  Radial excitations of the quark-antiquark string sweeping the Wilson-loop
area are considered in the framework of the effective-action formalism.
Identifying these excitations with the daughter Regge trajectories, we find
corrections which they produce to the constituent quark mass. The energy of the
quark-antiquark pair turns out to be mostly saturated by the constituent quark
masses, rather than by the elongation of the quark-antiquark string.
Specifically, while the constituent quark mass turns out to increase as the
square root of the radial-excitation quantum number, the energy of the string
increases only as the fourth root of that number.
