What is flat back posture

Back shapes - hollow back, rounded back and flat back

The spine consists of 24 free vertebral bodies, which are divided into three body regions: 7 cervical vertebrae, 12 thoracic vertebrae and 5 lumbar vertebrae. The spine continues downwards with two so-called "fused vertebrae": the sacrum originally consisted of 5 individual vertebrae, the coccyx usually of 4 individual vertebrae, which are fused to form a synostosis. Between the vertebral bodies are the intervertebral discs, which serve as a buffer in the event of vibrations. In side view, the spine is shown in a double S-shape.
The body structure of a person is just as individual as the person himself. The body curvature of the spine, defined as a norm, will therefore only be found in a few people without any deviation. The most common variants in addition to the normal posture are the "rounded back" (thoracic hyperkyphosis) and the hollow back (kyphosis-lordosis). Another variant is the flat back.

Hollow back (lordotic posture)

When viewed from the side, the classic view of the hollow back is as follows: The thoracic spine shows an increased convex curve (hyperkyphosis), while the lumbar spine develops a reinforced concave curve (hyperlordosis). This changed statics of the back can affect adjacent joints and the spine itself:

  • Pelvic tilt forward
  • Increased thrust on the lowest vertebrae
  • Danger of degeneration of the facet joints (these are formed by the articular processes of two vertebrae lying on top of each other)

This posture weakens muscles because, among other things, they do less holding work.

  • Rectus abdominis muscle (straight abdominal muscle)
  • M. obliquus externus abdominus (external oblique abdominal muscles)
  • Gluteus maximus muscle (gluteus muscle)
  • Mm. ischiocrurales (hamstring muscles)

In addition, the following muscles shorten and tense through this posture:

  • M. erector spinae (back extensor, especially lumbar region)
  • M. iliopsoas (hip flexor muscle)
  • Mm. adductores (muscles of the inner thighs)

Hunchback (kyphotic posture)

The description of the rounded back can already be derived from the name. In side view, the thoracic spine is excessively rounded, which means that the upper body and shoulders are inclined forward. If the cervical spine were to follow the movement, the view would continue to move towards the ground day after day. To avoid this, the person affected stretches their head up and covers the cervical spine backwards. The shoulders also move forward, which means that the shoulder blades are spread apart from the torso.
A hunched back can disturb the overall statics, which can lead to uneven loading of the intervertebral discs.
Not only the statics are affected, the muscles are also inactive or shortened and tense due to this unphysiological posture. The following muscles are less active:

  • M. erector spinae (back extensor)
  • M. trapezius Pars ascendens / transversa (lower and middle part of the hood muscle)
  • M. deltoideus Pars spinalis (posterior part of the shoulder muscle)
  • M. teres minor, M. infraspinatus (external rotators in the shoulder joint)

The following muscles shorten or tense due to poor posture:

  • M. trapezius pars descendens (upper part of the hood muscle)
  • M. obliquus capitis & M. rectus capitis posterior (posterior neck muscles)
  • M. pectoralis major / minor (chest muscles)
  • Rectus abdominis muscle (straight abdominal muscle)

Flat back (hypolordotic posture)

In the side view, the flat back is characterized by the fact that the spine has only a very slight curvature. This causes the head to be pushed up and the pelvis tilted backwards. The pelvic tilt has an impact on the sacroiliac joint (SIJ), as the spring action between the joint and the vertebrae is limited. This leads to increased power transmission to the intervertebral discs.
Since the flat back deviates from the physiological double S curve of the spine, this back shape also has a weakening effect on the muscles.

  • M. erector spinae (back extensor, especially lumbar region)
  • M. iliopsoas (hip flexors)
  • M. rectus capitis anterior (anterior cervical flexors)

This form also shortens and tightens the muscles. The following muscles are traditionally affected:

  • Mm. ischiocrurales (hamstring muscles)
  • Rectus abdominis muscle (straight abdominal muscle)


The treatment is initially based on the individual problem. If there are specific back problems, the first thing to do is to provide pain relief and relief. In general, the aim of treatment for all back shapes is to create improved posture and muscular balance. Muscular shortening and tension should be eliminated through mobilization and stretching exercises. Targeted exercises from the back school serve to improve posture and more even load on the musculoskeletal system. The inactive core muscles should be activated.

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