LEWIS: PNF stretching Flashcards Preview

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Flashcards in LEWIS: PNF stretching Deck (28):
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PNF=

Proprioceptive neuromuscular facilitation

1

PNF used alternating contraction and relaxation movements for

Flexibility

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PNF techniques can be both

Passive (no associated muscular contraction)

Active (voluntary muscle contraction)

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PNF facilitate or help the body's muscular

Inhibition

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Most practical style of PNF is the

CRAC technique

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CRAC =

Contract
Relax
Antagonist
Contract

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CRAC uses isometric muscle contractions as it's

Basis

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Isometric muscle contractions completed immediately before a passive stretch help to achieve

Autogenic inhibition - muscles gradually relax

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Muscle spindles sense how fast a muscle is being stretched and, when activated, produce the

Stretch reflex

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Muscle spindles are highly specialised receptors located within muscle cells, which protect the muscle from

Injury (overstretching and tearing)

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Stretch reflex causes the muscle to

Contract and prevents overstretching of the joint

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Also located within the muscles tendon is another sensor called the

Golgi tendon organ (GTO)

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GTO senses how much tension is being placed on the

Tendon

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Autogenic inhibition is reflex relaxation that occurs in the same muscle where the

GTO is stimulated

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GTO differs from the muscle spindle in that when activated it

Relaxes the muscle, so that the stretch being applied does not cause tearing or overactivity of the nerve fibres

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Often isometric referred to as 'hold' and concentric referred to as

'Contract'

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PNF is

Best performed with a partner - make sure they are attentive and focused on the performer so as not to cause overstretching

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General guidelines for PNF (5) =

-Avoid PNF immediately before, or in the morning of, a competition and leave 48h between PNF stretching routines

-Perform only one exercise per muscle group in a session - attempt 2-5 sets

-Each set should consist of 1 stretch held up to 30s after the contracting phase

-Not recommend for under 18s

-If PNF is to be performed as a separate exercise session, a thorough warm-up must precede it

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when the isometric contraction is relaxed, the stretched fibres retain their ability to stretch beyond their limit, the whole muscle is able to stretch beyond its initial maximum and you get:

increased flexibility

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GTOs are activated when a muscle is stretched or contracted isometrically. They inhibit the development of too much tension in a muscle, allowing the muscle to relax and lengthen. This lengthening during a stretch also helps prevent the tendon or muscle tearing. This process is known as:

autogenic inhibition

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When an agonist muscle contracts concentrically, the antagonist muscle in turn relaxes, allowing the agonist muscle to move a limb through its full range of motion without interference from tension in the antagonist. This is called:

reciprocal inhibition

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PNF stretching is mainly concerned with:

reciprocal inhibition

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First part of a PNF stretch is an initial passive stretch is made to get the joint into a

held, stretched position

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(2) stretched agonist is isometrically contracted for:

6-10s

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(3) the muscle is relaxed and its antagonist immediately performs an isometric contraction that is again held for:

6-10s

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(4) The muscles are relaxed for 20s before performing another:

PNF stretch

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As the agonist muscle contracts isometrically, the GTOs are activated, autogenic inhibition occurs, and the antagonist relaxes. When the antagonist of the limb being stretched contracts, the agonist muscle relaxes through:

reciprocal inhibition

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These relaxed agonist muscles can be stretched further through repeated cycles of CRAC, increasing flexibility and range of motion. This is helped by the fact that the muscle spindles are:

disengaged