Leung, W.S., Chan, C.H. and He, J.F., The Hong Kong Polytechnic University, Hong Kong SAR
Fatigue is a common phenomenon among working individuals. The Swedish Occupational Fatigue Inventory (SOFI) is designed to tap on the five latent factors of fatigue: lack of energy, physical exertion, physical discomfort, lack of motivation and sleepiness. This study was to adopt the SOFI for use in Chinese population and to establish its construct validity and reliability. A qualified translator was recruited to translate the Chinese version SOFI. Content validity was established with 12 bilingual and 7 professional experts. The translated SOFI was administered to 104 sedentary workers in two occasions with 1 hour apart. Most of them were female and half of them worked 4 hours or more on computer daily. The five SOFI latent factors of the Chinese version were found to be relevant and representative to work-related perceived fatigue. Exploratory factor analysis revealed a five-factor solution which accounted for 78.2% of the total variance; 23 out of the 25 expressions were loaded onto their original latent factors. Cronbach's alpha for items within the five factor scales varied between 0.88 and 0.95. Test-retest reliability was satisfactory (ICC = 0.69 to 0.83). The SOFI profile suggested a more severe fatigue in mental-related factors than physical-related factors. Individuals worked 4 hours or more reported fatigue significantly higher than those worked less than 4 hours (p=0.003 to 0.037). Those with eye discomfort reported significantly higher rating in lack of energy (p=0.05). The result indicated that the Chinese version SOFI was valid and reliable for measuring fatigue in Chinese working population. The high fatigue phenomenon would be the result of tedious work engagement on the vigilance sedentary task. Report on eye discomfort suggested excessive visual stimulation attributed to fatigue of the cortical system.