The neuromuscular system (P1)

Question 1

What are the three main types of muscle fibre?

Answer 1

. Slow oxidative/slow twitch (type I)
. Fast oxidative glycolytic (type IIa)
. Fast glycolytic (type IIb)

Question 2

Explain slow twitch fibres (type I)?

Answer 2

Slow contraction speed which means it is better adapted to lower intensity exercise such as long distance running.

Question 3

Explain fast twitch fibres (typeII) generally?

Answer 3

Fast contraction speed and provide a strong force of contraction. They also fatigue quickly and are only used for short, intense bursts of effort. Most of the energy is provided anaerobically.

Question 4

Explain fast oxidative glycolytic fibres (type IIa)

Answer 4

less resistant to fatigue (than type IIb) so are used for events such as 1500m where a longer burst of energy is needed.

Question 5

Explain fast glycolytic fibres (type IIb)

Answer 5

Fatigue much quicker and used for highly explosive events such as 100m.

Question 6

What is the contraction speed(m/s), motor neurone size, motor neurone conduction capacity, force produced, fatigability, mitochondrial density, myoglobin content, capillary density, aerobic capacity, anaerobic capacity, myosin ATPase capacity in relation to type I fibres?

Answer 6

slow(110), small, slow, low, low, high, high, high, very high, low, low

Question 7

What is the contraction speed(m/s), motor neurone size, motor neurone conduction capacity, force produced, fatigability, mitochondrial density, myoglobin content, capillary density, aerobic capacity, anaerobic capacity, myosin ATPase capacity in relation to type IIa fibres?

Answer 7

fast (50), large, fast, high, medium, medium, medium, medium, medium, high, high

Question 8

What is the contraction speed(m/s), motor neurone size, motor neurone conduction capacity, force produced, fatigability, mitochondrial density, myoglobin content, capillary density, aerobic capacity, anaerobic capacity, myosin ATPase capacity in relation to type IIb fibres?

Answer 8

fast (50), large, fast, high, high, low, low, low ,low, very high, very high

Question 9

How can muscle fibre size be increased through training?

Answer 9

Muscular hypertrophy.

Question 10

What is a motor unit?

Answer 10

A motor neurone and its muscle fibres

Question 11

What is a motor neurone?

Answer 11

Nerve cells which transmit the brain’s instructions as electrical impulses to the muscles.

Question 12

What is the neuromuscular junction?

Answer 12

Where the motor neurone and muscle fibre meet.

Question 13

What is the all or none law?

Answer 13

Where a sequence of impulses has to be of sufficient intensity to stimulate all of the muscle fibres in a motor unit in order for them to contract. If not, none of them contract.

Question 14

What ways can be used to increase the strength of contraction?

Answer 14

wave and spatial summation

Question 15

What is wave summation?

Answer 15

When there is a repeated nerve impulse with no time to relax so a smooth, sustained contraction occurs , rather than twitches. Produces a tetanic contraction.

Question 16

What is spatial summation?

Answer 16

When the strength of a contraction changes by altering the number and size of the muscle’s motor units.

Question 17

What is PNF?

Answer 17

Proprioceptive neuromuscular facilitation is an advanced stretching technique

Question 18

What are muscle spindles and golgi tendon organs?

Answer 18

Types of proprioceptors

Question 19

What are muscle spindles?

Answer 19

These detect how far and how fast a muscle is being stretched and produce the stretch reflex. Found between skeletal muscle and tendons.

Question 20

What are golgi tendon organs?

Answer 20

These are activated when there is tension in the muscle. Found between muscle fibre and tendons.

Question 21

Briefly explain the first part of the CRAC technique of PNF?

Answer 21

Muscle is stretched until tension is felt. A stretch reflex will occur if it is being stretched too far.

Question 22

Briefly explain the second part of the CRAC technique of PNF?

Answer 22

Individual isometrically contracts for a least ten minutes by pushing a muscle against a resistance. the golgi tendon organs detect the tension in the muscle and are activated and their inhibitory signals override the excitory signals by the muscle spindles. delaying the stretch reflex.

Question 23

Briefly explain the third part of the CRAC technique of PNF?

Answer 23

The leg is lifted again like part 1 but can be pushed further because the golgi tendon organs have caused the antagonist to relax so the leg can stretch further.