  We derive the coherent state representation of the integrable spin chain
Hamiltonian with symmetry group SL(2,R). By passing to the continuum limit, we
find a spin chain sigma model describing a string moving on the hyperboloid
SL(2,R)/U(1). The same sigma model is found by considering strings rotating
with large angular momentum in AdS_5xS^5. The spinning strings are identified
with semiclassical coherent states built out of SL(2,R) spin chain states.
