Calf workout using a trampoline

What do you do to workout your calf muscles?

As part of my total workout with weights, I have been doing sets of calf raises with a cross bow machine (similar to a bow flex machine), plus I use an older basically antique Life Cycle 5000 stepping machine which is a great cardio and leg workout.

Recently immediately after doing the calf raises and stepper, I got on my wife's new mini trampoline and started doing slight bouncing calf raises on it. I was keeping the balls of my feet in contact with the trampoline and only lifting my heels with a slight bouncing calf raising motion. I thought that would be really easy, but immediately after working my calves, I was amazed how well calf raises on a mini trampoline thoroughly wear down your calf muscles to exhaustion. I had read that maintaining your balance on a trampoline activates something like 30% more of your muscles doing the same motion not on a trampoline.