Gait & Motor Activation

Question 1

Why is walking efficient and smooth?

Answer 1

• 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 2

Receiprocal Inhibition induces muscular on & off cycles

Answer 2

• reciprocal inhibition is governed at the spinal cord level
• the system is created by a stimulus (activation and reciprocal inhibition)
• occurs across muscle groups in both limbs
• allows for an on and off cycle of muscle activation
• allows flexibility
• a mechanism to govern motor function
• reciprocal inhibition occurs with activation of muscular contraction-prevents agonist and antagonist activation

Question 3

Example of Reciprocal Inhibition

Answer 3

Terminal Swing

Ankle: anterior tibialis is activated. Gastroc/soleus is not activated. This allows ankle dorsiflexion not to be impeded. Allows for optimal joint function through dorsiflexion

Question 4

An example of Muscular Co-activation

Answer 4

Two opposing muscular groups activate to stabilize a joint or to improve accuracy.

In terminal stance:
* Quadriceps are concentrically contracting
* Hamstrings are eccentrically controlling knee extension
* Purpose is to control, decelerate down the knee extensor activity & absorb ground shock

Question 5

Neurobiology of Gait: Central Pattern Generators

Answer 5

• Brain to SC
• SC coordinates the on and off timing of motor activity during walking
• controlled by CPG’s in SC
  -controls limb segements
  -ipsilaterally and contralaterally

How the CPG works:
* Combination of sensory or feedback (touch, pressure from environment & forces within the muscle) to provide feedback to the pattern formation and provide motor activity.
* The sensory input adjusts the rhythm and walking pattern.
* Rhythmic network method of activating muscle groups or motor pools of flexors and extensors.

Question 6

Muscular activation in walking

Answer 6

• Muscular activation is organized by swing phase (flexors) & stance phase (extensors). Generation of force emerges from stance phase.
• The timing of the muscle groups is a rhythmical and speeds up or slows down based upon the individual’s pace.
• Muscle activation pattern is similar across the human species

Question 7

Loading response & midstance and quadriceps & gastroc-soleus (sagittal plane)

Answer 7

• Loading response: shock absorption-quadriceps eccentric
• Midstance: gastroc-soleus in late midstance and controls the forward advancement of the tibia. Tibia advances over fixed foot. Quadriceps are inactive.

Question 8

Midstance Frontal Plane Activation

Answer 8

• Gluteus medius provides frontal plane stability at the hip
• TFL provides stability (coactivation for stability) across hip and knee
• Hip stability is needed during loading response and midstance.