neuromuscular system Flashcards
What is the automatic nervous system?
Regulates involuntary movement. We do not consciously think about our movement - it happens automatically
what is the neuromuscular system
Movement of muscle controlled by the brain. nervous system and muscles work together to produce movement
What are the two components of the nervous system and their functions
sympathetic - speeds up (prepares for exercise)
parasympathetic - slows down ( slows down high energy functions)
Name the three types of muscle fibre
1a - slow oxidative
2a - fast oxidative glycotic
2b - fast glycotic
order the types of muscle fibres from slowest - fastest twitch
1a -> 2a -> 2b
Name a sporting example that uses 1a fibres and why its approriate
marathon running -
suited to endurance
low force produced
harder to tire
Name a sporting example that uses 2a fibres and why its appropriate
Teams games
require a mixture of anaerobic and aerobic movements
medium resistance to fatigue (compared to 2b)
Name a sporting example that uses 2b fibres and why its appropriate
javelin / hammer- throw/ sprint
highly prone to fatigue
high anaerobic capacity (doesnt require oxygen)
How are our muscle fibres determined? How can we change them
Genetically - we cannot change them, only develop them through training
What is a functional characteristic? Name 3
what the muscle type does / how it behaves
contraction speed
fatigability
Aerobic/anaerobic capacity
What is a structural characteristic? Name 3
When it can be physically seen using a microscope
Mitochondrial density
capillary density
glycotic enzyme activity
what are the effects of training on muscle fibre types?
Fibres are genetically determined
however training increases size of fibres (hypertrophy)
How many types of fibres are found in a motor unit?
1
what transmits a nerve impulse from the brain to the motor unit?
Neuromuscular junction
How do motor units vary depending on type of contraction needed?
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
What is the ALL OR NOTHING LAW
a sequence of impulses have to be pass “threshold” to stimulate ALL the muscle fibres in a motor unit, otherwise one contract
How do you increase strength of contraction
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
What is wave summation?
where there is a repeated nerve impulse with no time to relax so a smooth, sustained contraction (tetanic contraction) occurs rather than small twitches
What is spatial summation?
when the strength of a contraction occurs by altering the number and size of motor units contracting - reducing fatigue in aerobic endurance activities
Explain how wave summation allows a gymnast to gain the height requires for a jump in a floor routine
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
What does PNF stand for
proprioceptive neuromucular facilitation
What is PNF?
an advanced stretching technique that is carried out using CRAC (contract - relax- antagonist - contract)
increasing flexibility by pushing the limb further each time
What is a tetanic contraction
A sustained muscle contraction caused by a build up of a series of fast repeated stimuli during wave summation
How can a performer vary the strength of muscular contractions to ensure that a skill is completed correctly (4 marks)
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
What 2 proprioceptors are involved in PNF?
Golgi tendon organs
Muscle spindles
Explain the role of Muscle spindles in PNF
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
Explain the roles of Golgi Tendon organs in PNF
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
Define Isometric Contraction
when there is tension in the muscle whilst stationary with no visible movement
