Term
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Definition
| base of support = contact with ground |
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Term
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Definition
| center of gravity = mass at one point where line of gravity pulls straight down |
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Term
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Definition
| center of pressure = line where COG meets the ground |
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Term
| what produces external moments |
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Definition
| external forces: gravity, inertia, ground reaction force |
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Term
| what produces internal moments |
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Definition
| internal forces: muscles, ligaments, joint contact forces |
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Term
| what information do we get from muscle spindles |
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Definition
| instantaneous muscle length AND rate of change of muscle length |
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Term
| what information do we get from golgi tendon organs |
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Definition
| tension and rate of change of tension in tendon |
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Term
| where are extrafusal muscle fibers |
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Definition
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Term
| what innervates extrafusal muscle fibers |
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Definition
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Term
| where are intrafusal muscle fibers |
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Definition
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Term
| what innervates intrafusal muscle fibers |
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Definition
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Term
| what are the names of the 2 types of sensory endings that come out of the muscle spindle |
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Definition
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Term
| what is anothter name for primary? |
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Definition
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Term
| what is another name for secondary |
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Definition
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Term
| what do primary/group 1a sensory signals tell us? |
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Definition
| how the length of the muscle is changing |
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Term
| what do group 2 sensory signals tell us? |
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Definition
| instantaneous length of muscle |
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Term
| where do group 1a and 2 sensory signals go? |
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Definition
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Term
| what does gamma motor neuron do? |
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Definition
| tell intrafusal fibers when to contract and relax |
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Term
| when the muscle is stretched, how does the firing of impulses change? |
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Definition
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Term
| when the muscle is unstretched, how does the firing of impulses change? |
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Definition
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Term
| what is the input into a muscle spindle? |
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Definition
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Term
| what are the outputs of the muscles spindle? |
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Definition
| group 1a dynamic and group 2 static fibers (axons that go to spinal cord) |
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Term
| example of monosynaptic stretch reflex |
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Definition
| hammer on quads tendon causes quick stretch to muscle |
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Term
| what happens in a monosynaptic stretch reflex? |
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Definition
| 1a primary fiber respons by sending signal up to spinal cord where it synapses on alpha motor neuron. Alpha motor neuron returns to extrafusal muscle fibers and makes them contract |
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Term
| how many efferent fibers are gamma motor fibers? |
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Definition
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Term
| what happens when a Ia response goes to spinal cord? |
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Definition
| it will tell alpha neuron to contract muscle |
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Term
| how do gamma efferents modify sensitivity of spindle? |
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Definition
| contraction of gammas increaes sensitivity to stretch; relaxation of gamas decreases sensitivity to stretch |
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Term
| what is the afferent signal that comes from golgi tendon organ? |
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Definition
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Term
| what do group 1b fibers tell us |
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Definition
| static AND dynamic tension in tendon |
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Term
| what is the function of the golgi tendon organ |
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Definition
| inhibit the muscle that is contracting. |
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Term
| where are golgi tendon organs |
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Definition
| located in series with 10-15 muscle fibers at the myotendonous junction |
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Term
| does the golgi tendon organ have a dynamic or static response? |
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Definition
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Term
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Definition
| free to use upper extremities for other tasks |
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Term
| disadvantages of being bipedal |
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Definition
| increased stress on vertebra/pelvis/lower extremeties; reduced stability from reduced BOS |
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Term
| goals of postural control |
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Definition
| control the body's orientation In space, maintain COM within BOS, stabilize head with respect to vertical, do these things with minimal energy expenditure |
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Term
| where is LOG at ankle in standing |
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Definition
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Term
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Definition
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Term
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Definition
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Term
| where is LOG at head in standing posture |
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Definition
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Term
| what muscles produce internal moment to overcome external moment of gravity at head |
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Definition
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Term
| where is LOG at hip in standing |
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Definition
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Term
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Definition
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Term
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Definition
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Term
| what produces internal moment at hip |
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Definition
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Term
| where is LOG at knee in standing |
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Definition
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Term
| what is the external moment at the knee |
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Definition
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Term
| what is the internal moment at the knee |
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Definition
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Term
| what provides internal moment at knee |
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Definition
| passive support from posterior capsule |
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Term
| what provides internal moment at ankle |
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Definition
| plantarflexion from soleus |
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Term
| what can someone with paraplegia do to stand? |
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Definition
| if someone can't produce an active internal flexion moment, they can use the external extension moment from the posterior LOG along with passive internal "flexion" from iliofemoral ligament |
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Term
| describe forward head posture |
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Definition
| large external flexion moment causes large internal extension moment. Cervical extensors are overworked and lengthened. |
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Term
| how does spine change in anterior pelvic tilt |
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Definition
| anterior pelvic tilt causes increased lumbar lordosis and increased thoracic kyphosis |
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Term
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Definition
| lumbar lordosis, thoracic kyphosis |
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Term
| where is LOG in swayback posture |
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Definition
| farther posterior to hip joint |
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Term
| where are ligaments stressed in swayback posture |
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Definition
| anterior hip to prevent external flexion moment |
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Term
| why do hip extensors become weak in swayback posture? |
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Definition
| reliance on anterior hip ligaments leads to disuse atrophy of hip extensor muscles |
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Term
| where is LOG of knee in flexed knee posture? |
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Definition
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Term
| what is the external moment at the knee in flexed knee posture |
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Definition
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Term
| what is the internal moment at the knee in flexed knee posture? |
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Definition
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Term
| what provides interal extension moment at knee in flexed knee posture? |
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Definition
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Term
| how does flexed knee affect other LE jionts? |
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Definition
| flexed knee causes hip to flex and dorsiflexes ankle. This causes shortening of hip flexors => flexed hip posture |
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Term
| what causes genu recurvatum? |
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Definition
| quads weakness, diminished dorsiflexoin |
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Term
| where is the LOG in normal knee standing posture? |
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Definition
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Term
| what opposes external extension moment at knee? |
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Definition
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Term
| what is the result of genu recurvatum on the posterior capsule of the knee? |
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Definition
| gets worse as it continues to stretch posterior capsule |
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Term
| If I am standing and I pick up my left foot, what happens to my LOG? |
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Definition
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Term
| If I am standing and I pick up my left foot, what happens to my center of pressure? |
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Definition
| moves completely under right foot |
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Term
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Definition
| low arch, flat foot, pronated |
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Term
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Definition
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Term
| in relaxed sitting, where is LOG? |
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Definition
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Term
| in slumped sitting, where is LOG |
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Definition
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Term
| what tissues support us during slumped sitting |
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Definition
| passive tissues for support; ligaments hold you up against external flexion |
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Term
| is pelvic tilted anteriorly or posteirorly in standing? |
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Definition
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Term
| how is lumbar lordosis affected in standing? |
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Definition
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Term
| is pelvic tilted anteriorly or posteriorly in sitting? |
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Definition
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Term
| how is lumbar spine affected by sitting |
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Definition
| flattens; decreased lumbar lordosis with posterior pelvic tilt |
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