We present a study of the membrane and shear locking behavior in an isoparametric curved beam element. The objective is to gain insight into the locking phenomenon, specially membrane locking, of continuum based degenerated shell elements. This is possible since the isobeam element is the one-dimensional analogue of the continuum based shell element. In this context, reduced integration and mixed interpolation schemes are briefly examined. Such a study can be a valuable aid when developing new shell elements.