In order to set up for this exercise, place a bench behind your back, perpendicular to your body. Hold on to the bench on its edge with your hands (looking away from the bench), keeping your arms fully extended. The width of your hands should be approximately one shoulder width apart, but feel free to deviate slightly from this if it is more comfortable for your shoulder joints. The legs should be straight and extended forward, with the heels on the ground. This is the setup for the easiest version of the exercise. In order to make it slightly more difficult, you can place your legs on top of another flat bench in front of you. To make it even more challenging, you can further add weight by placing plates across your lap to add more resistance.
To execute the movement, slowly lower your body by bending the elbows until your upper arm and forearm form an angle that is less than 90 degrees. Try to not flare your elbows outwards as you make this descent. Then, use your triceps to bring your torso back up until you are once again in the starting position. Repeat for the prescribed number of repetitions.