According to the nature of low back pain that is not impacted by
the study setting, the questionnaire which included the details as
described above was pretested among 50 rubber tappers in
Songkhla Province. After the pretest, the questionnaires were corrected
for comprehensibility of the questions before administering
the questionnaires to the target participants in the study area.
In the actual data collection, the selected participants were first
screened for eligibility. A physical examination procedure used for
screening was adopted from the American College of Physicians
and the American Pain Society guideline (Chou et al., 2007). They
included observation and regional back examination, neurologic
screening, straight-leg raising test and sitting knee extension test.
After the physical examination, the body discomfort chart, an
instrument which had been shown to provide a valid measure of
body discomfort, and an analog pain rating scale (Borg Scale) were
completed by all subjects. The items included the pattern and
intensity of pain, if any, in any body region during the previous
three months. After that, a face-to-face interview using the structured
questionnaire was performed. The participants were visited
at their rubber plantations and the working posture was recorded
using a video recorder (SONY DCR-SR88) in a separate occasion.