Reliability and Validity of Questionnaire for Assessing Physical Workloads

Lee, Dongjun; Kang, Dongmug; Koh, Sang Baek; Kim, Jungwon; Jang, Junho; Kim, Jongeun; Cho, Byungmann; Lee, Suill

Abstract

OBJECTIVES
The aims of the study were to make a questionnaire for assessing physical workloads and to evaluate its reliability and validity.
METHODS
A total of 220 workers (foundry workers 30, large vehicle assemblers 30, shipyard workers 75, and automobile manufacturers 80) completed a self-administered questionnaire and took examinations for physical work capacity and working heart rate. We excluded data with insufficient responses or incorrect physical work capacity and working heart rate. Finally, the data of 154 workers (70.0%) were used for our study. In order to evaluate the reliability and validity of the questionnaire, we used statistical analyses including the scaling assumption test and a comparison with the objective tool for physical workload which was evaluated by working energy expenditure.
RESULTS
The items of the questionnaire in the same categories had close distribution in the evaluation of the scaling assumption. The item internal consistency was 0.41-0.73 for posture factor, and 0.62-0.79 for non-posture factor. The item discriminate validity was 100%. Cronbach's alphacoefficient of the total items was 0.73 (0.58 for posture factor and 0.74 for nonposture factor). In the correlation between working energy expenditure and questions, general physical activity (p=0.008), proportion of the workday with hands above shoulder (p=0.002), proportion of the workday with trunk bent (p=0.028), proportion of the workday with awkward posture (p=0.048), sweating after work (p=0.006), total scales (p=0.003) and Borg scale (p=0.011) all had statistical significance.
CONCLUSIONS
Our questionnaire for assessing physical workloads demonstrated statistically significant reliability and validity. But the questions for the proportions of the workday with sitting work posture and with static posture should be modified via a larger study.