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Physical Education -Muscle fibre recruitment: muscular contraction
Muscular contraction
How muscles are stimulated
The nerve that goes to the muscle is called a MOTOR NEURON [1]. Motor
neurons are responsible for stimulating a number of muscle fibres -
together they are called a MOTOR UNIT.
When precise movement is required, 1 motor unit may stimulate only 1-2
fibres, e.g. movement of the eye.
When gross movement is required, 1 motor neuron [2] may stimulate 80-100
fibres, e.g. quadriceps muscle.
When an electrical impulse reaches a threshold, all muscle fibres of that
unit contract maximally. It is not possible for a muscle fibre to contract
partially - it's all or nothing.
The intensity of muscular contraction is governed by the number of motor
units recruited. The stronger the impulse, the more motor units (nerve cell
and muscle fibres) are activated. The greater the frequency of arrival of
impulses, the greater the force developed by that muscle. This is how we
are able to lift a glass one minute and a dumbbell the next.
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[2] http://alison.com/#
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1 motor neuron may stimulate 80 - 100 fibres or stimulate 1 - 2 fibres for specific movement.
muscle usually works across a joint. it is attached to both the bones by strong cords called tendons,when the muscle contracts,usually just one bone moves
What is muscular contraction muscle fibre recruitment?
Muscular contraction:- Muscle fibre recruitment. The nerve that goes to the muscle is called a MOTOR NEURON. Motor neurons are responsible for stimulating a number of muscle fibres - together they are called a MOTOR UNIT. When precise movement is required, 1 motor unit may stimulate only 1-2 fibres, e.g. movement of the eye. When gross movement is required, 1 motor neuron may stimulate 80-100 fibres, e.g. quadriceps muscle. The all or nothing principle of muscle contraction When an electrical impulse reaches a threshold, all muscle fibres of that unit contract maximally. It is not possible for a muscle fibre to contract partially - it's all or nothing.
What is the contraction of muscles?