Posture 1 Posture can be either Static or

Posture 1

Posture can be either: Static or Dynamic

In static posture the body and its segments are aligned and maintained in certain positions Such as in Standing Lying Sitting

In dynamic posture the body and its segments are moving Such as in Walking Running Jumping

The base of support is an area bounded posteriorly by the tips of the heels and anteriorly by a line joining the tips of thee toes When there is a smaller base of support, there is less stability

The human’s center of gravity (COG), is located within the body approximately at the level of the second sacral segment When the center of gravity is higher, there is less stability

Postural control is a person’s ability to maintain stability of the body segments in response to forces that threaten to disturb the body’s structural equilibrium

Maintenance and control of posture depends on the integrity of: 1 - Central nervous system 2 - Visual system 3 - Vestibular system 4 - Musculoskeletal system 5 - The input from receptors in and around joints, ligaments and tendons

The external forces on the body and body segments are 1 - Inertia 2 - Gravity 3 - Ground reaction forces

The internal forces on the body and body segments are produced by muscle activity and passive tension in ligaments, tendons, joint capsules, and other soft-tissue structures

For the body to be in equilibrium, the sum of all forces acting on the body and its segments bust be equal to 0

Inertial Forces Inertial forces are ignored in static posture because there is a little or no acceleration occurring

Inertial Forces Inertial forces must be considered in all postural analysis of all dynamic postures such as walking or running

Gravitational Forces Gravitational forces act downward from the body's center of gravity

Gravitational Forces In the static erect posture the body’s COG falls within the base of support

Gravitational Forces In the dynamic posture such as walking the body’s COG falls outside of the borders of the feet during a large portion of the activity

Ground Reaction Forces Ground reaction forces are the forces that act on the body as a result of interaction with the ground