neuromuscular system

Question 1

What is the automatic nervous system?

Answer 1

Regulates involuntary movement. We do not consciously think about our movement - it happens automatically

Question 2

what is the neuromuscular system

Answer 2

Movement of muscle controlled by the brain. nervous system and muscles work together to produce movement

Question 3

What are the two components of the nervous system and their functions

Answer 3

sympathetic - speeds up (prepares for exercise)
parasympathetic - slows down ( slows down high energy functions)

Question 4

Name the three types of muscle fibre

Answer 4

1a - slow oxidative
2a - fast oxidative glycotic
2b - fast glycotic

Question 5

order the types of muscle fibres from slowest - fastest twitch

Answer 5

1a -> 2a -> 2b

Question 6

Name a sporting example that uses 1a fibres and why its approriate

Answer 6

marathon running -

suited to endurance
low force produced
harder to tire

Question 7

Name a sporting example that uses 2a fibres and why its appropriate

Answer 7

Teams games

require a mixture of anaerobic and aerobic movements
medium resistance to fatigue (compared to 2b)

Question 8

Name a sporting example that uses 2b fibres and why its appropriate

Answer 8

javelin / hammer- throw/ sprint

highly prone to fatigue
high anaerobic capacity (doesnt require oxygen)

Question 9

How are our muscle fibres determined? How can we change them

Answer 9

Genetically - we cannot change them, only develop them through training

Question 10

What is a functional characteristic? Name 3

Answer 10

what the muscle type does / how it behaves

contraction speed
fatigability
Aerobic/anaerobic capacity

Question 11

What is a structural characteristic? Name 3

Answer 11

When it can be physically seen using a microscope

Mitochondrial density
capillary density
glycotic enzyme activity

Question 12

what are the effects of training on muscle fibre types?

Answer 12

Fibres are genetically determined
however training increases size of fibres (hypertrophy)

Question 13

How many types of fibres are found in a motor unit?

Answer 13

1

Question 14

what transmits a nerve impulse from the brain to the motor unit?

Answer 14

Neuromuscular junction

Question 15

How do motor units vary depending on type of contraction needed?

Answer 15

fine contractions - eg eye muscles - have smaller motor units

gross contractions eg quads/hamstrings - have larger motor units to provide a larger and
more forcefull contraction

Question 16

What is the ALL OR NOTHING LAW

Answer 16

a sequence of impulses have to be pass “threshold” to stimulate ALL the muscle fibres in a motor unit, otherwise one contract

Question 17

How do you increase strength of contraction

Answer 17

The brain recruits different muscle fibre types dependent on type of contraction. For example brain will recruit fast twitch motor units (2a +2
b) for big contractions vice versa

Question 18

What is wave summation?

Answer 18

where there is a repeated nerve impulse with no time to relax so a smooth, sustained contraction (tetanic contraction) occurs rather than small twitches

Question 19

What is spatial summation?

Answer 19

when the strength of a contraction occurs by altering the number and size of motor units contracting - reducing fatigue in aerobic endurance activities

Question 20

Explain how wave summation allows a gymnast to gain the height requires for a jump in a floor routine

Answer 20

Allows muscle to be stimulated again before it relaxes
resulting in a singular tetanic contraction
a gymnast would be able to have a larger and more powerful contraction in their legs
giving them more height off the ground

Question 21

What does PNF stand for

Answer 21

proprioceptive neuromucular facilitation

Question 22

What is PNF?

Answer 22

an advanced stretching technique that is carried out using CRAC (contract - relax- antagonist - contract)
increasing flexibility by pushing the limb further each time

Question 23

What is a tetanic contraction

Answer 23

A sustained muscle contraction caused by a build up of a series of fast repeated stimuli during wave summation

Question 24

How can a performer vary the strength of muscular contractions to ensure that a skill is completed correctly (4 marks)

Answer 24

1) the greater the force needed, the more motor units are required
2) larger motor units can be used
3) Spatial summation used - meaning units wont fatigue as quickly
4) All or nothing law means that muscle units can only contract when they reach a threshold impulse, meaning different sizes of units can contract dependent on the size of contraction

Question 25

What 2 proprioceptors are involved in PNF?

Answer 25

Golgi tendon organs
Muscle spindles

Question 26

Explain the role of Muscle spindles in PNF

Answer 26

Muscle spindles detect the lengthening of a muscle and initiate a stretch reflex tot he CNS.
This prevents the muscle from overstretching and possibly tearing
This impulse causes the muscle to contract preventing the muscle from being lengthened more

Question 27

Explain the roles of Golgi Tendon organs in PNF

Answer 27

Detect levels of tension in the muscle and release an autogenic inhibition. This inhibition overrides the stretch reflex allowing the antagonist to lengthen and relax

Question 28

Define Isometric Contraction

Answer 28

when there is tension in the muscle whilst stationary with no visible movement