L3 Muscular Activation Patterns

Question 1

function of muscle coactivation

Answer 1

stabilize joint by activating agonist and antagonist

Question 2

functions of eccentric contraction

Answer 2

shock absorption, deceleration, control

Question 3

reciprocal inhibition
function in gait

Answer 3

contracts agonist, allowing joint to move freely without antagonist activating
induce muscular on and off cycles

Question 4

How do humans have a smooth and efficient walk?

Answer 4

spinal cord delivers muscle activation in finely tuned on and off signals
genetic blueprint
years of practice; taking about 9 years to develop an adult walking pattern

Question 5

What principle prevents co contraction of TA and soleus in gait?

Answer 5

reciprocal inhibition

Question 6

What principle keeps terminal stance phase stable (quads and hamstrings)?

Answer 6

co contraction
helps control and decelerate, absorb shock while hitting the ground

Question 7

central pattern generators

Answer 7

patterned movement coming from the brain to the spinal cord
spinal cord coordinating on and off timing in gait through CPGs in spinal cord to control limbs ipsilaterally and contralaterally
uses sensory and muscle feedback to provide motor activity and adjust rhythm as needed

Question 8

in which gait phase does the most propulsion happen?

Answer 8

stance phase

Question 9

main muscle groups active in swing phase (flexor/extensor)

Answer 9

flexors

Question 10

main muscle group active in stance phase (flexor/extensor)

Answer 10

extensors

Question 11

initial contact muscle activation: hip knee ankle

Answer 11

hip: glut max, adductor magnus (prepare loading response)
knee: quads (extend knee)
ankle: TA, eccentric control
goal: control lowering foot

Question 12

loading response muscle activation: hip knee ankle

Answer 12

hip: glut max and adductor magnus
knee: eccentric quads to absorb shock
ankle: pretibial muscles eccentric control, peak TA activity

Question 13

midstance muscle activation: hip knee ankle

Answer 13

hip: glut max, glut med for stability; TFL stability
knee: quads, dynamic knee stability
ankle: soleus and gastroc eccentric control of tibia movement forward

Question 14

What muscle groups control tibial movement in loading response vs midstance phases of stance?

Answer 14

loading response: control comes from eccentric quads, once tibia moves over foot gastroc/soleus eccentric control controls tibial movement

Question 15

frontal plane stability of the hip is controlled by what muscle?

Answer 15

glut med
keeps hip from dropping more than 4 degrees
plus TFL

Question 16

terminal stance phase muscle activation: hip knee ankle

Answer 16

gait propulsion
hip: not a ton important
knee: no quad activation, biceps femoris active to prevent knee extension
ankle: peak gastroc soleus activity to prevent tibial collapse and propulsion forward

Question 17

pre swing muscle activation: hip knee ankle

Answer 17

hip: adductor longus - hip flexion along w quads preparing for swing phase
knee: gracilis prepares knee flexion
ankle: gastroc soleus activity stops

Question 18

initial swing muscle activation: hip knee ankle

Answer 18

hip: iliacus active in a big burst then inactive, sartorius ans gracilus peak activity
knee: biceps femoris short, sartorius, gracilis peak to flex knee
ankle: EDL and EHL dorsiflex, peak activity, TA active through this phase and mid swing

Question 19

mid swing muscle activation: hip knee ankle

Answer 19

carry momentum
hip: gracilis carries momentum
knee: extension through momentum and start to decelerate motion
ankle: pretibial muscles active to carry momentum

Question 20

terminal swing muscle activation: hip knee ankle

Answer 20

hip: hamstring peak activity
knee: quads concentric for knee extension, increasing step length
ankle: pretibial muscles concentric contraction to prepare for dorsiflexion in initial contact