Lecture 5 - Plyometrics (PHT 245) Flashcards
What is plyometrics?
Is a type of exercise that uses explosive movements to develop a muscular power and to generate a large amount of force quickly. That involves the activation of stretch shortening cycle.
What is the Phases of plyometrics ( stretch - shortening cycle) are?
- eccentric phase (loading)
- amortization phase (Transition)
- Concentric phase (unloading)
What is the eccentric phase?
-Is when there is lengthening of the muscle taking place.
-there is a increase in muscle spindle activity.
-Once the muscle spindle is activated you will have a subsequent contraction of the muscle that is lengthening.
-The lengthening muscle then stores energy (potential energy)
-which is released during the unloading phase.
What is the amortization phase?
-this phase should be relatively short.
-If not the stored potential energy from the loading phase will be lost
-Which will result in a less forceful contraction
What is the concentric phase?
-you have a concentric contraction which takes place.
-this concentric contraction releases the stored potential energy during this phase.
Two types of models for plyometrics?
- Mechanical Model of plyometrics
- Neurophysiological model of plyometrics
What is the mechanical model of plyometrics about?
-Is about the increased power production by the muscle during the stretch-shortening cycles.
-Relates to the storage of potential energy following a rapid stretch of the muscle
- This model incorporates the (SEC) series elastic component, which is found in detaintant and is responsible for storing elastic energy and the parallel elastic component which provide resistance when a muscle is being stretched.
-if the muscle immediately contracts the stored energy is released.
What is the neurophysiological model of plyometrics about
-Concentric muscle force is increased with the use of the stretch reflex
-The reflexive activity increases the force the muscle produces
-As with the mechanical model if the muscle action does not immediately follow a stretch the potential effect of the reflex is negated
when to use plyometrics?
-In sporting environments
-rehab programmes
-general population (policeman)
what are the precautions that should take place?
-Time (the duration you engaging in should not be prolonged)
-DOMS (degree of delayed onset of muscle soreness)
Contraindications:
-are acute conditions or factors that might predispose them to a worsening conditions.
-acute inflammatory condition
-post - operative conditions
-instability (further place the patient in a worse condition)
Contra-indicated populations are?
-Age (patients that are very young or very old) (young patients are still growing, while older patients have lower bone density)
-Experience (more experience=less pain/ less experience = more pain)
-current training level
The plyometrics programme design:
-Age (not too young or too old)
-Training experience and current training level (whether they have sufficient strength or control when doing these exercises)
-Injury history (might cause reinjury) (objective tests)
-Physical testing results
-Training goals (the sport or occupation they involved in)
-Incidence of injury in a client’s job or chosen activity (do they get injured often)
Programme design
Consider age, body weight, competitive level, surface, footwear, proper technique, progression, & goals when developing a program
-Direction of Body Movement
Horizontal body movement is less stressful than vertical movement
Dependent upon weight of athlete & technical proficiency demonstrated during jumps
-Weight of Athlete
The heavier the athlete, the greater the training demand placed on the athlete
-Speed of Execution of Exercise
↑ speed of execution on exercises (SL hops, alternate-leg bounding) raises the training demand on the individual
-External Load –ankle weights
Adding an external load can significantly ↑ the training demand
Do not raise the load to a level that will significantly slow the speed of movement
-Intensity (how much effort)
Amount of effort exerted
Can be controlled by type of exercise performed (DL jumping – less stressful than SL jumping)
Progress from simple to complex activities
Adding external weight or raising box height increases intensity
-Volume (reps and sets of exercise)
Amount of work performed during one session
Total # of foot contacts in one session
Beginners –
Advanced –
-Frequency (how often/48-72hrs)
Optimum frequency is suggested that 48-72 hours of rest are necessary for full recovery
-Training Age
Younger ages – overall training demand should be kept low
Youth sports involve plyometric movements
Research has shown that plyometric training in youth does result in strength gains & increases bone mineral content in females
-Recovery
Rest time between exercise sets
Longer recovery period should be used to allow restoration of metabolic stores because plyometrics is anaerobic in nature
Power training – work rest ratio 1:3 or 1:4
Endurance training – 1:1 or 1:2 ratio
Without recovery there is no improved performance
