  We discuss the dynamics of quarks within a Vlasov approach. We use an
interquark ($qq$) potential consistent with the indications of Lattice QCD
calculations and containing a Coulomb term, a confining part and a spin
dependent term. Hadrons masses are shown to arise from the interplay of these
three terms plus the Fermi motion and the finite masses of the quarks.
  The approach gives a lower and an upper bound for hadrons. The theoretical
predictions are shown to be in fairly good agreement with the experimental
data.
