 3
of the body weight (WB). The utility of the research outcome appears appealing especially
to Industrial Engineers who may find it needful for work space and jobs design.