Theoretically could you?

no. because no matter what, you would have to go through the same amount of acceleration to stop yourself. so you could do that one of two ways: either hit the ground, and allow it to stop you, or jump off something with enough force to counter gravity. if you took the first alternative, you would go splat. if you took the second alternative, you would have to generated the same force in a millisecond that gravity has been exerting on you for the past however many seconds you've been falling. so unless you are falling from less than a reasonable distance (around 10 feet, perhaps) it would be impossible to generate that much force using your legs alone. thus, its impossible, even in theory. oh, even if you hit terminal velocity, you'd have to generate a pretty considerable force.