3.1.1.4 Neuromuscular system

Neuromuscular system

Interaction between the nervous and muscular system that enables movement, coordination and force

Slow twitch fibres (Type 1)

Aerobic, slow contraction speed, high fatigue resistance, low force production, high capillary density. High mitochondria density (more sites for ATp resynthesis), High myoglobin content (oxygen in muscle breakdowns glucose for ATP resynthesis without lactate), High triglyceride stores (lower intensities of the race)

Fast oxidative glycotic (Type 2A)

Medium aerobic capacity, moderate fatigue resistance, fast contraction, large force produced

Fast glycolotic (Type 2X)

Fast contraction, fatigue rapidly, Greatest force produced, large motor neurone (greater impulse for larger contraction). High PC stores (faster ATP resynthesis) High glycogen stores (fuel for anaerobic glycolytic energy system), High levels of ATpase breakdown ATP faster

Motor unit

A motor neurone and it’s muscle fibres

Motor neurone

Nerve cells transmitting the CNS instructions as electrical impulses

Dendrites

Carey impulse towards cell body

Axon

Carry impulses away from the cell body towards muscle

Neuromuscular junction

Where the motor neurone and muscle fibres meet

Synaptic cleft

ACh diffuses across the gap to stimulate contraction

All or none law

Sequence of impulses have to have sufficient intensity to stimulate all muscle fibres in a motor unit or none contract

Wave summation

Repeated nerve impulses with no time to relax causes a smooth sustained contraction

Tectanic contraction

Sustained muscle contraction caused by repeating stimuli

Spatial summation

The addition of impulses received at the same time but at a different location on the neuron (e.g bigger motor units), releases action potential after addition of impulses. In endurance motor unit rotation allows recovery

PNF

Advanced stretching technique which increases range of motion

Muscle spindles

Detect speed and how far a muscle is stretched and relays to the CNS which triggers stretch reflex

Golgi tendon organs

Detect isometric contraction and increased tension which send auto genie inhibition signals to relax muscles