The field of biomechanics has undergone revolutionary changes in recent years. Early developments in the field focused mainly on phenomena at the level of the body, organs, and tissues, whereas recent technological developments make it possible to measure forces and displacements at cellular and molecular levels. In parallel with biochemical processes, mechanical or physical forces play important roles in biology at every level of organization: organism, organ, tissue, cell, and molecule. For example, the strength of skeletal muscles increases with regular physical exercise; heart and blood vessels are remodeled by elevated blood pressure; bone remodels in response to applied forces; cell migration depends on adhesion forces; and the cell cytoskeleton structure adjusts to the forces applied to the cell.