That looks like about the growth I would expect from the second year.
Try cultivating around the plant but shallow enough that you don't disturb the roots, add some topsoil with a high nitrogen and iron content. Fertilize them every couple of weeks with a liquid fertilizer like Miracle Gro. Hops like a lot of water. If they start to flower switch to a super-bloom type fertilizer for the last month. Pick the hops off and let the leaves remain until they die in the late fall. Cut back the bines to the ground and cover the roots with mulch until next spring.