1. Plyometric Training

2. Plyometric Training
What type of exercise is plyometric training – can you give examples?
Which component of fitness does plyometrics improve?
Describe what happens to the muscle in an eccentric contraction.
Describe what happens to the muscle during a concentric muscle contraction.

3. What does it involve?
A type of exercise using explosive movements to develop muscular power,
E.g. bounding, hopping, and jumping
Usually organised in a circuit
Involves an eccentric contraction, followed immediately by a concentric contraction
The eccentric muscle contraction loads the muscle by storing elastic energy
Which, when released produces a forceful and rapid contraction.

4. Role of Muscle Spindles
These protect the muscle from injury
They detect how far and fast a muscle is being stretched (eccentric phase)
The muscle spindles produce the “stretch reflex” which causes the muscle to contract to prevent it from being overstretched
Messages are sent from the spindles to the CNS which then stimulates the contraction of the muscle (concentric phase)
The force of the reflex is determined by the speed of the stretch e.g. faster stretch, more powerful the contraction (reflex)
The elasticity of muscle membrane can be developed through plyometric training, therefore future contractions will be more powerful.

5. Advantages of Plyometrics Disadvantages of Plyometrics
Specific movement patterns can be replicated from sport
Varied training programme
Improvements in power
Increased risk of injury
Greater recovery period is required between sessions

6. Proprioceptive Neuromuscular Facilitation

7. Proprioceptive Neuromuscular Facilitation (PNF)
Advanced stretching technique
Develops flexibility/mobility

8. Role of Muscle Spindles
Golgi Tendon Organs (GTOs) – located in muscle tendons to assess tension placed on tendons
When activated it causes the muscle to relax (opposite to muscle spindles),
This allows the muscle to stretch further.

9. Procedure for PNF
Passive stretch – enables muscle to extend beyond normal limits
Isometric contraction – at the optimal point of the stretch the athlete attempts a forceful contraction of the stretched muscle
Conscious relaxation –the performer relaxes the muscle
Passive Stretch – the range of motion can now be extended

10. Theory Behind PNF
During the passive stretch the muscle spindles are activated (contraction) and don’t allow a further stretch,
The stretch activated by the muscle spindle initiates the isometric contraction,
The isometric contraction then activates the golgi tendons (tension in the tendons is detected)
This over rides the stretch reflex (muscle spindle action)
The muscle relaxes (action of the golgi tendons)
The muscle can now be stretched further.

11. Task Design a plyometrics circuit for either:
An advanced basketball player
An intermediate hurdler
A beginner volleyball player
Design a PNF circuit for :
An advanced gymnast
An intermediate javelin thrower
A beginner swimmer