if you watch your line, you can tell when they are about to jump. it's difficult to explain but when i see this, i go from a side to side, sweeping, controlling motion (according to the direction the fish is swimming) to raising my rod tip up, often times raising my whole rod above my head with one hand, similar to how fly-fishermen fight fish. This helps me keep the line tight while the fish is jumping. if you really want to keep them from jumping, when you see your line coming up, try and time it, so that you sweep your rod hard to the side, pulling the fish towards you in the same instant she jumps.