Stand holding a barbell on the back of your shoulders, grasping the barbell at each side.
Keeping your knees slightly flexed and your back and neck neutral, inhale as you flex your hips to lower your torso until it is close to, or fully, horizontal.
Exhale as you raise your torso back up to the starting position by extending your hips.
Repeat until you meet the desired number of repetitions.
Comments and tips
When performing the barbell good morning, you should only feel a mild stretch in your hamstrings. Do not flex your hips beyond this point.
Your range of motion will depend on the flexibility of your hamstrings. The less flexible your hamstrings are, the more you will need to flex your knees to lower your torso to your desired level.
Keep your back and neck neutral throughout the exercise.
Your erector spinae will be exercised isometrically, which means that it will contract but it will be held at a fixed length. Your erector spinae contract to stabilize your back.
In order to allow your lower back to adapt to the barbell good morning exercise, start with a light weight and add more weight in a gradual manner.
In hip-hinge exercises such as the barbell good morning, different muscles will be emphasized depending on how much your knees are flexed. If your knees are extended or only slightly flexed, as in the case of the barbell good morning, then your hamstrings will be emphasized over your gluteus maximus. On the other hand, if your knees are flexed, as in the case of the bent-knee barbell good morning, then your gluteus maximus will be emphasized over your hamstrings.