Gait and Motor Activation

Question 1

Terms to describe muscular activation during gait (6)

Answer 1

Isotonic: length change in muscle
Concentric/Eccentric
Reciprocal inhibition: allows joint to freely move w/o antagonist activating
Co-activation: simultaneous contraction of agonist and antagonist muscle groups work to stabilize the joint
Muscular synergies: groups of muscles across joints that work together to perform activity

Question 2

Why is walking efficient and smooth?

Answer 2

• muscular activity is delivered at the spinal cord level during routine walking
• genetic blueprint and years of training
• finely tuned on and off muscular activation

Question 3

Where is reciprocal inhibition governed and what does it do?

Answer 3

• Reciprocal inhibition is governed at the spinal cord level
• induces muscular on and off cycles
• it allows for flexibility and a mechanism to govern motor function

Question 4

When does reciprocal inhibition occur?

Answer 4

It occurs with activation of muscular contraction and it prevents the agonist and antagonist activation

Question 5

What are some examples of reciprocal inhibition during terminal swing?

Answer 5

At the ankle the TA is activated and the gastroc/soleus is not. This allows for dorsiflexion not to be impeded and for optimal joint function.

Question 6

Describe what you would see in an EMG of the TA and Soleus.

Answer 6

We would see an example of reciprocal inhibition; where the soleus is in a period of high activity, the TA would be in a period of little to no activity,

Question 7

Give an example of muscular co-activation during terminal swing.

Answer 7

In muscular co-activation two muscle groups activate simultaneously. Ex. the quads concentrically activate while the hamstrings are eccentrically contracting to control knee extension. The purpose is to control, decelerate down the knee extensor activity and absorb ground shock.

Question 8

Where are central pattern generators located and what do they do?

Answer 8

• CPG’s are in the spinal cord (the spinal cord coordinates the on and off timing of motor activity during walking)
• It controls limb segments ipsilaterally and contralaterally
• CPGs are a rhythm network
• A method of activating muscle groups or motor pools of flexors/extensors

Question 9

How does the CPG work?

Answer 9

• Combination of sensory feedback to provide feedback to pattern formation and provide motor activity
• Sensory input adjusts the rhythm and walking pattern

Question 10

In which phase is muscular activation organized?

Answer 10

Organized by swing (flexors) and stance (extensors) phase.

Question 11

In which phase does generation of force emerge from?

Answer 11

Force emerges from stance phase

Question 12

T/F Muscle activation pattern is different across the human species

Answer 12

FALSE: muscle activation pattern is similar across the human species

Question 13

What occurs across the hip, knee, and ankle during initial contact?

Answer 13

• Hip: glute max and adductor mag. are active in prep for loading response
• Knee: quads extend the knee, hamstrings contract to counteract contact torque
• Ankle: TA eccentric control along with the pretibial musculature

Question 14

What occurs across the hip, knee, and ankle during loading response?

Answer 14

Hip: lower fibers of glute max and adductor mag, and hamstrings are activated to counteract the flexor torque. Peaking are TFL, glue med and min, upper fibers of glute max are used to stabilize the frontal plane
Knee: eccentric quad activity to absorb shock, diminished hamstring activity
Ankle: eccentric contraction of pretibial muscles (EHL, EDL, TA), peak TA activity, TP stabilizes throughout stance phase,

Question 15

What occurs across the hip, knee, and ankle during mid stance?

Answer 15

Hip: gluteus max upper fibers, glute med provides stability in the frontal plane, TFL provides stability (co-activation for stability)
Knee: quads provide dynamic knee stability until midstance eccentric
Ankle: gastroc-soleus restrains/controls the tibia which allows forward progression of the tibia

Question 16

Loading Response v Midstance

Answer 16

LR: Quads on, tibia advancement, shock absorption at quads
MS: Quads off and Gastroc/Soleus on, tibia advances over fixed foot

Question 17

Which muscle provides stability during midstance in the frontal plane?

Answer 17

• the glute med at the hip
  -TFL across the hip and knee!!

Question 18

What occurs across the hip, knee, and ankle during terminal stance?

Answer 18

Hip: TFL anterior fibers activate while posterior ceases
Knee: no quad activity, w/ bicep femoris activation to prevent knee extension
Ankle: gastroc-soleus peaks in activity to prevent tibial collapse (provide propulsion); TP, fibularis brev/longus stabilizes,

Question 19

In which phase does the muscular activation of the gastroc peak?

Answer 19

-During terminal stance

Question 20

What occurs across the hip, knee, and ankle during pre-swing phase?

Answer 20

Hip: adductor longus contributes to flex the femur w/ rectus femoris
Knee: gracilis preps for knee flexion
Ankle: gastroc soleus ceases activity early in pre-swing

Question 21

What occurs across the hip, knee, and ankle during initial swing?

Answer 21

Hip: iliacus initial phase and stops, sartorius and gracilis peak in activity, hammies come in late
Knee: bicep femoris SH, sartorius, and gracilis peak to flex knee
Ankle: EDL and EHL show peak activity, TA continues to mid swing

Question 22

What occurs across the hip, knee, and ankle during midswing phase?

Answer 22

Hip: carries on motor activity from initial swing with gracilis carrying momentum
Knee: carries knee extension through momentum, hammies begin to decelerate the momentum
Ankle: pretibial are active and carries momentum

Question 23

What occurs across the hip, knee, and ankle during terminal swing phase?

Answer 23

Hip: hamstrings peak at their activity, glute max/adductor mag stabilize the hip
Knee: quads are concentrically activating
Ankle: pretibial muscles are concentrically active