Adjust tower unit. Fold back cross bar and stand on top step. Grip lateral bars and take your weight with your arms, bending your knees. Bend elbows in order to lower body slowly into fully extended position. Raise body back to starting position without using your feet as support. Do not straighten elbows fully. Hold this position briefly. Repeat until a full movement is no longer  possible.

Negative version:
Just do first part of exercise, i.e. lower body into extended position. This movement should take about ten seconds. Then climb back up to top step and repeat until a full movement is no longer possible. You can increase the load further  by using the belt.

Important: Make sure that elbows remain in line with body and not behind it.