Back isolation exercises are vital for developing a strong lower back. However, the muscles of the lower back -- erector spinae and quadratus lumborum -- are often overlooked in a training plan. For athletes, increased spinal erector and quadratus lumborum strength can help prevent injuries and develop muscle, and for the general public, a strong lower back prevents back pain or can help manage it. An effective exercise to target these muscles is the lower back extension.
Back Extensions for Beginners
If you're recovering from a lower back injury or training your lower back directly for the first time, start with basic back extensions. Your first step is prone extension. Lie on your front, prop yourself up on your elbows and arch your lower back slightly. In 2013 physical therapist Ron Miller of Spine-Health.com recommended starting with a five-second hold and working your way up to 10 sets of 30-second holds. Once you're comfortable with this, progress the move by lying on your stomach with your arms at your sides and lifting your head, torso and legs off the floor.
Having a Ball
Your next step is to progress to stability ball back extensions. These are performed in exactly the same way as the more challenging version of the floor back extensions, but you lie with your stomach and thighs on a stability ball. The added element of balance means your lower back has to work harder not only to perform the extension movement, but to stabilize you as well.
Seeing the Specialist
Some gyms have specialist back extension machines with weights. One type has an upright seat with a pad that your rest your back against and lean backward on. Another features a platform with a small pad between 45 and 90 degrees to the ground that your rest your legs on and a plate to secure your feet underneath. The advantage of the first machine is that you can easily change the weight, but the second machine may provide a more natural range of movement.
Getting Hard Core
Once other forms of extension become too easy, start looking at more advanced lower back moves. Using a body-weight extension machine, you can perform many different types of weighted back extensions. These can be done by holding a weight plate to your chest, draping weighted chains over your shoulders or securing a resistance band under the apparatus and over your upper back to add tension. Alternatively, perform the single-legged back extension for a real challenge. For this, simply position yourself on the body-weight back extension machine, then take one leg from underneath the support pad, let it hang to the side and perform back extensions.