Plyometrics Objective To improve speed power elastic strength Athletes involved Sprinters games players basketball Typical exercises Jumping bounding medicine ball work Basic theory ID: 272353
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Slide1
Plyometrics and PNF TrainingSlide2
Plyometrics
Objective:
To improve speed, power, elastic strength
Athletes involved:
Sprinters, games players (basketball)
Typical exercises:
Jumping, bounding, medicine ball workSlide3
Basic theory
First an
eccentric contraction
takes place
E.g. breaking action of the quadriceps when landing, slows down the movement, lengthening of muscle.
Followed by a
concentric contraction
The muscle shortening on the upward phaseSlide4
Example
1.
Tricep
lengthens as landing happens (eccentric contraction)
2. Upward phase of movement –
tricep
shortening (concentric contraction)Slide5
Three phases of plyometrics
The
eccentric phase
, or landing phase, where the agonist muscles are contracting eccentrically to control movement (
elatsic
energy is stored)
The
amortisation phase
, or transition phase, which is the time between eccentric and concentric contractions (shorter the more explosive the movement)
The
concentric phase
, which is the jumping phase, when the agonist muscles contract concentricallySlide6
Use the example below to demonstrate your understanding of plyometricsSlide7
Use the example below to demonstrate your understanding of plyometrics
1.
Quadricep
lengthens as landing happens (eccentric contraction)
2. Upward phase of movement – quads shortening (concentric contraction)Slide8
Adaptations
Training using plyometrics leads to:
Increased contractility of the fibre
Increased elasticity – muscle contracts with more power (ELASTIC STRENGTH)Slide9
How does this work?
Around the myofibrils there are
muscle spindles (
propriorecptors
)
.
The muscle spindle’s job is to relay information to the brain on the condition of the muscle.
As the muscle rapidly lengthens( contracts) the spindles send message to
CNS
Message sent to increase the concentric contraction
To prevent muscle from being over lengthened, over stretched and therefore injured.
CALLED
STRETCH REFLEX
This causes increase in the elasticity and contraction force.
ELASTIC ENERGY IS STORED.Slide10
PNF Training
Proprioreceptive
Neuromuscular Facilitation
Objective
To improve flexibility
Athletes involved:
Elite performers
Typical exercises:
Hamstring stretch, pectoral stretchSlide11
Example – hamstring stretch
Passive stretch due to helper.
The helper produces force by pushing on the foot.
Causing a stretch in the hamstring, lengthening
As the muscle lengthens the muscle spindles work causing stretch reflex. Slide12
Example – hamstring stretch
Passive stretch
Performer applies force back,
isometric contraction (stays same length) in
the agonist
, helper prevents movement. Hold for about 8 seconds.
Relax
Leg stretched AGAIN (another isometric contraction) causing leg to stretch in a greater range of movement. Due to muscle spindles delaying sending message to CNS which switches off stretch reflex.Slide13
Use the example below to demonstrate your understanding of PNF.Slide14
Use the example below to demonstrate your understanding of PNF.
Passive stretch
Performer applies force back, isometric contraction (stays same length), helper prevents movement. Hold for about 8 seconds.
Pectorals stretched AGAIN (another isometric contraction) causing arms to stretch in a greater range of movement. Due to muscle spindles delaying sending message to CNS which switches off stretch reflex.Slide15
Adaptations
Training using PNF leads to:
Muscle AND connective tissue (tendons and ligaments) become more flexible (move through a greater range of movement).
The most common PNF technique is the CRAC Technique: contract – relax
, antagonist
- contractSlide16
Theory
PNF stretching also triggers the GOLGI TENDON ORGAN which is encased in the tendon
Job is to prevent overstretching
If the muscle is under too much pressure during
isometrical
contraction, the GTO relaxes the muscle to avoid tearing.
GTO override the stretch reflex allowing the relaxation to be extended.
The athlete practices engaging the GTO during exercise and then follows with a deep stretch pushing the muscle beyond its normal range.