Instructions
Attach ankle straps to each ankle, with the metal hooks facing away from the foot. Sit on the edge of a bench or high box facing away from the cable machine. Attach one of the ankle straps to the cable attachment. Hold on to the bench, brace your core and extend your knee. Once the knee is fully extended, slowly return to the start position and repeat for the desired number of repetitions then repeat on the other side.
Tips
The taller you are the higher the bench or box will need to be. A way to do this is to place the bench on large bumper plates.