The Benefits - Barbell Goodmorning exercise is a good isolation exercise to lower back. If you want to work your lower back specifically, perform goodmorning exercises with using a light to moderate weight.

Execution – Bring the bar on the back of the shoulders. Lower your upper torso by bending your hips until it’s parallel to floor and at the same time bend your knees slightly. This will decrease the pressure in your lower back. At the bottom, keep your head up and lift your torso up by extending your hips.

Tips - Learn the technique properly first, before you start using heavier weights. However I don’t recommend to use extra heavy weights in bearbell goodmorning exercise. Few years ago when I aimed for strenght and raw power, I did barbell goddmornings with 300lb. X-)