The adherence energy measured during the separation of adhesive/substrate assemblies is a complex function of the adhesion energy and also of the dissipative properties of both adhesive and substrate. Dissipative phenomena occurring during an assembly separation are reflected in the dependence of the measured energy on separation rate. Up to now, different relationships have been used to describe the dependence of the adherence energy G on separation speed V. However, these models assume that only the separation speed affects the dissipation function; the adhesion energy W is supposed to remain constant. This paper proposes that the "real" adhesion energy is also rate dependent, Indeed, the number of interfacial interaction points under stress is able to increase with speed. This effect could be a consequence of the influence of separation rate on the adhesive elastic modulus,