  We present spectroscopic rotation velocities (v sin i) for 56 M dwarf stars
using high resolution HET HRS red spectroscopy. In addition we have also
determined photometric effective temperatures, masses and metallicities
([Fe/H]) for some stars observed here and in the literature where we could
acquire accurate parallax measurements and relevant photometry. We have
increased the number of known v sin is for mid M stars by around 80% and can
confirm a weakly increasing rotation velocity with decreasing effective
temperature. Our sample of v sin is peak at low velocities (~3 km/s). We find a
change in the rotational velocity distribution between early M and late M
stars, which is likely due to the changing field topology between partially and
fully convective stars. There is also a possible further change in the
rotational distribution towards the late M dwarfs where dust begins to play a
role in the stellar atmospheres. We also link v sin i to age and show how it
can be used to provide mid-M star age limits. When all literature velocities
for M dwarfs are added to our sample there are 198 with v sin i less than or
equal to 10 km/s and 124 in the mid-to-late M star regime (M3.0-M9.5) where
measuring precision optical radial-velocities is difficult. In addition we also
search the spectra for any significant Halpha emission or absorption. 43% were
found to exhibit such emission and could represent young, active objects with
high levels of radial-velocity noise. The tables presented here will aid any
future M star planet search target selection to extract stars that will exhibit
low radial-velocity jitter.
