Contact us

Ergo reports




Env. Design




Ergo humor

Search site

About us

File readers


Humanics Ergonomics

Core muscles & posture


Core muscle development & posture

Static core function

  • Anatomy

    Major muscles included are the pelvic floor muscles, transversus abdominis, multifidus, internal and external obliques, rectus abdominis, erector spinae (sacrospinalis) especially the longissimus thoracis, and the diaphragm.

    Minor core muscles include the latissimus dorsi, gluteus maximus, and trapezius.
  • Functions

    The core is used to stabilize the thorax and the pelvis during dynamic movement.
Static movement
  • Function of the static core muscles

    Static core functionality is the ability of one’s core to align the skeleton to resist a force that does not change.
  • Valsalva maneuver

    Core muscles are very important in the Valsalva maneuver, which is when a person’s thorax tightens while holding their breath. This normally involuntary action can be induced by linking one’s hands in front of the chest while standing, and then pulling against the hands without letting go.

    The Valsalva maneuver assists in lifting, excretion, pushing, birthing, and, when uncontrolled, it can lead to stammering or stuttering.
  • Anatomical posture and support

    The core is traditionally assumed to originate most full-body functional movement, including most sports. In addition, the core determines to a large part a person’s posture.

    In all, the human anatomy is built to take force upon the bones and direct autonomic force, through various joints, in the desired direction. The core muscles align the spine, ribs, and pelvis of a person to resist a specific force, whether static or dynamic.
Dynamic core function
  • Dynamic movement & core muscles

    The nature of dynamic movement must take into account our skeletal structure (as a lever) in addition to the force of external resistance, and consequently incorporates a vastly difference complex of muscles and joints versus a static position.

    Because of this functional design, during dynamic movement there is more dependence on core musculature than just skeletal rigidity as in a static situation. This is because the purpose of movement is not to resist a static, unchanging resistance, but to resist a force that changes its plane of motion.

    By incorporating movement, the bones of the body must absorb the resistance in a fluid manner, and thus tendons, ligaments, muscles, and innervation take on different responsibilities. These responsibilities include postural reactions to changes in speed (quickness of a contraction), motion (reaction time of a contraction) and power (amount of resistance resisted in a period of time).
  • For example...

    When walking on a slope, the body must resist gravity while moving and balancing itself on uneven ground. This forces the body to align the bones in a way that balances the body while at the same time achieving momentum through pushing against the ground in the opposite direction of the desired movement.

    At first it may seem that the legs are the prime movers of this action, but without balance, the legs will only cause the person to fall over. Therefore, the prime mover of walking is achieving core stability, and then the legs move this stable core by using the leg muscles.

    When the slope is slippery, the person needs to be able to react and catch themselves in order to maintain balance. This is a function of how quickly a person’s muscles can react to the situation, a measure of their quickness and speed (how fast they react and how quickly they can recruit the necessary muscles). A person who can react quickly but not recruit their muscles quick enough will know they are falling, but not be able to do anything about it. A person who cannot react quickly enough (or appropriately) but can recruit their muscles with quickness, will be jerky and over-react easily.

    Finally, assuming the subject has reacted in time and with speed, they must have the power to accept their body’s weight, since slipping reduced the load on their muscles, however brief. This ability of the muscles to have power, will make sure that the immediate load can be taken by the muscles and they will be able to restore balance and, hopefully, achieve their goal


Please see original version from Wikipedia on Core Muscles.

See Wikipedia’s review on the Valsalva Maneuver.

See Wikipedia on the Human anatomy   |   Skeleton   |   Muscles   |   Nervous system


Posture tools  |  Keyboards  |  Seating  |  Anthropometrics  |  Vision  |  Humor

Work ergonomics  |  Workplaces  |  Products  |  Ergonomics Assoc.  |  Standards

Ergonomics  |  Children  |  Disabled  |  Env Design  |  Medical  |  Science  |  Legal

Projects  |  Clients  |  Presentations  |  Publications  |  About us  |  Reach us


Certificant, Board of Certification in Professional Ergonomics

Reach us Privacy & Copyright Valid Ergonomics XHTML 1.0 Transitional
©Humanics Ergonomics