  We consider the problem of internal particle state transformation, which is a
bound state of several constituents, from the particle's rest frame to the
system in which this particle is relativistic. It is assumed that in the rest
frame of the composite particle, its internal state can be considered in the
nonrelativistic approximation. It is shown, that this internal state is
unchanged during the transition from one reference frame to another. Namely,
given the particle is spherically symmetric in the rest frame, it remains
spherically symmetric in any other reference frame, and does not undergo
Lorentz contraction along the direction of motion of moving reference frame
with respect to the rest frame. We discuss a possible application of these
results to the description of hadron-hadron scattering, considering hadrons as
a bound states of quarks.
