Sensitivity of the foot in the flat and toe off positions.

The purpose of this study is to examine the differences in pressure sensitivity for areas of the foot in a toe-off position and with the feet on the ground. This data could provide a base for adapting the softness of different areas while designing footwear. 21 healthy subjects are asked to participate in a test where a researcher applies pressure with an advanced force gauge in 20 locations on the foot until the subject starts experiencing discomfort. Rigid shells of three sizes have been designed and 3D printed based on 3D foot scans. The test is performed in two positions: standing with load on the plantar surface and toe-off loading only the forefoot. The outcome is a pressure discomfort threshold map of the foot. Interestingly, in 16 locations the sensitivity was similar in both conditions (toe-off and complete foot on the ground). Especially, stretched areas showed increased sensitivity.