COMPARISON BETWEEN THE VISUAL ANALOG SCALE (VAS) AND THE CATEGORY RATIO SCALE (CR-10) FOR THE EVALUATION OF LEG EXERTION

Perceptual ratings given on the Visual Analogue Scale (VAS) and the Category Ratio Scale (CR-10) were compared in 24 healthy male volunteers (18-39 years) subjected to an exercise test using a bicycle ergometer. Ratings of leg exertion were made by means of the CR-10, the VAS and, as a complementary measure, the method of free magnitude estimation (ME). Blood lactate levels (BL) and heart rates (HR) were used as correlates to sensory perception. The correlation between the CR-10 ratings and BL at 180 W were .59 (p < .01), and between VAS ratings and BL .45 (p < .05). The corresponding correlations with HR were .64 (p < 0.01) and .58 (p < 0.01), respectively. No significant correlation was found for ME. It was concluded that both the CR-10 and the VAS scales were found to be useful for the psychophysical estimation of perceptual intensities. The CR-10 scale appeared to be slightly more efficient than the VAS and both these methods much better than ME. The advantage of the CR-10 scale might be due to a greater ability to discriminate at high intensity levels.