ANTHROPOMETRY - Biomechanics and Motor Control of Human Movement - page 94

Figure 4.6 A 21-marker, 14-segment model to estimate the 3D center of mass of the
total body in balance control experiments. Four trunk segments were necessary to track
the internal mass shifts of the thoracic/lumbar volumes.

noting that most of the segments are fairly rigid segments (head, pelvis,
upper and lower limbs). However, the trunk is not that rigid, and it required
four separate segments to achieve a reliable estimate, mainly because these
trunk segments undergo internal mass shifts due to respiratory and cardiac
functions. The validity of any COM estimate can be checked with the equation
for the inverted pendulum model during the movement: COP ·

C OM (Winter et al., 1998). COP is the center of pressure recorded from
force plate data, C OM is the horizontal acceleration of COM in either the

− COM =− K