Abstract Relativistic quark-antiquark system in the vacuum background field is considered in the proper-time path-integral formalism. Dynamics is given by the Wilson loop for which the area law is assumed. The relativistic quark dynamics reduces for heavy q q bound states to three-dimensional Schrodinger equation with variable masses. A mechanism is discovered which generates dynamic (transverse) quark masses. Resulting Regge trajectories are asymptotically linear.