The crack propagation problem for linear elastic fracture mechanics has been studied by several authors exploiting its analogy with standard dissipative systems theory (see e.g. ( Nemat-Nasser et al., 1980; Nguyen, 2000; Maugin, 1992; Bourdin et al., 2008; Salvadori, 2008). This approach is here further advanced, by noting that Stress Intensity Factors (SIFs) asymptotic expansion ( Amestoy et al., 1986; Amestoy and Leblond, 1992) enjoys a Colonnetti’s decomposition ( Colonnetti, 1918; Colonnetti, 1950) interpretation. As a consequence, minimum theorems are derived in terms of crack tip “quasi static velocity”. They are reminiscent of Ceradini’s theorem ( Ceradini, 1965; Ceradini, 1966) in plasticity.