A model for the perception of surface pressure on human foot

The psychophysical relationship between the magnitude of pressure on thirteen test locations of twenty healthy subjects' feet with four probe areas at three indentation speeds and the corresponding perceived sensations were analyzed. The dependency of pressure pain thresholds (PPT) on area, A, and speed, v, can be mathematically modeled in the form, PPTi = [ai + bLn(v)]Aβi = 1,2…13 where β and b are constants and are dependent on location and gender, and ai is a constant highly correlated with foot tissue stiffness. The relationship between the sensory intensity to pressure magnitude appears to follow a modified Stevens' power law with power exponents less than 1.0 and consistent across the 13 test locations with a mean of 0.82 and a range from 0.67 to 0.98. This particular model helps to understand the sensation of pressure threshold and its impact in the design of consumer products. ► We mathematically model the dependency of pressure pain threshold (PPT) on stimulus area (A), speed (v) and locations of human foot for males and females. ► The model is of the form PPTi = [ai + bLn(v)]Aβ location i = 1,2…13 where ai, b and β are constants. ► The relationship between the sensory intensity and pressure follows the form of a modified Stevens' power law. ► Sensory intensity increases with pressure, but, is negatively accelerated.