When axial loads are not parallel with the material direction, the asymmetrical forces cause polarization and stress-generated potentials. A moving current is formed which results in an electrical magnetic field. In 1896 the relationship of bone growth to pressure was defined as Wolff's Law. The form of a bone being given, the bone elements place or displace themselves in the direction of the functional pressure and increase of decrease their mass to reflect the amount of pressure. This law states that bone will remodel to stress placed upon it.
Abnormal posture causes mechanical force to be transformed into electrical energy.
It is now evident that mechanical energy is being transduced into electrical energy to direct and maintain the organization of cellular life. A charge separation occurs on bone under an applied load. Bone is a piezoelectrical material which has the property of electric polarization under an applied load. There is a reciprocal relationship of bone mechanically distorting in the presence of an electrical field. Under applied physical stress there is bond distortion at the molecular level which produces a dipole moment and results in an electric field inside the bone.