  Measurements of the physical properties of stars at the lower end of the main
sequence are scarce. In this context we report masses, radii and surface
gravities of ten very-low-mass stars in eclipsing binary systems, with orbital
periods of the order of several days. The objects probe the stellar mass-radius
relation in the fully convective regime, $M_\star \lesssim 0.35$ M$_\odot$,
down to the hydrogen burning mass-limit, $M_{\mathrm{HB}} \sim 0.07$ M$_\odot$.
The stars were detected by the WASP survey for transiting extra-solar planets,
as low-mass, eclipsing companions orbiting more massive, F- and G-type host
stars. We use eclipse observations of the host stars (TRAPPIST, Leonhard Euler,
SPECULOOS telescopes), and radial velocities of the host stars (CORALIE
spectrograph), to determine physical properties of the low-mass companions.
Companion surface gravities are derived from the eclipse and orbital parameters
of each system. Spectroscopic measurements of the host star effective
temperature and metallicity are used to infer the host star mass and age from
stellar evolution models. Masses and radii of the low-mass companions are then
derived from the eclipse and orbital parameters of each system. The objects are
compared to stellar evolution models for low-mass stars, to test for an effect
of the stellar metallicity and orbital period on the radius of low-mass stars
in close binary systems. Measurements are in good agreement with stellar
models; an inflation of the radii of low-mass stars with respect to model
predictions is limited to 1.6 $\pm$ 1.2% in the fully convective regime. The
sample of ten objects indicates a scaling of the radius of low-mass stars with
the host star metallicity. No correlation between stellar radii and orbital
periods of the binary systems is determined. A combined analysis with
comparable objects from the literature is consistent with this result.
