If available, you can use a cable machine for this exercise.
Alternatively, fix a resistance band to a solid object at the floor height behind you.
Sit in a chair with your feet flat on the floor and loop the resistance band around your midfoot.
When ready, keep the back of your thigh against the chair and straighten your knee against the resistance of the band.
In a controlled manner, allow your knee to bend back to the starting position.
