  A global event shape analysis of the multihadronic final states observed in
neutral current deep inelastic scattering events with a large rapidity gap with
respect to the proton direction is presented. The analysis is performed in the
range $5 \leq Q^2 \leq 185\gev^2$ and $160 \leq W \leq 250\gev$, where $Q^2$ is
the virtuality of the photon and $W$ is the virtual-photon proton centre of
mass energy. Particular emphasis is placed on the dependence of the shape
variables, measured in the $\gamma^*-$pomeron rest frame, on the mass of the
hadronic final state, $M_X$. With increasing $M_X$ the multihadronic final
state becomes more collimated and planar. The experimental results are compared
with several models which attempt to describe diffractive events. The
broadening effects exhibited by the data require in these models a significant
gluon component of the pomeron.
