The lower back extension is one of those exercises which is about precision and focus.
Perform it as such and it will deliver the right results.
The key here is not to rush the exercise itself and to use the equipment sensibly (as I am doing in this video). The lower back extension is a simple exercise and one which adds strength and good posture as a result of undertaking it.
Add this exercise regularly to your gym routine and your back will thank you for it!