Star formation takes place inside dense and cold clouds composed mainly of molecular gas and known as giant molecular clouds. Its study in galaxies is currently of great interest since we still do not understand the detailed physical mechanisms that drive the formation of stars. With the aim of improving our understanding of the star formation process in galaxies, in this talk I will present observations of a sample of galaxies characterized by their high infrared luminosities (LIRGs). We began by studying the nearby Seyfert 2 barred galaxy NGC1068 and then focused on a sample of 16 local LIRGs that feature different morphologies. Throughout this work we have studied each galaxy using interferometric observations at high angular resolution. In addition, we have complemented these observations with images of the Pa-line emission in the near infrared. Our work focuses mainly on the study of the star formation laws, covering a wide range of molecular gas densities. To carry out this study, we have performed the necessary observations and analysis to obtain the physical quantities with which we determine the gas properties and the rate of recent star formation. We analyse the SF relations with gas tracers with different critical densities at several scales and after that we study an alternative prescription of the star formation relations that correlates the star formation efficiency with the boundedness of the gas. This prescription shows the importance of the dynamical environment of the gas when it comes to forming stars. The results obtained in this work suggest that galactic dynamics plays an important role in the efficiency of converting the gas into stars.