This thesis studies the following question: given a finitely generated group G which are the elements whose length is uniformly bounded for any word-length in G ?. This work introduces and studies the subgroup Gbound consisting of elements of uniformly bounded word-length with respect to any generating set of G. We show that this subgroup is characteristic, that it is finite when the group G is virtually abelian, that it is trivial when the group is non-elementary hyperbolic. We show that for every finite group A, there exists an infinite group G such that Gbound = A. It is shown that for nilpotent groups of class 2, Gbound is the largest finite subgroup of the lower central series. We also study a generalization of Gbound by making it depe...