1.1 Muscle types, fibers and recovery rates

Question 1

What is skeletal muscle?

Answer 1

muscles attached to the skeleten which can o ly contract when stimulated by an electrical impulse sent from the central nervous system

Question 2

What are motor neurones?

Answer 2

specialised cells which transmit never impulses rapidly to a group of muscle fibres.

Question 3

What is the motor unit?

Answer 3

a motor neuron and the muscle fibres stimulated by its axon

Question 4

What is an action potential?

Answer 4

positive electrical charge inside the nerve and muscle cells which conducts the nerve impulse down the neuron and into the muscle fibre

Question 5

What is the place where the axons motor end plates meet the muscle fibre

Answer 5

neuromuscular junction

Question 6

What is the synaptic cleft?

Answer 6

a small gap between the motor end plates and muscle fibre

Question 7

An action potential cannot cross the synaptic cleft without a ?

Answer 7

neurotransmitter called acetylcholine

Question 8

Where is the neurotransmitter located and why?

Answer 8

secreted in synaptic cleft to help nerve impulses across the gap

Question 9

What does an action across the synaptic cleft cause?

Answer 9

wave of contraction down the muscle fibre (muscle contraction)

Question 10

What is the all or none law?

Answer 10

when an action potential that reaches a threshold charge, all muscle fibres within the motor unit will contract at the same time and with maximum force. If the action potential does not reach the threshold charge, none of the muscle fibres will contract

Question 11

Give the flow diagram of the role of a motor unit?

Answer 11

1. nerve impulse initiated in the motor neuron cell
2. nerve impulse conducted down the axon of the motor neuron by a nerve action potential to the synaptic cleft
3. neurotransmitter called acetylcholine is secreted into the synaptic cleft to conduct the nerve impulse across the gap
4. If the electrical charge is above a threshold, muscle fibre will contract
5. happens in an all or non fashion

Question 12

What is the strength of contraction dependent on?

Answer 12

the number of motor units recruited by the brain

Question 13

The greater the number of motor units recruited the greater … ?

Answer 13

the force of contraction

Question 14

What are the three types of muscle fibres?

Answer 14

• slow oxidative (SO)
• fast oxidative glycolytic (FOG)
• Fast glycolytic (FG)

Question 15

What are slow oxidative muscle fibres?

Answer 15

a type of muscle fibres rich in mitochondria, myoglobin and capillaries which produces a small amount of force over a long period of time

Question 16

What are fast glycolytic muscle fibres?

Answer 16

type of muscle rich phosphocreatine which produces a maximal force over a short period of time

Question 17

What are fast glycolytic muscle fibres?

Answer 17

structurally designed to work anaerobically, with large stores of phosphocreatine for rapid energy production and the largest amount of force. (fatigue quickly)

Question 18

What is phosphocreatine?

Answer 18

high energy compund stored in the muscle cell used as a fuel for very high intensity energy production

Question 19

WHat are mitochondria?

Answer 19

structure in the sarcoplasm responsible for aerobic energy production

Question 20

What is myoglobin?

Answer 20

a protein in the muscle responcible for transporting oxygen to the mitochondria

Question 21

What does aerobic work mean?

Answer 21

low, intensity long duration exercise in the presence of oxygen

Question 22

What does anaerobic work mean?

Answer 22

high intenisity, short duration excersise without oxygen

Question 23

Which sports have a high percentage of slow oxidative fibres?

Answer 23

endurance athletes: marathon, triathlon, cross-country skiing

Question 24

Which sports have a high percentage of fast oxidative glycolytic fibres?

Answer 24

high intensity athletes:
800m-1500m run
200m freestyle swim

Question 25

Which sports have a high percentage of fast glycolytic muscle fibres?

Answer 25

explosive athletes:
60-100m sprinting
Javelin
long jump

Question 26

What are the 5 structural characteristics of slow oxidative fibres?

Answer 26

Size: small
Fibres per neuron: few
Mitochondria density: hight
Capillary density: high 
Myoglobin content: high

Question 27

What are the 5 structural characteristics of fast oxidative glycolytic fibres?

Answer 27

Size: large 
Fibres per neuron: Many
Mitochondria density: moderate 
Capillary density: high 
Myoglobin content: Moderate

Question 28

What are the 5 structural characteristics of fast glycolytic fibres?

Answer 28

Size: large
Fibres per neuron: Many
Mitochondria density: low
Capillary density: low 
Myoglobin content: low

Question 29

What are the 5 functional characteristics of slow oxidative fibres?

Answer 29

Speed: slow
Force of contraction: low 
Fatigue resistance: High 
Aerobic capacity: High
Anaerobic Capacity: Low

Question 30

What are the 5 functional characteristics of fast oxidative glycolytic fibres?

Answer 30

Speed: Fast 
Force of contraction: high 
Fatigue resistance: moderate  
Aerobic capacity: moderate 
Anaerobic Capacity: moderate

Question 31

What are the 5 functional characteristics of fast glycolytic fibres?

Answer 31

Speed: fast
Force of contraction: high 
Fatigue resistance: low 
Aerobic capacity: low
Anaerobic Capacity: high

Question 32

Explain how to maximise aerobic training to maximise slow oxidative fibres?

Answer 32

1:1 or 1:05 work to rest ratio. -running

Question 33

How are fast glycolytic fibres recruited?

Answer 33

near muscular failure

Question 34

Explain how to maximise fast glycolytic fibres when working?

Answer 34

1:3 work to rest ratio

3-5 mins rest with just 2-6 reps

Question 35

Explain the recovery for weight training (optimising fast glycolytic fibres)

Answer 35

take 4-10 days to recover. leave a minimum of 48 hours before re-working the muscle