Lumbar lordosis is the natural inward curve of your lower back. Every healthy spine has this curve, which spans the five vertebrae (L1 through L5) between your ribcage and pelvis. It helps you stand upright, absorb shock when you walk, and distribute your body weight evenly. The average curve measures around 30 to 45 degrees, though this varies from person to person. Problems arise when the curve becomes too deep (hyperlordosis) or too flat (hypolordosis), both of which can cause pain and change how you move.
Why Your Lower Back Curves Inward
Your spine isn’t a straight column. Viewed from the side, it forms an S-shape: your upper back rounds slightly backward (kyphosis), while your lower back curves forward toward your belly (lordosis). This arrangement keeps your center of gravity balanced directly over your pelvis and legs, which is critical for walking on two feet.
The lumbar curve also protects your spine from compressive forces. When you walk, run, or jump, the curve acts like a spring, distributing impact across the vertebrae and the cushioning discs between them rather than concentrating it in one spot. Without this curve, standing upright for any length of time would place far more stress on the spine’s joints and ligaments.
What a Normal Curve Looks Like
Doctors measure lumbar lordosis using a method called the Cobb angle, which is calculated from an X-ray or specialized imaging. The angle is drawn between the top of the first lumbar vertebra (L1) and the bottom of the last one (L5). A large study using EOS imaging found the average lordosis angle to be about 32 degrees, with a standard deviation of roughly 6 degrees. Other studies measuring from T12 to S1 (which captures a slightly longer segment) report averages closer to 43 to 64 degrees, depending on the population and technique.
Lordosis develops gradually in childhood. Research tracking spinal curves in young people found that the lordotic angle increases from about 22 degrees at age five to 32 degrees by age 20. The curve can continue to shift modestly throughout adulthood and tends to change again in older age as discs lose height and muscles weaken. Notably, studies have found no significant difference in lordosis angles between men and women, though the peak of the curve may sit in a slightly different position in women, which is thought to help counterbalance the weight of pregnancy.
The Pelvis Controls the Curve
Your pelvis and lumbar spine are mechanically linked. When your pelvis tips forward (anterior pelvic tilt), it pulls the base of your spine forward and deepens the lordotic curve. When it tips backward (posterior pelvic tilt), the curve flattens. Research measuring this relationship directly found that adopting a maximum forward pelvic tilt increased lumbar lordosis by an average of 10.8 degrees, while a maximum backward tilt decreased it by about 9 degrees.
This connection explains why habits that affect pelvic position, like prolonged sitting, wearing high heels, or carrying excess abdominal weight, can gradually change your lumbar curve. It also means that exercises targeting pelvic position are one of the most direct ways to influence lordosis.
When the Curve Becomes Too Deep
Hyperlordosis, sometimes called swayback, is an exaggerated inward curve that pushes the hips forward and the buttocks backward. Common visible signs include your stomach appearing to jut forward, extra space beneath your lower back when lying flat on a hard surface, and your head and neck tilting further forward than usual. In more severe cases, the curve can cause low back pain, stiffness, and restricted movement.
Several things can push the curve too far:
- Obesity: Extra abdominal weight pulls the spine forward, forcing the lower back to arch more to compensate.
- Pregnancy: The growing uterus shifts the center of mass forward, and the spine responds with increased lordosis and a forward pelvic tilt. Maternal BMI is significantly associated with greater spinal curvature changes during late pregnancy.
- Weak core muscles: When the deep abdominal and back muscles can’t stabilize the spine, the lower back defaults to a deeper curve.
- Spondylolisthesis: A condition where one vertebra slips forward over the one below it, altering spinal alignment.
- Prolonged standing: People who stand for long periods with greater lordosis are more likely to develop low back pain. One study found that those who developed pain during prolonged standing had lordosis angles averaging 4.4 degrees greater than those who stayed pain-free.
When the Curve Is Too Flat
The opposite problem, called hypolordosis or flatback syndrome, occurs when the lower back loses its natural inward curve. This forces the trunk to tilt forward, making it difficult or impossible to stand fully upright without bending the hips and knees. People with flatback syndrome often experience chronic back pain and thigh pain from the constant muscle effort required to compensate. It can develop after spinal surgery, degenerative disc disease, or compression fractures that collapse the front of the vertebrae.
How Too Much Curve Affects the Spine
Even a modest increase in lordosis changes how forces are distributed across spinal structures. Cadaver studies show that a lordotic posture concentrates compressive loading on the posterior (back) elements of the vertebrae, including the facet joints and the outer layers of the intervertebral discs. An increase of just 2 degrees in lordosis can produce large stress peaks in the back portion of the disc, compared to a more even distribution in a neutral position.
These stress concentrations matter because the facet joints, joint capsules, and outer disc layers all contain pain-sensing nerve endings. High, focused pressure on these structures can trigger pain even without any visible tissue damage. If the loading exceeds what the tissue can tolerate over time, it can also lead to mechanical wear, contributing to disc degeneration and facet joint arthritis. The correlation between lordosis angle and pain intensity during prolonged standing has been measured at 0.46, meaning deeper curves are moderately but consistently associated with more pain.
Exercises and Management
For most people with mild hyperlordosis and associated back pain, the first line of management is exercise and over-the-counter anti-inflammatory medication. The goal of exercise is twofold: strengthen the deep core muscles that stabilize the spine, and improve pelvic control so you can reduce the excessive curve.
Core strengthening programs that have been studied for low back pain focus on retraining the deep trunk muscles rather than the superficial ones you’d target with standard crunches. Specific approaches include segmental stabilization exercises, which train the deep abdominal muscle (transversus abdominis) and the small muscles running along the spine (lumbar multifidus). A typical starting exercise involves drawing in the lower abdomen while exhaling, holding for 10 seconds with normal breathing, and gradually progressing to more dynamic movements like the cat-camel stretch on hands and knees.
Programs typically progress through positions: lying on your back, lying face down, sitting, hands and knees, and finally standing. Alternating between stable and unstable surfaces (like a firm floor versus a foam pad) challenges balance and forces deeper muscle engagement. These exercises differ from traditional gym work because the focus is on control and endurance of small, deep muscles rather than raw strength of larger muscle groups. Pelvic tilt exercises, where you consciously flatten your lower back against the floor while lying down, directly practice the posterior tilt that reduces lordosis by about 9 degrees.
Severe or rigid curves that don’t respond to conservative treatment may require bracing in children or, rarely, surgical correction. But the vast majority of people with excessive lordosis improve with consistent core training and attention to posture, particularly during prolonged standing.