A polynomially bounded recursive realizability, in which
the recursive functions used in Kleene's realizability are
restricted to polynomially bounded functions, is introduced. It is used
to show that provably total functions of Ruitenburg's Basic
Arithmetic are polynomially bounded (primitive) recursive functions. This sharpens our earlier result where those functions were proved to be primitive recursive. Also a polynomially bounded schema of Church's Thesis is shown to be polynomially bounded realizable. So
the schema is consistent with Basic Arithmetic, whereas it is
inconsistent with Heyting Arithmetic.