Purpose: To test if the cause of loss of stability when wearing footwear was due to the influence of the shoe on proprioception - the sense of position and orientation of the plantar surface relative to the support surface.  This proprioceptive sense was termed "foot position awareness".

Synopsis: Subjects of younger and older age cohorts were tested for foot position awareness barefoot and when wearing shoes.  Subjects estimated surface slope when bearing weight based on a ratio scale.  The psychophysical function when estimating slope was close to unity for young subjects when barefoot, but significantly lower with older barefoot subjects.  It was also lower for both younger and older subjects with shoes.

Significance: This report suggests that young barefoot subjects use SA II mechanoreceptors for foot position sense when barefoot.  Older subjects use muscle receptors in foot position judgement when both barefoot and older presumably due to SA II receptor decline. This was the first report to suggest significant SA II receptor decline at the plantar surface with age.  It was also the first report to suggest that tactile receptors are used for proprioceptive sense with report to locomotion.