A small, light and inexpensive pocket flicker (P. F.) apparatus for measuring fatigue was designed, fabricated and tested. The apparatus, being composed of a light emitting diode and a variable resistor with a scale, is so compact that it can be carried in a shirt pocket. Thus, critical fusion frequency (CFF) values can be easily determined at a working place and the load involved is small when compared to other physical fatigue measurements and earlier CFF apparatuses. Moreover, the apparatus is so inexpensive that it can be widely used. To compare the performance of the P. F. apparatus with earlier apparatuses, the following experiments were performed. CFF values were measured at the same time with the pocket type apparatus, blinking type apparatus and sector type apparatus and the results were compared. The subjects were 13 males and 5 females with their age ranging from 21 to 52 years. The total number of measurments was 132. The CFF values measured with these three apparatuses showed a significant correlation. The correlation coefficient between the CFF values measured with the sector type apparatus and blinking type apparatus was high, but the slope of the regression line was not one. Hence, in comparing the values measured with another apparatus, we should be aware of the differences between these data. The correlation coefficients between the CFF values measured with P. F. apparatus and with sector type apparatus or blinking type apparatus were not higher than those between the CFF values measured with sector type apparatus and blinking type apparatus. As the standard deviation of the CFF values measured with the P. F. apparatus was higher than that calculated from other apparatuses, the CFF values measured with the P. F. apparatus are less accurate than those measured by other apparatuses. The results of these experiments suggest that the P. F. apparatus is an effective tool for measurement of fatigue. However, some problems (durability and precision) must be resolved before its practical use and therefore improvements should be made by further experiments.
ASJC Scopus subject areas
- Public Health, Environmental and Occupational Health