Sit on an anti burst swiss ball with the cable pulley height set at the level of your rib cage. Initiate the movement with your oblique muscles by concentrating on rotating your mid section and not pulling with your arms. Cable Rotations should always be executed with a controlled pace with the focus being on the core muscles and not the arms.
Dr. Eric Serrano MD uses a steady pace to support excellent form and range of motion. Keep a 10-20 degree elbow bend to prevent stressing the elbows. The number of reps listed withing a personalized training program should be done for each side.
Start with what you assume will be your weaker side. Take twenty seconds rest between sides. The movement should be challenging, but cannot be used with a high weight load due to the poor starting leverage. The objective is keep the focus on the core muscles.