Week 5 & 6 Material Flashcards
Difference between postural control and balance.
Balance is what you can see, it is the output of our system. Postural control is what is going on in the body to allow balance to be expressed optimally or less optimally; we cannot see how the postural control system works, but we can see if it was effective or ineffective.
Postural Control is…
The ability to control “the body’s position in space for the duel purpose of stability and orientation.”
What is Horak’s definition of Postural Control?
Postural control results from the complex interaction among many body systems that work cooperatively to control both orientation and stability of the body.
Horak’s definition of Postural Control is grounded in which of the following theories?
Systems Model of Motor Control
What are the primary structures involved in the mediation of postural control?
Visual, vestibular, proprioceptive, somatosensation, MSK, cognitive/attention, and memory.
When the task, the environment, and the person are all interacting at an optimal level, that individual can be…
Stable, if the task demands stability or if it requires the individual to rearrange in space, they can do so and have mobility and stability.
What is orientation?
Alignment of body segments relative to the task.
What is stability?
Can be tasks that require you to remain being still or stable, standing or sitting.
What is stability during mobility?
Tasks like walking, remain stable while you are moving through space.
What is posture?
Posture describes the biomechanical alignment of body segments to the body’s orientation in space.
What is postural stability?
Balance or the ability to control the COM within the BOS.
Define BOS.
All points of the body that touch the surface, and the area defined by those points.
Define COM. Does it change or remain the same throughout life?
The point in the body that is the center of the body’s total mass. COM changes with growth and development. In adults, the COM is low compared to a child’s because their head is the heaviest part of their body; thus, the infant will have a higher COM.
Define COG.
The vertical projection of the COM.
Define COP.
The center of the distribution of the total force applied to the support surface. COP continually moves around the COM/COG.
What is postural sway? Does this change or remain the same throughout life?
It can occur in any posture, and you are never still. In standing, the amount of sway is minimal, but it is task and environment-dependent. This will change with growth and development; in children, the amount of sway is greater, and it decreases as the child learns to walk.
As a child begins to stand and walk, where will their COM be? By 3-4?
It should be just above the level of the umbilicus; it should drop just below the level of the umbilicus.
As a child begins to stand and walk, where will their COM be? By 3-4?
It should be just above the level of the umbilicus; it should drop just below the level of the umbilicus.
As a child begins to stand and walk, where will their COM be? By 3-4?
It should be just above the level of the umbilicus; it should drop just below the level of the umbilicus.
As a child begins to stand and walk, where will their COM be? By 3-4?
It should be just above the level of the umbilicus; it should drop just below the level of the umbilicus.
What is quiet stance?
Static or steady state, we are not moving. If there is postural sway, the individual can use an ankle or hip strategy.
Is ankle strategy in phase or out of phase? Is hip strategy in phase or out of phase?
Ankle: in phase
Hip: out of phase
Explain ankle strategy.
Ankle strategy has the axis of motion at the ankle joint, and the head is moving with the body in the direction of the sway. The whole body is moving as a pendulum from the ankle joint. We think of this as a LEAN.
Difference between ankle strategy when the body leans forward or backward.
As we move forward, our posterior muscles are stretched and act to bring us back. As we move backward, our anterior muscles are stretched and act to bring us back. For both anterior and posterior, the first muscle group to activate will be the most DISTAL and then it will work proximally.
Explain hip strategy.
Hip strategy has the axis of motion at the hip joint. It shows the head moving in a different direction from the rest of the body. As the trunk moves backward, the hips are extended and the trunk is flexed.
Difference between hip strategy when the body leans forward or backward.
As the body leans anterior, the posterior structures will be on stretch. The first muscles to fire will be the abdominals, followed by the quads. As the body leans posterior, the anterior structures will be on stretch. The first muscles to fire will be the paraspinals, then the hamstrings.
If we experience a stronger, more intense stimulus, or if we experience a stimulus that is unexpected and unpredictable, what strategy will be used?
Hip strategy
If we experience a slower, less intense stimulus that is on a firm floor surface and is predictable, what strategy will be used?
Ankle strategy
What are the three strategies that can be used to reorganize your BOS?
Stepping strategies; reaching strategies; and step and reach strategies.
Difference between reaching and stepping strategy.
If it is a reach that you significantly changed your BOS to come into contact with another surface, it is a reach strategy. If it is a step, you moved your BOS, so stepping strategy.
What are the factors that play a role in what we choose for a strategy?
Past experience, the environment, and the amount of displacement.
If you are standing on top of a step stool, what strategy are you most likely going to choose?
Ankle strategy, not hip or stepping strategy.
If you have a small duration perturbation, what strategy will you use?
You will probably use an ankle strategy, not a stepping strategy.
If we are in a narrow stance, what strategy would you use?
Ankle strategy
What is a CPA? APA?
CPA stands for compensatory postural adjustment; they are small, proportionate responses that are regional, rather than full body. APA stands for anticipatry postural adjustments; they work with the CPAs to fine tune the postural control.
