Jason bowls right handed, but he uses his left hand as a guide. In fact, when you slow down his release via a high-speed video camera, you actually see him releasing the ball with one hand. His left hand comes off the ball before his right hand, meaning he's actually using an extended two handed approach. His left hand doesn’t come off the ball though till the very end of the release.
Jason holds the ball in both hands all the way through his push away and back swing. Having the left hand still attached to the ball means that the weight of the ball is split in both hands. So now he has less pressure on his wrist to create maximum amount of revolutions (an average of 600 RPM).
The back swing can’t be as high as a one of a handed bowler, because both his hands are still on the ball, so to generate ball speed he does two main things. He uses his hips and legs to produce ball speed, together with what has become a famous little ‘skip’ from his 3rd to his 4th into his sliding 5th step. These two main points are the main reason he can generate such high ball speed with such a small back swing. Due to smooth technique he has more ball speed and more power than almost every other bowler in the world, but he uses less effort. That’s an advantage for two handed bowling!
