A stator for use in a positive displacement motor. The stator comprises a rubber compound including fiber reinforcement. The fiber reinforcement includes a plurality of elongated fibers. The elongated fibers in the fiber reinforcement create a grain direction generally with the grain in the longitudinal direction of the stator tube and across the grain in the transverse direction. The rubber compound has a 25% tensile Modulus that is at least 10% lower across the grain than with the grain. The fiber reinforcement includes a fiber loading of greater than about 2.5 phr of elongate fibers, the elongate fibers have a Modulus of greater than about 60 GPa, and the rubber compound has a 25% tensile Modulus of greater than about 400 psi against the grain and a 50% tensile Modulus of greater than about 700 psi against the grain. In some embodiments, the rubber reinforcement also comprises a blend of fibrillated fibers and short cut fibers.