L1.1 - 1.2 - Gait

Question 1

What 2 do humans tends to use?

Answer 1

Humans tend to use walking (inverted pendulum walk) and running (impulsive run).

Question 2

Comparing net cost of transport for humans and bipedal chimpanzee? Why are humans more efficient?

Answer 2

Humans = 10 times more efficient

Chimps don’t keep their centre of gravity over their point of contact

Question 3

Torque

Answer 3

Twisting force required for joint to move

Question 4

Humans: torque at hip, knee and ankle

Answer 4

Not much at hip and knee but a lot at ankle

Question 5

In Chimpanzees, where is there most joint toque during locomotion?

Answer 5

Hip

Question 6

From highest to lowest: Contact time for Chimp quad, chimp bipedal and humans

Answer 6

Quad, humans, bipedal

Question 7

Increased signals from (which brain structure) increases locomotor rate and triggers gait pattern transition

Answer 7

Brainstem

Question 8

Cerebellum is devoted to somatosensory/motor

Answer 8

Motor control

Question 9

In which vertebrae region is locomotion related to (where the pattern generating circuit is found)

Answer 9

Lumbar Sacral Region

Question 10

Henneman’s size principle:

Answer 10

Small motor units are recruited before larger motor units

Question 11

Muscle spindle

• What are they?
• What do they do if gait is inefficient?

Answer 11

• stretch/length detector
• negative feedback regulation of muscle length by muscle spindles
• If gait is inefficient, muscle spindle activity can bring forward the gait cycle

Question 12

Describe the alternating flexor/extensor pattern

Answer 12

When an excitatory interneuron activates an extensor motor neuron, an inhibitory interneuron inhibits the flexor motor neuron.

Question 13

What kind of gait is trotting?

Answer 13

Diagonal gait

Question 14

What area of the brain is involved in voluntary movements?

Answer 14

Basal ganglia and cerebrum

Question 15

Parkinson’s Disease is caused by?

Answer 15

Death of dopamine-generating cells in the substantia nigra

Question 16

Parkinson gait

Answer 16

Stooped posture, short shuffling steps, turning by small increments (pedestal turning), tremor in upper extremities

Question 17

Huntington gait is caused by?

Answer 17

Neurodegeneration of basal ganglia - leads to increased size of ventricles

Question 18

Huntington gait

Answer 18

Interrupted rhythm of steps, wobbles from side to side upsetting balance, stiff arms (doesn’t swing as patient uses it to maintain balance)

Question 19

Cerebellum (makes us less clumsy)

Answer 19

• Coordinating the timing and sequence of muscle actions
• Muscle tone
• Motor learning
• Planning complex movements

Question 20

Ataxia

Answer 20

lack of voluntary coordination of muscle movements

Question 21

Ataxia gait

Answer 21

walks with legs far apart, unstable, tendency to fall during tandem walk

Question 22

Circumducting gait? Upper or lower neuron signal

Answer 22

Upper, cannot fully flex knee, hip or ankle, swings leg laterally while rotating his pelvis to the opposite side to allow patient’s foot to clear the ground, characteristic of someone with weakness of one leg

Question 23

Hemiparetic gait? Upper or lower neuron signal

Answer 23

Upper, (stroke in right cerebral hemisphere) left knee and ankle are stiff due to spasticity that follows loss of the descending flexor biased motor tracks, swing left leg, left elbow, wrist and fingers are flexed (sign of spastic weakness in upper extremity)

Question 24

Describe impulsive run

Answer 24

Bouncing from one leg to another

Question 25

Golgi tendon organ

-What effect does it have during locomotion?

Answer 25

force detector
During locomotion, golgi tendon organs signalling load during walking (extensors bearing weight) have an excitatory effect on extensor motorneurons to maintain stability

Question 26

Electromyography - what does it measure

Answer 26

Signals when muscle is active

Question 27

Start of swing phase - F/E?

End of swing phase - F/E?

Answer 27

F

E

Question 28

Start and end of Stance phase - F/E?

Answer 28

E

Question 29

Which phase is the overlap in electromyography activity found, where F and E occur at the same time?

Answer 29

At the end of the swing phase