Forward bending of the back is known as flexion. Backward bending is known as extension. Back extensor muscles make this backward motion possible. In anatomical terms, they are known as the erector spinae or spinal erectors. They start at the base of the skull and run all the way down to the tailbone. Use the weight of your body and free weights to strengthen these muscles.
Straight-leg deadlifts work the spinal erectors, glutes and hamstrings all at the same time. While standing with your feet shoulder-width apart, hold dumbbells in front of your thighs with your palms facing you. Slowly bend forward at the hips as you lower the weights toward the floor. Stop when you feel a strong stretch in your hamstrings, rise back up by contracting your back muscles and repeat. For a variation, use one dumbbell at a time or grasp a barbell with a shoulder-width grip.
Hyperextensions require a 45-degree hyperextension bench, which is also known as a Roman chair. Stand on the foot rest, press your hips against the upper padded support and place the back of your lower legs against the lower padded support. Once into this position, either cross your arms over your chest or interlace your fingers behind your head. Slowly bend forward and down as far as possible, rise back up by contracting your back muscles and repeat. To increase the resistance, hold a barbell across your shoulders or hold dumbbells in front of your body.
Good mornings work your extensors from an upright standing position with your feet shoulder-width apart. While holding a barbell across your shoulders, keep your back and legs straight as you bend forward at the hips. The goal is to get your torso nearly parallel to the floor. Steadily rise back up and repeat. Use the bar by itself when you first start doing these and add weights gradually.
A shoulder bridge is performed from a face-up position on the floor with a stability ball. It also targets the glutes and hamstrings. After moving your arms out to your sides, prop your heels up on the ball, press down and lift your hips in the air. Once your have a straight line from your heels to shoulders, hold for a full second, lower yourself down and repeat. For a variation, raise one leg in the air when you lift your hips up. If you do not have access to a stability ball, use a chair, weight bench or sofa.
The locust pose is a yoga exercise that works the back extensors, butt, hamstrings and arms. While lying on your belly, rest your arms at your sides with your palms facing up. Steadily lift your torso and legs at the same time as high as possible. When doing this, keep your lower stomach and hips on the floor, arch your back and lift your arms so they are about level to the floor. Hold for 20 to 30 seconds. For a variation, perform these in motion. Hold each high point for a full second.