The Neuromuscular System

• All or none law


  Impulses arriving at the neuron must reach a threshold level. If they do all of the muscles in that motor unit will contract. If they do none will contract. A motor unit cannot partially contract
• Fast glycolytic (type IIx)


  These muscle fibres produce the highest force and speed of contraction, via the anaerobic respiration. They are highly susceptible to fatigue
• Fast oxidative glycolytic (type IIa)


  These muscle fibres produce a high force and speed of contraction, primarily via the anaerobic respiration. However, a limited degree of aerobic capacity allows some fatigue resistance
• Golgi tendon organ

  Proprioceptors which are activated when there are high levels of tension in a muscle
• Golgi tendon organ

  • They can initiate autogenic inhibition, which is a sudden relaxation of a muscle. This can override the stretch reflex in PNF stretching
• Motor units


  A motor neuron and its muscle fibres
• Muscle spindles

  Proprioceptors which detect how far or fast a muscle is stretching
• Muscle spindles


  • They initiate the stretch reflex, where a muscle will contract, to prevent over stretching
• PNF (proprioceptive neuromuscular facilitation)


  An advanced stretching technique. Considered to be one of the most effective methods for increasing range of motion at a joint
• Slow twitch (type I)


  These muscle fibres produce a low force and speed of contraction, via aerobic respiration. However, they are highly fatigue resistant, allowing them to continuing working for long period of time
• Spatial summation

  The addition of impulses received at the same time, but at different location on the neuron. If, when added together, the impulses are large enough an action potential will be released
• Tetanic contraction


  A smooth sustained muscle contraction. Not a muscle twitch
• Wave summation


  Repeated nerve impulse which does not allow the muscle fibres time to fully relax. This results in a tetanic contraction