  Near the critical temperature of a superconducting transition, the energy of
the threshold perturbation $\delta F_{thr}$ that transfers a superconducting
bridge to a resistive state at a current below the critical current $I_c$ has
been determined. It has been shown that $\delta F_{thr}$ increases with a
decrease in the length of a bridge for short bridges with lengths $L<\xi$
(where $\xi$ is the coherence length) and is saturated for long bridges with
$L\gg \xi$. At certain geometrical parameters of banks and bridge, the function
$\delta F_{thr}(L)$ at the current $I\to 0$ has a minimum at $L\sim 2-3 \xi$.
These results indicate that the effect of fluctuations on Josephson junctions
made in the form of short superconducting bridges is reduced and that the
effect of fluctuations on bridges with lengths $\sim 2-3 \xi$ is enhanced.
