The strong coupling constant plays a central role in the quest for precision at the LHC. Nowadays lattice QCD provides the most precise determinations of alpha_s. In this talk I will review the main ideas and limitations behind the different approaches to determine alpha_s in lattice QCD. Finally, I will explain a new proposal, based on using heavy quarks as a way to match QCD with the pure gauge theory. This strategy allows to relate non-perturbatively the running of the strong coupling in the pure gauge theory and in QCD. Together with a very precise determination of the non-perturbative running in pure gauge, this new strategy promises to achieve an unprecedented precision in the determination of the strong coupling.