Design data for footwear: sweating distribution on the human foot
Purpose - The purpose of this paper is to provide footwear designers, manikin builders and thermo-physiological modellers with sweat distribution information for the human foot. Design/methodology/approach - Independent research from two laboratories, using different techniques, is brought together to describe sweat production of the foot. In total, 32 individuals were studied. One laboratory used running at two intensities in males and females, and measured sweat with absorbents placed inside the shoe. The other used ventilated sweat capsules on a passive, nude foot, with sweating evaluated during passive heating and incremental exercise to fatigue. Findings - Results from both laboratories are in agreement. Males secreted more than twice the volume of sweat produced by the females (p<0.01) at the same relative work rate. Both genders demonstrated a non-uniform sweat distribution, though this was less variable in females. Highest local sweat rates were observed from the medial ankles (p<0.01). The dorsal foot sweated substantially more than the plantar (sole) areas (p<0.01). Sweating on the plantar side of the foot was uniform. Wearing shoes limited the increase in sweat production with increasing load, while the sweat rate of uncovered feet kept increasing with work and thermal load. Practical implications - The observed variation in sweat rate across the foot shows that footwear design should follow the body mapping principle. Fabrics and materials with different properties can be used to improve comfort if applied to different foot surfaces. The data also demonstrate that foot models, whether physical (manikins) or mathematical, need to incorporate the observed variation across the foot to provide realistic simulation/testing of footwear. Originality/value - This paper provides comprehensive and novel data to be used in footwear design.