Have you guys seen QWOP, the hardest flash game ever? This guy has:
My personal best: 2.3 meters and the most hyper-extended knee you will ever see. Want to try it for yourself? Hit this link. I’d embed it for you but I hardly even know you.
My prediction: The next time I see my friend Dave he will have mastered it. After only 3 sleepless nights. Have fun, Dave!