In this work, we investigate the performance of Mobile Ad Hoc networks (MANETs) in terms of the throughput achieved in transferring packets from source to destination. First, we study the relationship between mobility and routing and define metrics that enable us to derive an analytical expression for the throughput. Secondly, we validate this expression, via simulations, as a function of several mobility patterns, as well as routing protocols, for various nodes speeds. Eventually, we propose the use of additional fixed relays so as to enhance the throughput performance in case of ill-behaved mobility schemes