  A rotation rate and X-ray luminosity analysis is presented for rapidly
rotating single and binary M-dwarf systems. X-ray luminosities for the majority
of both single & binary M-dwarf systems with periods below $\simeq 5-6$ days
(equatorial velocities, V$_{eq}>$ 6 km~s$^{-1}$) are consistent with the
current rotation-activity paradigm, and appear to saturate at about $10^{-3}$
of the stellar bolometric luminosity. The single M-dwarf data show tentative
evidence for the super-saturation phenomenon observed in some ultra-fast
rotating ($>$ 100 km~s$^{-1}$) G & K-dwarfs in the IC 2391, IC 2602 and Alpha
Persei clusters. The IC 2391 M star VXR60b is the least X-ray active and most
rapidly rotating of the short period (P$_{rot}<$ 2 days) stars considered
herein, with a period of 0.212 days and an X-ray activity level about 1.5 sigma
below the mean X-ray emission level for most of the single M-dwarf sample. For
this star, and possibly one other, we cautiously believe that we have
identified the first evidence of super-saturation in M-dwarfs. If we are wrong,
we demonstrate that only M-dwarfs rotating close to their break up velocities
are likely to exhibit the super-saturation effect at X-ray wavelengths.

Astrophysics