Keep your elbows positioned as high as possible throughout the set, and dont move them as you extend your arms.
Pause and squeeze the triceps at the top of the movement.
Keep the rep timing slow and control the weight.
Instructions
Set up for the two arm cable tricep kickback by attaching either a long rope, or two single grip handles to a low pulley cable and selecting the weight you want to use on the stack.
Grasp the rope with a neutral grip (thumbs facing the pulled machine) and step back from the machine.
Bending your knees slightly and keeping your elbows tucked in at your sides, bend down until your torso is around parallel to the floor.
If the cable is not tensioned, take a step back. This is the starting position for the exercise.
Keeping your body fixed, slowly extend your arms as far as possible.
Squeeze the triceps, and then slowly lower back to the starting position.