How important are the calves for jumping?
Not very important. Try this: Stand on a stair step and let your ankles hang down. Without bending your knees try to hop up onto the next step. Did you make it? Probably not. That’s because the calves don’t contribute much to the jump. Your butt and thighs are what give you the power. The calves simply help transferring that power into the ground. Having said that, many people do have a problem with what appears to be weak calves because when they move they struggle to stay in optimal power position – They move back on their heels and have a hard time staying up on the balls of their feet. Their problem isn’t really weak calves it’s lack of coordination on the feet. Exercises designed to improve movement efficiency will improve this.
