  We investigated the magnetoelastic properties of the quasi-one-dimensional
spin-1/2 frustrated magnet LiCuVO$_4$. Longitudinal-magnetostriction
experiments were performed at 1.5 K in high magnetic fields of up to 60 T
applied along the $b$ axis, i.e., the spin-chain direction. The
magnetostriction data qualitatively resemble the magnetization results, and
saturate at $H_{\text{sat}} \approx 54$ T, with a relative change in sample
length of $\Delta L/L \approx 1.8\times10^{-4}$. Remarkably, both the
magnetostriction and the magnetization evolve gradually between $H_{\text{c3}}
\approx 48$ T and $H_{\text{sat}}$, indicating that the two quantities
consistently detect the spin-nematic phase just below the saturation. Numerical
analyses for a weakly coupled spin-chain model reveal that the observed
magnetostriction can overall be understood within an exchange-striction
mechanism. Small deviations found may indicate nontrivial changes in local
correlations associated with the field-induced phase transitions.
