Walking patterns and micromechanical load-transfer properties of human bone

Abstract

When the foot of a person walking is lifted off the floor, electrical charge accumulates on the sole of the shoe or foot, which is then transferred to the body. When the foot is put back on the floor, the body uncharges. The combined effects of these charges induced stresses, in additional to the mechanical stresses due to walking cycle, on the micromechanical load-transfer properties of tibia bone (idealised as a piezoelectric assembly) are studied here using Discrete Element Method simulations. The study shows that the difference in normal walking patterns alone do not significantly affect the load-transfer properties of bone. Human bone is naturally versatile enough to regulate the load transfer for normal walking styles. However, the variations in the charge generated from the footwear seem to influence the load-transfer properties of bone, in particular, during the beginning stages of walking. This influence diminishes at longer periods of walking. Though more research is required, the current study is a step towards understanding the complexities of the stress distribution at micro scale in human bones due to walking.