Load distribution to minimise pressure-related pain on foot: a model

The optimal force distribution to minimise pain or discomfort at the foot-shoe interface is still not known. Most shoe-related products attempt to distribute the load uniformly without much consideration to the bony and soft tissue regions. An experiment was conducted to first determine the pressure pain threshold (PPT) and tissue deformation on the plantar surface of the foot. Circular probes of areas 0.5, 1.0 and 2.0cm(2) at indentation speeds of 0.5, 1 and 2mm/s showed that PPT depends on the location stimulated, area of stimulation and the indentation speed. The results also showed that tissue stiffness is quite low for small deformations (<4mm), but significantly higher at large deformations (>4mm). The stiffness at the larger deformation region was positively correlated with PPT (r=0.63, p