  Dynamic buckling of an elastic column under compression at constant speed is
investigated assuming the first-mode buckling. Two cases are considered: (i) an
imperfect column (Hoff's statement), and (ii) a perfect column having an
initial lateral deflection. The range of parameters, where the maximum load
supported by a column exceeds Euler static force is determined. In this range,
the maximum load is represented as a function of the compression rate,
slenderness ratio, and imperfection/initial deflection. Considering the results
we answer the following question: "How slowly the column should be compressed
in order to measure static load-bearing capacity?" This question is important
for the proper setup of laboratory experiments and computer simulations of
buckling.
  Additionally, it is shown that the behavior of a perfect column having an
initial deflection differ significantlys form the behavior of an imperfect
column. In particular, the dependence of the maximum force on the compression
rate is non-monotonic. The analytical results are supported by numerical
simulations and available experimental data.
