The lumbar lordosis is the anatomically normal shape of the lumbar shape. There is a huge difference between age, sex, total lumbar lordosis and the individual mobility each patient shows (Dreischarf et al., 2014).
In case of being excessive it can cause back, hip and leg pain and may be causing other imbalances elsewhere in the body. It can be hereditary but often it is related to poor posture when standing. Additionally tight hip flexors (or general flexion deformity of the hip) and poor core stability can contribute to this. Moreover weak abdominal muscles can be resulting into an plus lordosis, usually compensated by a thoracic kyphosis (Ombregt, 2013).
Treatment involves improving your postural awareness, stretching and strengthening the muscles of your core
Dreischarf M. et al., 2014, Age-Related Loss of Lumbar Spinal Lordosis and Mobility- A Study of 323 Asymptomatic Volunteers, PLoS One, 9(12), e116186
Ombregt L., 2013, A System of Orthopedic Medicine, 3rd Edition, Churchill Livingstone Elsevier, London, UK, p: 501