Lecture 9: Gait Flashcards
what are the 2 phases in gait
Stance Phase (foot
on floor)
Swing Phase (foot
in air)
what are the 5 parts of the stance phase
- Initial contact (heel strike)
- Load response (foot flat)
- Midstance (single-leg stance)
- Terminal Stance (heel off)
- Pre-swing (toe-off)
what are the 3 parts of the swing phase
- Initial swing (acceleration)
- Mid-swing
- Terminal swing
(deceleration)
what are the 3 Important Power Events during Walking
- Hip extension power during initial contact
- Ankle plantar flexion power from terminal stance to pre-swing
- Hip flexor power at end of pre-swing
what are the 2 gait parameters
spatial parameters (how we move)
temporal parameters (time)
what are Central Pattern Generators
spinal cord and brainstem circuits responsible for programmed, rhythmic movements
Circuits for chewing, swallowing, and breathing are located where
in the brainstem
Circuits for locomotion
are located where
in the spinal cord
CPGs can be what 3 things
- Spontaneously active and rhythmic (respiration)
- Triggered by a specific sensory stimulus (swallowing)
- Voluntary and triggered by higher motor centres (locomotion)
is locomotion just reflexes
no its more.
The timing of the different muscle contractions is complex and fast
what did we learn from animal locomotion studies
Each limb has its own CPG
At specific times, signals are sent to LMNs for flexor muscles and at other times, signals are sent to LMNs for extensor muscles
what happens with CPGS in the absence of defending control and sensory input
CPGs can produce rhythmic but slightly clumsy movements
what are the 2 Mechanisms of Rhythm Generation
pacemaker networks
Reciprocal Inhibition
what are Pacemaker Networks
A neuron acts as an oscillator that drives other neurons into a rhythmic pattern
what is Reciprocal Inhibition
2 neurons reciprocally inhibit each other
what 3 things do we know about CPGs in humans
Newborns demonstrate stepping despite not having mature descending tracts
Rhythmic involuntary movements observed in people with SCI
Epidural spinal cord stimulation can induce stepping movements in people with SCI
where do we think Locomotion CPGs are likely located
the lower thoracic and lumbar regions of the spinal cord
do humans or animals rely more on supraspinal influences than other animals
humans
What is are the 5 role/function of supraspinal input?
Activates spinal CPGs
Controls intensity of CPGs
Maintains equilibrium during locomotion
Adapts limb movements to external conditions
Coordinates locomotion with other motor behaviours
where is the Control region for locomotion is located
the reticular formation in the caudal pons and medulla –the mesencephalic locomotor region (MLR)
↑ intensity of mesencephalic locomotor region (MLR) stimulation results in what
increased gate speed
MLR important for which 3 things
gait initiation, modulation, and termination
what are the 3 important Supraspinal Inputs
Sensory and motor cortices ( complex tasks need more activation)
cerebellum (timing and posture)
basal ganglia (initiating and stopping movement)
what is the role of interneurons in CPGs during the stance phase
- CPG interneuron1 activates extension LMNs
- Collaterals to
interneuron 2 inhibit CPG interneuron 3 (flexor LMNs)
do CPGs adapt
yes to the task and environment
how can CPGs be modulated by sensory feedback
Sensory feedback is critical to modifying CPGs
walking in sand cans we need to change the way we walk
what are the 4 steps to how CPGs work
Supraspinal influences activate and modulate CPGs
Oscillators (pacemakers) synchronize interneuron networks responsible for stance or swing
LMNs innervate muscles responsible for locomotion
Sensory feedback modulates CPGs
is there a connection between cognitive impairment and gait speed
a reduction in gate speed happens about 10 years before cognitive ability declines
how is grey matter connected with gait speed
lower volume of gray matter in brain = slower gait speed and smaller gait length
what are Dual Task Paradigms
the concurrent performance of two tasks that can be performed independently, measured separately, and have distinct goals
Poor dual task performance is associated with dementia and
falls
what are the 5 gait deviations with age
Shortened step length
Decreased step width
Decreased velocity
Increased variability (each steps look different)
Increased stance and double support time
what are the 4 Gait Deviations in strokes
Knee hyperextension in stance phase
Poor heel strike
Ataxic gait (wide base of support, unsteady)
Hemiparetic gait (slow, wide base of support, hip circumduction)
what do we see in gait with people with parkensons
freezing gait (very small, shuffling steps)
what is the key priority for stroke survivors
walking
what is the Key physical impairment in stroke
muscle weakness/paresis
what is walking asymmetry after stroke
- Spatial and temporal asymmetries
- Decreased cadence
- Shorter stance time and longer swing time of more affected limb
- Shorter step length of less affected limb
what is Body weight-supported treadmill training (BWSTT) post stroke
very small increases walking velocity and endurance
No improvements among those not walking independently at the start of treatment
- Does not increase the chance of walking independently
Which of the following responses is true regarding Central Pattern Generators?
Signals are sent to flexors to initiate the stance phase
Signals are sent to the extensors to initiate the swing phase
Signals are sent to flexors to initiate swing phase
Signals are sent to flexors to initiate swing phase
How many Central Pattern Generators would a dog have?
4
Which of the following activities would be considered a cognitive-motor dual task activity?
Walking while holding a cup of water
Tapping your foot while drawing a star
Sitting still while counting backwards
Putting on a sock while naming all of the pieces of clothing you might find in a closet
Putting on a sock while naming all of the pieces of clothing you might find in a closet
Why do humans rely more on supraspinal inputs for locomotion than other animals?
We have higher postural control demands than animals
