3.3 Experimental procedure
Experiments were performed lifting at the lifting machine,
andEMGand ECG were adhered to the body of subjects.
Two different weights of 10 kg and 25 kg were by turns set
at the lifting machine by means of filling pebbles into bags
and placing on the plastic box. These two weights are the
weight of objects that the workers of Mando Machinery
Corporation Ltd. usually do their jobs in relation to
manual material handling. Information on the weights
were not given to the subjects. The method of NIOSH
Lifting Equation in 1991 was applied to the experiment of
lifting. Investigation on horizontal, vertical, frequency,
distance, asymmetric, and coupling at the workplace were
done and applied to the experiment. In the case ofCM,it is
‘‘fair’’ due to the plastic box having the grip.In the case of
AM, the experiment was performed without an asymmetrical
angle.
The variable of vertical distance used in the experiment
was fixed at 2080 cm. The variable of working frequency
was also fixed at 2 times per minute. Other variables are
horizontal distance of 35 cm&55 cmand weight of 10 kg
& 25 kg. Vertical distance and working frequency were
fixed, because horizontal distance and weight turned out
to be the most influential factors of NIOSH Lifting
Fig. 2 Experiment Design Equation in past experimental results(Yang [19]). Exper-