Civil Engineering Reference
In-Depth Information
25.3.1 Personality, Low Back Pain, and Spinal Loading
Of the few studies addressing the relationship between personality preferences and physical outcomes,
several involve low back pain reporting. Gatchel et al. (1995) scored subjects' responses on the hypochon-
driasis, depression, and hysteria scales of the MMPI. They found that those in the group having a chronic
disability due to low back pain had significantly higher mean scores on the hysteria scale than did those
persons who were not disabled. A similar finding was also reported in a large-scale study of aircraft
assembly employees (Bigos et al., 1991). Here, one's hysteria score was found to be a predictor variable
for the development of low back pain in workers who previously were uninjured. Bongers et al. (1993)
conducted an extensive literature review in an effort to evaluate the relationships between psychosocial
measures and the occurrence of MSDs. Among those factors positively correlated with the reporting of
back pain was Type A behavior and anxiety (which is analogous to neuroticism in the FFM).
One study specifically associated personality with loads on the lumbar spine. Marras et al. (2000)
studied the muscle activation patterns and spinal loads of subjects as they handled objects under both
“stressed” and “unstressed” lifting conditions. They also evaluated subjects' personalities using the
MBTI and found that increases in spinal loading during the stressed condition varied depending on
their personality types. Specifically, those with preferences toward introversion or intuition produced sig-
nificantly higher levels of spinal compression and lateral shear. This study suggests a possible pathway
between psychosocial stress and loading on the spine that may, in part, be influenced by one's personality
preferences.
25.3.2 Personality and Loading on the Upper Extremities
There are a few indications that personality traits may be related to differences in physical outcomes of
the upper extremities as well. Neck and shoulder muscle tension was reported by Salminen et al. (1991) to
be due to higher levels of muscle activity in those exhibiting Type A behavior. Further, Glasscock et al.
(2003), who also assessed Type A behavior, reported greater elbow flexor muscle activities among those
who were found to be Type A using the JAS. Together with the aforementioned low back studies, this
literature suggests that personality factors may play a role in determining the likelihood that one develops
musculoskeletal discomfort.
The research that does exist on a personality-physical outcome link is by no means all in agreement or
conclusive. A case in point relates to studies involving the extraversion-introversion traits. Scheier and
Carver (1987) theorized that the extraversion-introversion trait may be linked to a number of health-
related behaviors, but Bongers et al. (1993) concluded that there was not enough evidence in the litera-
ture to show a relationship between extraversion and back pain. The reason for this may be because
different assessment methods were used for measuring extraversion and introversion. For example,
the MMPI, the MBTI, the EPQ, and the FFM all include extraversion-introversion scales in their
assessments.
25.4 Conclusions
Researchers still are learning a great deal about factors related to musculoskeletal discomfort and the
causes of MSDs. However, the evidence is increasingly clear that the origins of MSDs are multifactorial
in nature. As conceptualized in Figure 25.1, important risk factors relate to both the physical and psy-
chosocial aspects of an individual's working environment, as well as to aspects of the individuals them-
selves. One of the many characteristics of individuals that can influence their (real or perceived) reactions
to the working environment is personality.
The study of human personality has created a multitude of theories aimed at describing one's behavior.
From these models arose a variety of inventories developed to assess personality factors relevant to that
theory. Some of the more commonly used models were described here. These have produced generally
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