In this talk, we discuss confined subgroups in groups with contracting elements. This class of subgroups generalizes normal subgroups and has recently received many interests in semi-simple Lie groups. We shall study the growth of confined subgroups through Hopf decomposition of conformal measures on boundaries. Our results apply to confined subgroups in the fundamental group of negatively pinched Riemannian manifolds and mapping class groups. This represents a joint work with Inheyok Choi, Ilya Gekhtman, and Tianyi Zheng.