Topic 1 - Introduction to Movement

Question 1

Passive Movement

Answer 1

Movement resulting from forces that are external to the body

Ex. Gravity, supportive devices, another body

Question 2

Active Movement

Answer 2

Movements resulting from muscular contractions

• passive movements can lead to active movements (ex. Stretch reflex)

Question 3

Reflex Action

Answer 3

Involuntary

Stereotyped response to specific stimulus

Amp of response = amp of stimulus

Question 4

Voluntary Action

Answer 4

Response that is a result of high-order cognitive processing

Result of a flexible & variable neural network

Question 5

Characteristics of reflex action

Answer 5

Short latency

Stereotyped (you can predict response based on stimulus)

Conscious awareness does not lrocede response

Involuntary

Response determined by stimulus

Innate (born with reflex response)

Generally protective in purpose

Question 6

Characteristics of voluntary action

Answer 6

Longer latency

Not stereotyped (adaptable/ can be novel)

Conscious awareness before response

Voluntary

Response related, but not determined by stimulus

Learned (not innate)

Can be protective or harmful

Question 7

3 other types of actions (not relfexice or voluntary)

Answer 7

1. Fixed-action pattern
2. Preprogrammed responses
3. Rhythmic motor patterns

Question 8

Fixed-Action Pattern

Answer 8

Not in humans, typically in invertebrates

Relatively stereotyped… fixed latency behaviour triggered by a stimulus

Innate

Amp of response not related to amp of stimulus

Response sometimes not related to stimulus

Question 9

Preprogrammed Responses

Answer 9

Voluntary actions stored in the CNS and then triggered by a stimulus
(Driving car example.. start-react effect)

Shorter latency than voluntary responses but longer than true reflexes

Amp of responses no relayed to amp of stimulus

Actions sometime not related to stimulus

Question 10

Rhythmis Motor Patterns

Answer 10

Initiated and temrinated with boluntary command

Once initiated, sequence of contractions are relatively stereotyped and continue in an almost automatic (involuntary) manner

• ex gait locomotion when walking
• once you start walking things begin to feel automatic

Question 11

Cognitive/reduction Approach to Understanding Movement

Answer 11

Whole is equal to the sum of the parts

Function is derived from understanding the characteristics of the elements

Once you understand individual elements, you can understand whole system

Ex. Compare person with lesion to certain brain area to someone without lesions and compare performance

Question 12

3 parts of sensation to action loops

Answer 12

1. Sensory receptor (PNS)
2. Integration (CNS)
3. Effectir (PNS)

Question 13

Feedback Loop (9)

Answer 13

1. Sensory receptors and nerves (PNS)
2. Stimulas ID (CNS)
3. Response selection (CNS)
4. Response programming (CNS)
5. Motor Plan
6. SC (CNS)
7. Peripheral Nerve (PNS)
8. Muscles
9. Action/Output

Question 14

What 2 systems generate a feedback loop?

Answer 14

1. Proprioceptive system (from muscle)

2. Visual system (from eyes)

Question 15

3 parts of executive functioning

Answer 15

1. Stimulus ID
2. Response selection
3. Response programming

Question 16

4 rules of a Motor Unit

Answer 16

1. Each MU has one MN
2. One MN innervates many muscle fibres
3. Each muscle fibre is innervatee by only one MN
4. Only one kind of muscle fibre per MU

Question 17

3 types of extrafusal fibres innervated by alpha MNs

Answer 17

1. Slow twitch (type 1)
2. Fast twitch fatigue resistant (type II a)
3. Fast twitch fatigable (type II b)

Main contributer to movement / muscle force

Question 18

Intrafusal and gamma MN fxn

Answer 18

Role in adjusting sensitivtynof muscles spindles, activation of intrafusal fibre does not lead to muscle force generation

• proprioception
• stretch reflex

Question 19

During voluntary movements, are both alpha and gamma MNs activated?

Answer 19

Yes

Question 20

Why are slow Twicth fibres (I) recruited first?

Answer 20

1. Smaller components
   - smaller cell bodies mean less synaptic output needed to reach action potential threshold
2. Slower transmission
3. Small contraction force bc they are smaller muscles fibres
4. Slower contraction speed

Question 21

Why are fast fatigable (IIb) recruited last

Answer 21

1. Larger components
   - bigger cell bodies need more synaptic inlut to reach threshold
2. Faster nervous transmission
   - larger diameter means faster transmission
3. Fast contraction speed
4. Larger contraction force bc larger muscles

Question 22

3 burst of Triphasic EMG

Answer 22

1. Agonist (prime mover)
   - initial burst to start the movement
2. Antagonist
   - burst to slow down movement as gosl location is approached
3. Agonist
   - burst to finish the movement

Question 23

Concentric contraction

Answer 23

AGONIST muscle length decreases

Question 24

Eccentric Contraction

Answer 24

AGONIST muscle length increases

Question 25

Isometric contraction

Answer 25

Agonist muscle length doesn’t change Triphasic EMG pattern present

Question 26

Isotonic contraction

Answer 26

Agonist muscle length may or may not change… force contraction kept constant No triphase EMG

Question 27

2 principles of Force generation

Answer 27

1. Order of receuitment (size principle) | 2. Force-force variability relationship

Question 28

Force-force variability relationship

Answer 28

How well you can produce a target force over and over again Greater variability when aiming for higher peak force (greater % of max voluntary contraction)

Question 29

Why do you get a distribution in peak force?

Answer 29

System noise Leads to error in recruitment Random electrical signals that leas to recruitment of random MUs

Question 30

Size principle

Answer 30

Size of the MU recruited (combined eith system noise) leads to variability in peak force generation