Metallic glass resonators can possess larger quality factors (i.e., slower rates of energy dissipation) than typical polycrystalline metals, since metallic glasses are spatially homogeneous without dislocations and other topological defects. Using numerical simulations, we studied the energy dissipation mechanisms and measured the quality factor Q in model metallic glass cantilevers (panel (a)). We bend the cantilever to a given strain ε, release it, and measure Q from the Fourier transform of the cantilever displacement as a function of time. We also show that cyclic shear training can enhance Q. As shown in panel (b), Q for the trained system begins decreasing at a much larger strain than that of the untrained system. This work will contribute to making more sensitive resonators for applications in the electronics and communications industries.