In ergonomics, the biomechanical approach provides estimation of various me
chanical stresses acting on the body while a person manually handles an obj
ect. Although motion analysis systems are available for dynamic biomechanic
al analyses, the use of such systems are mostly performed in laboratory due
to high cost of the equipment and the expertise required in using them. In
dustrial ergonomists have limited access to dynamic biomechanical analyses.
This paper reports a dynamic simulation model developed for biomechanical
analyses of lifting activities performed in the sagittal plane. The model s
imulates the dynamic motion of lifting tasks for five body joints: the elbo
w, shoulder, hip, knee, and ankle. The inputs of the model include initial
and final joint postures; gender, weight, and height; weight of load; lifti
ng height; and container dimensions. In the output, the angular trajectorie
s of the five joints are predicted. The model without any video inputs pred
icts the motion patterns of the lift. Actual motion data were collected usi
ng 10 subjects in the laboratory for 360 lifts which included 12 lifting ta
sks in combination of two lifting heights, two container sizes, and three w
eights of load. Good results were found for the dynamic planar motion simul
ation model. The predicted motion pattern from the simulation closely resem
bles the observed motion pattern.