We describe the asymptotic behaviour of a cylindrical elastic body, reinforced along identical ε-periodically distributed fibers of size rε, with 0 < rε < ε, filled in with some different elastic material, when this small parameter ε goes to 0. The case of small deformations and small strains is considered. We exhibit a critical size of the fibers and a critical link between the radius of the fibers and the size of the Lamé coefficients of the reinforcing elastic material. Epi-convergence arguments are used in order to prove this asymptotic behaviour. The proof is essentially based on the construction of appropriate test-functions.