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Functional measurements and mobility restriction (from 3D to 4D scanning) 191

Lockhart and Bensel (1977) carried out similar studies for military clothing protec-
tive against cold climate and Gregoire et al. (1985) for protective suits against chem-
ical and biological warfare agents. The variables in the studies, among others, were
mobility, speed of movement, and coordination. These were examined in general per-
formance tests: For example, how deep the subjects can bend forward, and what dis-
tance they have covered after five steps. Alexander and Laubach (1973) examined the
arm reach of air force pilots in clothing protective against cold climate. The test setup
was modeled on the working environment of the pilots. They were sitting and had to
complete different reaches in a modified pegboard test. Alongside military clothing,
such analyses are especially carried out in the area of fire-resistant clothing (see
Fig. 7.16 on the right) (Son et al., 2013, 2014; Huck, 1988, 1991; Adams, 2000;
Graveling and Hanson, 2000; Coca et al., 2008, 2010; Son and Xia, 2010). Beginning
with Huck (1988) up until Son et al. (2014), the methods are comparable. The majority
of the mobility was quantified by analog devices such as goniometer, flexometer and
meter. Son and Xia (2010) used a motion capture system for the analysis of the mobil-
ity of the subjects. In principle, quality standards must be complied with for all ergo-
nomic analyses. Hsiao and Halperin (1998) established a six step program:
Determination of the relevant body dimensions:
1. Determination of the target group (sex, age, and profession)
2. Selection of the number of subjects (cost-benefit)
3. Data collection as a basis for the statistical evaluation
4. Calculation of specific dimensional changes
5. Implementation of the necessary adjustments to the clothing products
This guarantees solid data for the development of ergonomic products and a practice-
oriented use of anthropometric data. The measurement of the range of movement is
considered as a recognized method, and the results are considered as objective and
quantifiable.
Analog methods, however, do have the disadvantage of being very laborious and
prone to mistakes. Two persons are necessary for anthropometric measurement. One
measures the subject, and the other notes the results. The accuracy of the measure-
ments depends highly on the measurer (Kouchi, 2014). The manual recording of data
contains the risk for transfer errors. Landmarks that are used for different measure-
ments must be marked consistently. The time required, depending on the number
of measurements, is not insignificant and can possibly be stressful for the subjects.
This is because the survey is carried out on an unclothed body (in underwear) and
requires a close proximity to the subject. Especially dimensions such as crotch length
are usually perceived as rather uncomfortable.
Partially in studies, large differences were seen between the results of measure-
ments of different measurers (interobserver error) (Goodwin et al., 1992; Kouchi,
2014). Here, reproducible methods must be developed so that the performers achieve
a consistent identification of the anatomical landmarks and use of the anthropometric
devices. Three-dimensional scanner systems in combination with semiautomatic mea-
suring software reduce said sources of errors. For this reason, 3-D body scanners have
been used in various scientific works (see Chapter 6).