We study a non trivial influence of the kinetic energy on equilibrium points of Hamiltonian systems following the second part of Garcia & Tal article The influence of the kinetic energy in equilibrium of Hamiltonian systems [5]. In this article the authors show, for an explicit example of C ω (R 4) Hamiltonians defined by H i = T i + π for i ∈ {1, 2}, that the attraction basins of H 1 and H 2 have distinct dimensions as submanifolds of R 4. We'll discuss how this result is related to the study of the stability according to Liapunov of equilibrium points of Hamiltonian systems and especially how it is related to the inversion of the celebrated Lagrange-Dirichlet theorem. Finally we'll prove a new theorem which extends the result above for a whole family of potential energies π α,β,k. We show that, if the parameters α, β, k satisfy a simple arithmetical criteria then the attraction basins of H i = T i + π α,β,k have different dimensions for i ∈ {1, 2}.