Cell migration is an essential part of embryogenesis, wound healing and immuno-logical responses. As cells migrate forward, they exert forces against their extracellular matrices through matrix ligands such as integrins. The forces depend upon the cell-substratum adhesion strength  and the ability of integrins to bind to the cytoskeleton. The forces also vary according to cell speed; faster moving cells exert less force than slower moving cells . Determining the traction forces exerted by cells and how these forces can be modified has important implications in tissue engineering where enhanced migration speed and traction induced reorganization of the extracellular matrix can have a profound effect on cell invasion.