Postural Control: Adults

Front 1

center of mass`

Back 1

-center of the total body mass found by calculating the weighted average location of all the mass in a body

Front 2

center of gravity

Back 2

-vertical projection of the COM

Front 3

base of support

Back 3

-area of the body in contact w/ the support surface

Front 4

center of pressure

Back 4

-point location of the weighted average of all the downward forces acting on the area in contact w/ the ground

Front 5

postural control

Back 5

-the ability to control the body's position in space for stability and orientation

Front 6

postural orientation

Back 6

-alignment of the body and alignment of the trunk and head w/ respect to gravity, support surfaces, and objects in the environment

Front 7

postural stability

Back 7

-balance
-the ability to control the center of mass relative to the base of support

Front 8

limits of stability

Back 8

-the sway boundaries in which the individual can maintain the COM w/in the BOS w/o having to change the BOS
-vary based on the task, individual biomechanics, and environment

Front 9

ROM/flexibility

Back 9

-degree of movement available influences control

Front 10

muscle performance

Back 10

-strength, power, endurance (fatigue)
-ability to produce and respond w/ appropriate force at the appropriate rate for the amount of time required

Front 11

sensation

Back 11

-position and motion of the body and body parts relative to each other
-using muscle spindle & GTOs, joint receptors, skin mechanoreceptors for touch, pressure, vibrations, proprioception, and kinesthesia

Front 12

ROM and aging

Back 12

-loss of ROM
-loss of spinal flexibility
-altered posture (Shift of COM toward heels)
-w/ disease or pathology: arthritis, osteoporosis, pain
-contribute to loss of functional reach, altered balance strategies, and slower walking

Front 13

sarcopenia

Back 13

-age related muscle wasting

Front 14

motor unit changes and aging

Back 14

-# of motor units decline
-# of muscle fibers per motor unit increases = giant motor units
-functional consequences of loss of strength and power are evident in postural control of balance, sit-to-stand, stair climbing, and walking

Front 15

3 sensory processing systems used for perception of body orientation in space

Back 15

-visual
-vestibular
-somatosensory

Front 16

visual

Back 16

-position of head relative to environment
-orientation of head to maintain level gaze
-direction and speed of head movements

Front 17

vestibular

Back 17

-position and movement of the head w/ respect to gravity and inertial forces
-angular acceleration of the head
-linear acceleration and head position relative to gravity

Front 18

somatosensory

Back 18

-proprioceptive, joint, and cutaneous receptors
-position and motion of the body relative to the BOS
-position and motion of body parts relative to each other
-fastest system for processing rapid responses

Front 19

sensory weighting hypothesis

Back 19

-each sense provides a unique contribution to postural control

Front 20

sensory systems and aging

Back 20

-decline in vibratory, tactile, and pressure sensation
-requires greater reliance on vision and vestibular systems which are slower than somatosensory responses

Front 21

vision decline w/ age

Back 21

-threshold for detecting minimum light to see an object increases
-loss of peripheral vision
-decline in visual acuity
-decline in visual contrast

Front 22

vestibular system decline w/ age

Back 22

-greater difficulty when there is conflict b/t vision and somatosensory info
-greater problems w/ open environments (less reliable reference system, dizziness is more common, unsteadiness)
-small responses to balance disturbances

Front 23

motor responses and aging

Back 23

-older adults have slower onset latencies in key muscles w/ disturbances
-show differences in sequencing of muscles
-tend to coactivate muscles around a joint more often than young (stiffen the joints)
-tend to use hip movements more often than ankle movements to correct balance

Front 24

feedforward control

Back 24

-preselection of muscles in advance of a movement
-based on previous experience

Front 25

central set

Back 25

-the state of the nervous system that is influenced by the context of as task
-previous experience
-instructions given
-optimize the responses quickly under new conditions