The human spine has a natural "S" curve that makes it incredibly resilient. The three curves in the spine all have to function properly for the spine to work. If even one curve becomes flat it will change the way that the rest of the spine moves and make it more vulnerable to injury. Perform stretching and strengthening exercises to prevent or fix a flat spine.
Curvature of the Spine
The three curves to the spine are the cervical at the neck, the thoracic where your ribcage is located and the lumbar at the lower back. The lumbar spine and cervical spine both curve in the same direction -- forwards. The thoracic spine is the only section of your spine that curves backward.
Read More: Flat Back & Posture
The curves of your spine allow it to bend to absorb forces from activities like landing, ing something heavy and even running. By bending, the spine decreases the shock it receives in the same way that your knees bend when you land from a jump.
Flat Spine Syndrome
If part of your spine starts to flatten out due to a change in posture, it affects the other parts of your spine by increasing the amount of force that the other parts of the spine experience. There are two ways that you can develop a flat back. The first comes from a change in posture. If your lower back is flat it's because your pelvis is rotated back and your shoulders are rounded forward slightly. If your thoracic spine is flat it's caused by standing tall with the shoulders pulled back.
The other cause comes from surgery. If you've had part of your spine fused or fixed with a metal rod it can lead to postural problems like a flat back because part of the spine was manually flattened. Surgery is much more permanent than a postural problem, making it much more difficult to fix.
To fix your postural flat back problem, you have to determine whether it's your lumbar spine or thoracic spine that is flat. You can check in a mirror or have a medical professional give you a postural assessment. There are different exercises for restoring the natural curve of the lumbar spine and thoracic spine.
Lumbar Spine Exercises
These exercises help restore the natural lordotic curve of the lumbar spine.
Use this exercise to practice strengthening your lower back muscles, such as the erector spinae and multifidus, which can help pull the lower back into lordosis.
How To: Stand tall with your feet shoulder-width apart, holding one dumbbell in each hand. Pull your shoulders back and stick your chest out. The dumbbells should be in front of you, resting against the front of your thighs. Lean forwards, keeping your shoulders pulled back, and stick your butt back, running the dumbbells down the front of your legs. Keep your knees as straight as possible. Continue to lean forwards and stick your butt back until you can't go down any farther.
Seated Hip Flexion
A 2013 study in the Journal of Physical Therapy Science listed this exercise as one that effectively strengthens your hip flexors. The hip flexor muscles can pull your pelvis forward to fix flat back syndrome. To make the exercise harder, use ankle weights.
How To: Sit in a chair or on a bench. Plant your feet on the ground with your knees bent at 90 degrees. Sitting tall, lift one leg up as high as you can, keeping your knee bent. Hold it for one second and then lower the leg back down and switch sides.
Read More: How to Improve Your Lower Back Curve
Thoracic Spine Exercises
These exercises help restore the kyphotic curve of the middle section of your back.
This breathing exercise teaches you how to round your thoracic spine.
How To: Get on the ground on your hands and knees. Breathe out and round your back as much as possible, letting your head hang down. Keep your back rounded as you breathe in. Exhale again and round your back even more. Repeat this process three more times, then relax.
Use this exercise to stretch your lats, a back muscle that pulls your shoulders back. Tightness in the lats contributes to a flat back.
How To: Stand with your feet closer than shoulder-width apart and grab a fixed object about waist-high. Squat down as low as possible and round your upper back. Breathe in and let your shoulders and the sides of your back lengthen. Breathe in and out five times, then stand up.