The Effect of Flooring Surface Compliance on Plantar Pressures and Discomfort During Prolonged Standing.

Abstract

Prolonged standing is common in the workplace, and is a cause of pain and discomfort in the feet, legs, and lower back. Anti-fatigue mats are often used in industry to reduce discomfort resulting from prolonged standing. However, there are currently no means for predicting the effectiveness of a particular mat in mitigating discomfort, and there is little understanding of how discomfort develops during prolonged standing. The main objective of this research was to investigate the cause of discomfort during prolonged standing, and the role of mats in reducing discomfort.

The effect of flooring material properties on discomfort and behavior was investigated during four-hour periods of standing. Touch sensitivity of the foot was also measured before and after standing to test for changes in sensitivity. Plantar pressure was investigated as a potential mechanism for discomfort during standing by testing the pain-pressure threshold at different levels of constant pressures on the foot. Finally, the effects of flooring and shoes on plantar pressure were studied.

During prolonged standing, mats reduced discomfort when compared to a hard floor, but no differences in discomfort were observed among mats. During standing, weight-shifting was correlated to discomfort and demonstrated lower statistical variance than subjective ratings of discomfort. These findings suggest that weight-shifting may offer a more sensitive measurement for discomfort than subjective ratings. Finally, as a result of prolonged standing, touch sensitivity of the feet increased, suggesting potential unintended bias in clinical touch sensitivity testing.

During pain-pressure threshold testing, elevated levels of constant plantar pressure were associated with an earlier onset of pain, indicating that plantar pressure is a mechanism that contributes discomfort. Flooring significantly affected plantar pressure during barefoot standing and walking, but when shoes were worn the effects of flooring on pressure were very small or not significant. This suggests that for reducing plantar pressure, attention should be focused on the design of footwear rather than the design of mats. Because flooring does not affect plantar pressure, mats must reduce discomfort through some other unknown mechanism.