And why would you want to jump? Why would you want a burst of acceleration and movement to move you from where you are now, through the air, to land back here again or to move forward?
Would jump because it feels good? Would you jump because you crave that moment when you defy gravity? Would you jump because a large object is on a crash course with you?
Once your muscles are coiled and ready, it will be easier to jump than to stop yourself.