(bio=life + machine) is the application of the principles of mechanics
and physics to measure the forces exerted by and upon living forms.
Human Factors is principally concerned with occupational biomechanics
which is the application of these principles to the measurement
of forces exerted by and upon the human body during the performance
of work. These measurements are used to determine physical work
performance tolerances with the goal of maximizing work performance
while protecting worker occupational health and safety.
application of the principles of mechanics and lever systems to
the human body requires the use of anthropometric data, critical
data being the distance/length of body levers (bones) between joints.
subject lifting an object (above)
subject lifting the same object
from Tichauer, E. R., The Biomechanical Basis of Ergonomics:
Anatomy Applied to the Design of Work Stations, New
York: John Wiley & Sons, 1978)
variability in physical size (static anthropometry) and physical
strength (dynamic anthropometry) is also important in biomechanics
with respect to the worker population in terms of gender, age, and
ethnicity. Above is an example of biomechanical calculations
of the forces acting upon the lumbosacral joint during a lifting
task. Note, the forces differ between males and females because
of gender dependent differences in body segment proportions. That
is, the majority of females have shorter legs and longer torsos
than males (Tichauer, 1978, op.cit).