Engineering Anthropometry - Fundamentals and Assessment Tools for Occupational Ergonomics - page 203

Preferred work areas of the hands and feet are in front of the body, within curved envelopes that reflect
the mobility of the forearm in the elbow joint, or of the total arm in the shoulder joint, of the lower leg in
the knee joint, and of the total leg in the hip joint. Thus, these envelopes may be described as (partial)
spheres around the presumed locations of the body joints. However, the preferred ranges within the poss-
ible motion zones differ depending on whether the main requirements are strength, or speed, or accuracy,
or vision — as discussed in some detail, by Kroemer et al. (1997, 2001). Thus, there is not one reach
envelope, but different preferred envelopes, depending on the task.
For each job situation, the ergonomic designer determines the dominant requirements of the task, for
example, whether the operator

. Works while sitting or walking (standing)
. Performs wide-ranging or specialized work

FIGURE 9.5 Maximal displacements in body joints. (From Kroemer et al., Engineering Physiology. Bases of Human
Factors Ergonomics, 3rd ed., Van Nostraud Reinhold — John Wiley & Sons, New York, NY 1997. With permission.)

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