There are many “posture police” out there, and you may be one of them. Physical Therapists talk to patients about it all the time, urging them to “sit up straight,” “tighten your tummy muscles,” “keep your shoulders back and your head up.” It is intuitive to think that if someone has a large thoracic kyphosis (a hump on their upper back) and neck pain, we should fix their posture and the pain will improve.
It makes sense that poor posture leads to back pain…or does it? Should we spend time looking for postural abnormalities and asymmetries? Should we attempt to correct deviations from what is considered ideal? Recent studies may be able to provide some insights and answers to some of our most pressing questions regarding posture and pain.
Research looking for correlations between back pain and posture typically involves a couple of different study designs – most frequently cross sectional studies and prospective studies. The results aren’t completely cut and dry, but most do not support the theory that bad posture causes back pain.
Here are some of the findings:
- No association between leg length inequality and back pain. 
- No significant difference in lumbar lordosis or leg length inequality between three groups of 321 males with severe back pain, moderate pain, or no pain. 
- No association between measurements of neck curvature and neck pain. 
- No significant difference in lumbar lordosis, pelvic tilt, leg length discrepancy and the length of abdominal, hamstring and iliopsoas muscles in 600 people with and without back pain. 
- Teenagers with postural asymmetry, excessive thoracic kyphosis and/or lumbar lordosis were no more likely to develop back pain in adulthood than peers with “better” posture. 
- Pregnant women with greater increases in low back curve during pregnancy were no more likely to develop back pain. 
- People who work occupations involving frequent awkward postures do not have higher levels of back pain. 
A systematic review done in 2008 that analyzed more than 54 studies on the link between pain and posture has the most compelling evidence dispelling any correlation between posture and various back and neck pain.  The quality of the studies was generally poor, but they were not able to exhibit any association between measurements of sagittal spinal alignment and pain.
The research indicates that, if any correlation exists between posture and pain, it is weak and circumstantial. It may even be the case that pain causes bad posture, and not the other way around, as studies show that people who are injected with a solution causing back pain will unconsciously change their postural strategies. 
The general takeaway is that you shouldn’t spend too much time worrying about trying to change static posture to conform to some normative ideal, as many studies show that it is likely not a factor in back pain. Instead, encourage patients to stay comfortable, keep moving, work to improve function and make sure to use good alignment and form when engaged in strenuous exercise or end range activities. If back pain persists, it may be a good idea to make a physical therapy appointment. For more information about treatment for back and neck pain or to make an appointment click here.
Grundy, Roberts (1984) Does unequal leg length cause back pain? A case-control study. Lancet. 1984 Aug 4;2(8397):256-8.http://www.ncbi.nlm.nih.gov/pubmed/6146810
Pope, Bevins (1985) The relationship between anthropometric, postural, muscular, and mobility characteristics of males ages 18-55. Spine (Phila Pa 1976). 1985 Sep;10(7):644-8.http://www.ncbi.nlm.nih.gov/pubmed/4071274
Grob, Frauenfelder et al. (2007), The association between cervical spine curvature and neck pain. Eur Spine J. 2007 May; 16(5): 669–678.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2213543/
Nourbakhsh, et al. (2002) Relationship between mechanical factors and incidence of low back pain. J Orthop Sports Phys Ther. 2002 Sep;32(9):447-60. http://www.ncbi.nlm.nih.gov/pubmed/12322811
Dieck, et al. (1985) An epidemiologic study of the relationship between postural asymmetry in the teen years and subsequent back and neck pain. Spine (Phila Pa 1976). 1985 Dec;10(10):872-7. http://www.ncbi.nlm.nih.gov/pubmed/2938272
Franklin, et al. (1988) An analysis of posture and back pain in the first and third trimesters of pregnancy. J Orthop Sports Phys Ther. 1998 Sep;28(3):133-8. http://www.ncbi.nlm.nih.gov/pubmed/9742469
Lederman (2010) The fall of the postural–structural–biomechanical model in manual and physical therapies: Exemplified by lower back pain. CPDO Online Journal (2010), March, p1-14.http://www.cpdo.net/Lederman_The_fall_of_the_postural-structural-biomechanical_model.pdf
Christensen, et al. (2008) Spinal curves and health: a systematic critical review of the epidemiological literature dealing with associations between sagittal spinal curves and health. J Manipulative Physiol Ther. 2008 Nov-Dec;31(9):690-714. http://www.ncbi.nlm.nih.gov/pubmed/19028253
Hodges, Moseley (2003) Experimental muscle pain changes feedforward postural responses of the trunk muscles. Exp Brain Res (2003) 151:262–271 http://cdns.bodyinmind.org/wp-content/uploads/Hodges-et-al-2003-Exp-Brain-Res-experimental-lbp.pdf