The motion of an isolated skyrmion in a two dimensional film can be described by a modified version of Newton’s equation which tracks the coordinate evolution of the skyrmion's center. For forces too weak to alter the skyrmion profile significantly, a symmetry analysis imposing translational and rotational invariance suggests the following Thiele-equation of motion [Everschor 2011,Clarke 2008,Thiele 1973,Iwasaki 2013]: