손 위치 및 외부 부하에 따른 전신 불편도 예측

Abstract

Objective: The purpose of this study is to develop linear models for predicting whole body discomfort and a new external load classification scheme depending upon hand position and external load.BR Background: Although quantification of whole body discomfort is useful for assessing physical workload, study on whole body discomfort is seldom found. The classification schemes of external load adopted in the existing posture classification methods such as OWAS, RULA, REBA etc. reflect just quantity of external load without considering their locations in the real work postures, which results in inaccurate work stress.BR Method: An experiment for measuring whole body discomfort was conducted, in which hand position and external load were used as independent variables. The hand position was determined by using percentages of shoulder height and arm distance. Fifteen healthy male college students without histories of musculoskeletal disorders participated in the experiment, whose demographic data are as follows: Age - 21.3 ± 1.80 years; Stature - 175.3 ± 5.88cm; Body weight - 75.5 ± 12.31kg.BR Results: ANOVA revealed that hand position, i.e. hand vertical height and horizontal distance, external load and their interaction effects are statistically significant on the whole body discomfort at α = 0.1 or 0.01. The effect of external load is the highest, followed by hand horizontal distance, and vertical height. Based on the experimental results, three types of linear models predicting whole body discomfort were proposed, which was classified by independent variables used in the models: hand position and external; angles of joint motions measured for experimental postures; and ROM transformed ratios for angles of joint motions. A new classification scheme of external load reflecting quantity of external load as well as its position was also developed.BR Conclusion: The study developed three linear modes for predicting whole body discomfort and a new classification scheme of external load.BR Application: The results of this study are useful for predicting whole body discomfort depending on hand position and external load, and for more precisely assessing work load according to external load.