Normal posture Flashcards
ability to control COM in relationship to BOS
postural stability
- key variable controlled by CNS during postural control
Vertical projection of the COM
COG
how is COM location determined?
by finding the weighted average of the COM of each body segment
The area of the body that is in contact with the support surface
BOS
The center of the distribution of the total force applied to the supporting surface
COP
- Continuously moves to maintain COM within BOS to maintain balance
- you will either fall or may have to counter if COP moves outside the BOS
Requires orientation & stability, though the interaction of the two will vary based on the task and the environment; involves controlling the body’s position in space for the dual purposes of stability and orientation
postural control
- fundamental to everything we do
What systems interact to achieve postural control?
- Musculoskeletal components
- NM synergies
- individual sensory systems
- Sensory strategies
- Anticipatory mechanisms
- adaptive mechanisms
- internal representations
Results from a complex interaction among many bodily systems that work cooperatively to control both orientation and stability of the body; Determined by the functional task and the environment it is performed in
postural control
- according to systems approach
What does anticipatory control require?
Requires modification of sensory input and motor response to changing task and environment requirements
What are the types of strategies for postural control?
- sensory
- sensorimotor
- attentional
Type of postural control strategy that reflects the rules for coordinating sensory and motor aspects of postural control
sensorimotor
type of postural control strategy that determines how much attention a task requires to maintain postural control
attentional
what are the components of the sensory strategy for postural control?
- Visual
- Somatosensory
- Vestibular
Tone assists in maintaining upright posture to prevent collapsing due to the effect of gravity upon the body. What are the three components tone contributes to postural control?
- Intrinsic Stiffness - hypertonic vs hypotonic
- Background Tone - Exists in all muscles due to neural contribution; soleus and ant tib are “on” in quiet standing for postural sway
- Postural Tone - Activation of antigravity muscles during quiet stance
Both ankle and hip strategies are always present with a fixed BOS, but one predominates dependent on sensory information and task demands. When would the ankle vs hip strategy be used?
- Ankle Strategy
- Occur with low frequency perturbation (<1 Hz)
- More refined movement - Hip Strategy
- Occur with high frequency perturbation (>1 Hz)
- Larger movement
* *Fixed BOS**
