I think the calves get strong enough from sprinting alone, especially if you run in spikes a couple times a week. Power doesn't really come from the calve muscle anyhow, it's more from the hip extensors, knee flexors and knee extensors. You also don't want to develop big calves because it would be a huge mechanical disadvantage.
The hip extensors are the glute and hamstring complexes. You can work them with RDLs, straight leg dead lifts, deep squats, dead lifts, pulls from the floor (including OL and all variants), glute-ham extensions, and reverse hyperextensions among other exercises.
