1.3 PE-Sport Physiology - The neuromuscular system

What are the three muscle fibre types and their general uses?

What are the three muscle fibre types and their general uses?

• Type 1(slow oxidative)-Used for low intensity endurance exercise

• Type IIA (fast oxidative glycolytic)-Used for high intensity middle distance events like 1500m run

• Type IIX (fast glycolytic)-Used for short duration with high intensity like powerlifting

Name the functional characteristics of Type I muscle fibres

• Slow contraction speed

• low force produced

• Low fatiguability

• very high aerobic capacity

• Low anaerobic capacity

• Slow motor neurone conduction capacity

Name the structural characteristics of type I muscle fibres

• Small motor neurone size

• High mitochondrial density

• High myoglobin content

• High capillary density

• Low Myosin ATPase activity

Name the functional characteristics of Type IIa muscle fibres

• fast contraction speed

• High force produced

• medium fatiguability

• medium aerobic capacity

• High anaerobic capacity

• fast motor neurone conduction capacity

Name the structural characteristics of type IIa muscle fibres

• Large motor neurone size

• medium mitochondrial density

• medium myoglobin content

• medium capillary density

• High Myosin ATPase activity

Name the functional characteristics of Type IIx muscle fibres

• fast contraction speed

• High force produced

• High fatiguability

• Low aerobic capacity

• Very High anaerobic capacity

• fast motor neurone conduction capacity

Name the structural characteristics of type IIx muscle fibres

• Large motor neurone size

• low mitochondrial density

• low myoglobin content

• low capillary density

• High Myosin ATPase activity

What does a motor unit consist of

Motor neurone and its muscle fibres

What is the all or none law?

where a sequence of impulses has to be sufficient intensity to stimulate all of the muscle fibres in the motor unit or non of them will contract

What is wave summation?

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

What is a tetanic contraction?

A sustained muscle contraction caused by a series of fast repeating stimuli

What is spatial summation

When the strength of a contraction changes by altering the number and size of the muscles motor units

What is proprioceptive neuromuscular facilitation (PNF)?

An advanced technique of stretching, which is considered to be one of the most effective methods for improving flexibility and range of movements

What are muscles spindles?

These detect how far and how fast a muscle is being stretched and produce the stretch reflex

Explain why we have a stretch reflex

This reflex action which causes the muscle to contract to prevent over-stretching reduces the risk of injury

What are Golgi tendon organs?

These are activated when there is tension in a muscle