ANTHROPOMETRY - Biomechanics and Motor Control of Human Movement - page 87

Figure 4.3 Location of the center of mass of a body segment relative to the distributed

mass.

m i = d i V i

where d i = density of i th section

V i = volume of i th section

If the density d is assumed to be uniform over the segment, then m i = dV i

and:

n

M = d V i (4.4)

i = 1

The center of mass is such that it must create the same net gravitational
moment of force about any point along the segment axis as did the original
distributed mass. Consider the center of mass to be located a distance x from
the left edge of the segment,

n

Mx = m i x i

i = 1

n

1
M

x = m i x i (4.5)

=

i 1

We can now represent the complex distributed mass by a single mass M
located at a distance x from one end of the segment.

Example 4.2. From the anthropometric data in Table 4.1 calculate the coor-
dinates of the center of mass of the foot and the thigh given the following