What is the Superman seat-grab?

In freestyle motocross, when the rider is in the air, it is termed `Big Air’. Superman seat-grab is considered a regular trick in which, when the rider is in the air (18 m is the minimum suitable height for performing this trick), puts one hand on the handle bar and other grabs the seat of the bike, and extends the lower body up in the air. A few riders keep their legs closed, others curve and open them slightly in the air. It is not to be confused with the ‘Hart-attack’ technique, which is slightly different.