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CSB523- Gait > wk 7 - muscle movements > Flashcards

wk 7 - muscle movements Flashcards

1
Q

what does the iliospoas do

A

hip flexor

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2
Q

glute max/med

A

hip abductors

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3
Q

bicep femoris

A

hip extensor, knee flexor

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4
Q

rectus femoris

A

hip flexor, knee extensor

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5
Q

gastrocnemius

A

knee flexor, ankle plantar flexor

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6
Q

tibialis anterior, extensor digitorum longus, extensor hallucis longus

A

dorsiflexor

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7
Q

soleus

A

ankle plantar flexor

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8
Q

fibularis longus

A

plantar flexor, evertor of the foot

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9
Q

muscle contracttion types

A

concentric- shortening against load
eccentric- lengthening under load
ismetric- maintaining constant legnth against load

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10
Q

sites of common lesions affecting gait include

A
  1. motor cortex (stroke, head injury)
  2. UMN (spinal cord injury)
  3. anterior horn cell (polio)
  4. peripheral nerve (nerve injury)
    5.musle (muscle dystrophy)
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11
Q

muscle fibre types

A

Type I (slow twitch)
* Low to moderate force over long periods
* Aerobic metabolism
* Fatigue resistant

  • Type IIB (fast twitch)
  • Higher forces generated
  • Glycolytic metabolism
  • Easily fatigued
  • Type IIA
  • Properties intermediate between Type I and Type IIB
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12
Q

what does EMG do?

A

EMG measures the electrical activity of a contracting
muscle (the muscle action potential at the motor unit)

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13
Q

types of EMG electrodes? (2)

A
  1. surface electrodes
    fixed to the skin overlying the
    muscle
    * Can pick up muscle action
    potentials from many (superficial)
    motor units
    * Not appropriate for deep
    muscles
    * Interference from adjacent
    muscles (“cross-talk”
  2. fine wire electrodes
    inserted into the muscle belly using a needle
    can be painful/invasive
    signal comes from small region of a muscle so correct placement is crucial
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14
Q

EMG parametres (5)

A
  • Peak activity (magnitude usually expressed as %MVC)
  • Time to peak (seconds)
  • Average activity (magnitude usually expressed as %MVC)
  • Onset/offset times (% gait cycle)
  • Duration of muscle activity (% gait cycle)
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15
Q

adductor longus

A

hip adductor

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16
Q

understand power generation during the gait cycle

A
17
Q

discuss the role of individual muscles during the gait cycle

A
18
Q

reliability (ICC) what does it tell us

A

closer to 1 is the most reliable

above 0.9 is excellent
above 0.7 is good

19
Q

repeatability (RC) tells us what

A

the greater the change, the more clinically significant the findings are??????

20
Q

interpreting and understanding research paratmeters/ reliability/ repeatability - IN EXAM

A
21
Q

What can’t the EMG do and what do the signals depend on?

A

cannot differentiate between concentric, eccentric and isometric contractions but tells us when the muscle switches on and switches off (muscle activity)

EMG signal depends on length-tension relationship of muscle.

EMG activity does not affect force output. higher EMG activity does not mean the force production has increased (not linear)

22
Q

joint power analysis for EMG tells us what

A

power analysis can differentiate between eccentric, concentric loading of ankle plantarflexors

23
Q

joint moment for EMG tells us what

A

only tells us a simple version of joint moments occuring ???????

24
Q

understand what power analysis - in exam for research paper

A

eccentric followed by concentric movement. ankle plantarflexors and dorsiflexors

25
Q

what is power (formula, in joint terms, units)

A

p= force x velocity

power (watts) = moment (Nm) x angular velocity (radians per second or degrees per second)

26
Q

power exchange during gait cycle and reference to type of muscle contractions

A

kinetic and potential energy

power exchanges take place across the hip, knee and ankle joints throughout the gait cycle (swapping between kinetic energy and potential energy-stored)`

-concentric muscle contraction: power is generated
-eccentric: absorbs power
-isometric: no power exchange takes place

same occurs with ligaments not just muscles

27
Q

during initial contact what power flow occurs in the limb

A

impact with the floor, absorbs the power of the limb, eccentric contraction (dorsifexors)

28
Q

during midstance what power flow occurs in the limb

A

flow reverses and leg power increases due to power generation at the ankle (plantar flexors)

29
Q

after toe off what power flow occurs

A

more power flows through the hip joint (hip flexors working during swing phase, hip extensors working after it)

30
Q

what happens in the ankle during loading response, midstance and terminal stance

A

Ankle dorsiflexors restrain foot slap eccentrically (power absorption)

plantarfleors control forward momentum of the tibia eccentrically (power absorption)

plantarflexors raise heel concentrically (power generation)

31
Q

at initial contact what muscles are involved and where is the ground reaction force located for the hip/knee/ankle

A
  • Simultaneous activity of knee extensors
    and flexors
    – stabilise and position knee
  • Hip extensors decelerate thigh (glute max)
    – drives knee extension
  • Tibialis anterior eccentric contraction
    – eases foot to floor
    – prevents foot slap

GRF anterior to hip, posterior to knee and ankle

32
Q

loading response what muscles involved? + GRF

A
  • Weight acceptance
    – controlled collapse
    – knee spring (quads & vasti)
  • tiny bit of Ankle plantarfexion (eccentric)
    – allows CoP to move forward
    – shifts reaction force of body anterior at
    the knee
    – thus aids knee extension
  • Gluteus medius contracts (isometric)
    – stabilises pelvis (frontal plane)

GRF: anterior to hip, posterior to knee, anterior to ankle

33
Q

midstance muscles involved + GRF

A

Controlled lengthening of soleus
– keeps foot/forefoot “pressed’ to ground
– allowing shank to lean forward

  • Minimal muscle activity
    – body is “falling” forward
    – has momentum and kinetic energy

GRF: posterior to hip, anterior to knee and ankle

34
Q

terminal swing + GRF

A
  • Ankle plantarflexors
    – concentric contraction
    – accelerates body forward
    (This burst of activity is responsible for
    most of the power generation which
    occurs in walking)
  • Iliopsoas
    – Small burst of activity
    – Leads unloading process of pre-swing

GRF: posterior to hip, anterior to knee, anterior to ankle

35
Q

pre swing and initial swing + GRF

A

Hip flexors (iliopsoas & rectus femoris)
– concentric contraction
– starts to lift femur
– starts to swing limb forward

  • Limb is like a passive pendulum
    – pendulum swing is regulated by the
    way the limb is flexed (moment of
    inertia)
  • Tibialis anterior gives foot ground clearance

GRF: posterior to hip, posterior to knee, anterior to ankle

36
Q

terminal swing + GRF

A

Hamstring contraction
– eccentric and/or isometric
– controlled slowing of shank
– energy transfer to hip & pelvis

  • Ankle
    – Tibialis anterior changes to eccentric
    contraction
    – Foot finely adjusted in preparation for
    initial contact

GRF: anterior to hip, posterior to knee and ankle

37
Q

most muscle activity is active when?

A

active at the start and end of swing

minimal activity in mid stance (switch off)

accelerates and decelerate movements

38
Q

know your reference for degrees during gait

A

10% peak dorsiflexion terminal swing
60% knee flexion during swing

etc

CSB523- Gait (12 decks)

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