Our back muscles are important structural components of our core. While these muscles are responsible for trunk mobility, they also play an important role in stabilizing the spine, the shoulder blades, and the hip bones in order to maintain posture and body alignment during activities of daily living.
However, this is a region often neglected by many of us. Our sedentary lifestyle and the fact that we tend to spend most of our day seated, contribute to muscle atrophy and weakness, which leads to poor posture and back pain. Did you know that it is estimated that 80% of adults will experience low-back pain at some point in their lives?
Another very common issue is that many people are inclined to focus on the front part of their bodies during training, emphasizing the chest, abdominals, and quads muscles. The result is weak and underdeveloped back, glutes, and hamstring muscles that are easily overpowered by their antagonists[1]. These imbalances put the lumbar spine under great stress, which can misplace vertebrae and compress disks.
Low-back pain may have several causes such as ligament strains, muscle sprains, disk injuries, and arthritis, among others. If you suffer from chronic back pain, you might want to consult your heath care provider prior to starting an exercise program. He/she can identify the cause and provide guidelines for your program. But if you are part of the 20% of the lucky ones who haven’t experienced back pain yet, you should consider strengthening exercises as a preventive measure. Learning how to properly lift heavy loads and stretching tight muscles are also effective ways to prevent back injuries.
Lower Back Anatomy and Kinesiology[2]
The low-back constitutes the lumbar region of the vertebral column, extending from the 12th thoracic vertebra (T12) to the sacrum (S1). The lumbar vertebrae are large, and their disks are thick in order to receive body weight and redistribute it to the lower limbs. This region presents a great range of motion for flexion (forward bending), extension (back bending), and lateral bending (side bending), but rotational movements are limited.
The stability and alignment of the vertebrae and intervertebral disks is maintained by deep spinal muscles. The erector spinae muscle group, as its name implies, helps the deeper muscles keep the spine straight, but also contributes to trunk and pelvic movements. The quadratus lumborum muscle stabilizes or mobilizes the pelvis and lumbar spine, depending on the task at hand. For example, this muscle is one of the ones responsible for trunk side bending. However, when you walk, it works by pulling the pelvis up so you can take a step forward. The iliopsoas muscle, a potent hip flexor, attaches the lumbar spine to the hip bones. This muscle is responsible for the maintenance of the natural curvature of the lumbar spine. However, when this muscle is stronger than its antagonists[3], it rotates the pelvis forward, exacerbating the lumbar curvature, which places the region under great stress.
Strengthening the glutes and hamstring muscles can help prevent this situation, because even though they are not part of the low-back region, these muscles are hip extensors, counteracting the action of the iliopsoas muscle.
Training the Lower Back
When training the low-back muscles, your primary goal should be to improve spinal stabilization and core strength. Isometric (static) exercises may be more appropriate for beginners. If you are just starting to exercise, you can include the following exercises into your routine, once or twice a week.
1. Spinal balance
Kneel on all fours, positioning the hands under the shoulders, and the knees under the hips. Engage your abdominals, and extend your right arm and your left leg, keeping the back straight and the spine neutral (neither rounded nor arched). Hold this position for five deep breaths and return to the initial position. Repeat with the opposite side.
2. Bridge
Lie down on the floor with your belly up, and bend both knees, placing the feet on the ground. Place your arms by your side; you should be able to touch your heels with the tip of your fingers. If not, bring your feet closer to the glutes. Slowly, lift the pelvis off the floor, contracting your glutes and abs. Hold this position for five deep breaths, then roll down one vertebra at a time until your pelvis is back on the floor. Repeat two more times.
3. Sphinx
Lie down facing the floor. Bend your elbows and place your arms close to your torso. Slowly lift your upper-body, sliding your hands forward until your elbows are directly under your shoulders. Hold this back bend for five deep breaths or until it is comfortable for you. Return to the starting position and repeat. After you are done with this exercise, you might want to engage in a counter-pose to stretch the back muscle. From a kneeling position, sit on your heels and bend forward, stretching your arms in front of you. This is known as “child’s pose”, and it is a common relaxation yoga pose.
References
Calais-Germain, B. Anatomy of Movement. Seattle: Eastland Press. 2007.
Floyd, R. T. Manual of Structural Kinesiology. New York: McGraw-Hill. 2009.
Golding, L. and Golding, S. Fitness Professionals’ Guide to Musculoskeletal Anatomy and Human Movement. Monterey: Healthy Learning. 2003.
Karminoff, L. Yoga Anatomy. Champaign,Il: Human Kinetics. 2007.
Vella, M. Anatomy for Strength and Fitness Training. New York: McGraw-Hill. 2007.