Problems with excessive pelvis posterior tilt

Pelvic alignment influences the spine position, respiratory function and muscle tone. The are many articles that discuss about malalignment of the pelvis, but only a few focus on excessive pelvis posterior tilt. Thus, the article is to add more information about this topic.

If you find yourself dealing with “low-back pain”, “poor posture”, “chest tightness”, “unable to breath smoothly”, “calf muscle tightness”, then the article might be suitable for you.

What is pelvis posterior tilt/ rotation?

Pelvis posterior rotation during sitting is that you “sit” on your coccyx or tail bone. The figure below shows the pelvis is rotated in an anti-clock direction. This alignment often appear in sitting in a deep sofa or sitting with your legs on the bench. During standing, pelvis posterior tilt happens when the knees are hyperextended.

Subsequences of excessive pelvis posterior tilt/ rotation

Thoracic spine alignment

The most evident change is the curvature of the T spine. The sacrum tilts posteriorly during pelvis posterior rotation, leading to a compensatory kyphotic spine (hunch back). This may put stress or pressure to the anterior proportion of the spine body, a study reported that the lower T spines (T8–12) receive the most pressure.

Figure 3: The figure is from Kinesiology of the Musculoskeletal System 3rd Edition Foundations for Rehabilitation。This shows the changes of spine alignment during pelvis posterior tilt.

Rib mobility

Rib mobility decreases when the spine is hyper-kyphotic. During breathing, the upper and middle ribs move forward and outward; the lower ribs move outward. The range of motion of the ribs decrease in a kyphotic posture, which lead to tightness in the chest area.

Figure 4: The change of spine curvature leads to a different breathing pattern.

Respiratory functions

According to research, excessive pelvic posterior rotation influence the respiratory system. The rib mobility decreases due to spine kyphosis, leading to decreased lung expansion. The vital capacity, respiratory flow are significantly decreased in those with excessive pelvis posterior rotation.

Cervical/ neck alignement

The changes are evident in figure 3. The head and neck are protruded (or forwarded) due to the increased curvature of the thoracic and lumbar spine. This often combines symptoms such as neck pain, migration or myofascia pain syndrome .

Changes in muscle tone

Excessive pelvis posterior tilt during sitting stretches and lengthens the low back muscles while loosens/ shortens the abdominal muscles and hip flexors.

Pelvis posterior tilt during standing may lead to hamstring and calf muscle tightness. In addition, the quads may be over-activated due to hyperextended knees.

Figure 5: changes of muscle tone

How can I correct my pelvis?

The easiest way is to start from sitting.

  1. Sit on a stool and put your hands under your bottom.

2. Rock your pelvis forward and back to find your sit bones (ischial tuberosity). You will feel hard and sharp once you find them.

3. Remain your hands on the sit bones and rock the pelvis forward and back to put most of your body weight on the tuberosity. (You will feel the most evident contour of the sit bones.)

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References

Aramaki Y., Kakizaki F., Kawata S., Omotehara T., Itoh M. Effects of the posterior pelvic tilt sitting posture on thoracic morphology and respiratory function. J Phys Ther Sci 2021 Feb;33(2):118–24.

Neumann DA., Roen KE. Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation 3rd edition.

物理治療師 女性運動與姿勢矯正 physiotherapist, MS, CES