A hinged tool includes a first member; a second member pivotally connected to the first member at a pivot; and an optical fiber. The optical fiber is fixed to the first member at a load application region and fixed to at least one of the pivot and the second member at a location such that the optical fiber bends when the first member and the second member are pivoted with respect to one another. A method of using a hinged tool includes measuring fiber strain in an optical fiber fixed to the hinged tool, and determining at least one of tool strain applied to the hinged tool and a degree of pivoting of the hinged tool using the fiber strain.