Lock the carriage so that the bar is just below the knees.
Assuming a broad stance, stand behind the bar in squatting position. Grasp bar with a wide alternating grip. The back is slightly arched throughout the whole exercise. The head forms an extension of the spine. Look 45° to the ground. Keep the back straight with full tension at all times.
When straightening up, always have the arms extended. The power comes from the legs and the lower back muscles. In end position, the shoulders are pulled back, but not raised.
The performance of this exercise is extremely complex and it should only be done under the supervision of a trainer or experienced training partner.