We use the spectral shapes of the EUV line profiles to study the plasma dynamics, acceleration and heating, in polar plumes (PP). We find that the observed profiles are reproduced fairly well when considering low plume wind speeds and velocity turbulence $(\alpha_S)$ at low altitudes followed by a rapid acceleration and heating of the plasma to reach the properties of inter-plumes (IP) by $\approx3-4~R_\odot$. We also find that plumes very close to the pole give narrow profiles at all heights that are not observed above $\approx2.5~R_\odot$. This suggests a tendency for plume footpoints to lie more than 10° away from the pole. High resolution magnetograms of SOLIS and EUV images support this hypothesis.