plyometrics in rehabilitation
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Plyometrics in Rehabilitation. Rehabilitation Techniques for Sports Medicine and Athletic Training William E. Prentice. What is Plyometric Exercise. Specificity is an important parameter of an exercise training program Jumping movement is inherent in most sports - PowerPoint PPT PresentationTRANSCRIPT
PLYOMETRICS IN REHABILITATION
Rehabilitation Techniques for Sports Medicine and Athletic
TrainingWilliam E. Prentice
What is Plyometric Exercise
Specificity is an important parameter of an exercise training program
Jumping movement is inherent in most sports Running is a repeated series of jump-landing
cycles
Therefore, jump training should be used in the design and implementation of the overall training program and rehabilitation
What is Plyometric Exercise
Success in most activities is dependent upon the speed at which muscular force and power is generated.
Power combines strength and speed Can be increased by increasing the amount of
work or force that is produced and decreasing the amount of time required to produce force
Plyometrics is a form of training that attempts to combine speed of movement with strength
What is Plyometric Exercise
Plyometrics=quick, powerful movement involving pre-stretching of muscle and activating the stretch-shortening cycle to produce a subsequently stronger concentric contraction.
Takes advantage of stretch-shortening cycle (SSC) to increase muscular power
What is Plyometric Exercise
Main purpose of plyometric training is to heighten the excitability of the nervous system for improved reactive ability of the neuromuscular system
Plyometric Exercise Myotatic stretch reflex used to produce
powerful response of contracting muscles Upon landing muscles undergo a lengthening
eccentric contraction to decelerate movement and pre-stretch the muscles
Pre-stretch energy is then immediately released in an equal and opposite reaction Produces kinetic energy
Neuromuscular system must react quickly to produce concentric shortening contraction to produce upward change in direction
Plyometric Exercise Plyometric exercise should be used to
prepare athletes for return to activity Train specific movements in a biomechanically
accurate position Specific functional exercise used to emphasize
the rapid change of direction Can be used for upper and lower extremities Whether athlete is jumping or throwing the
musculature around the joint must first stretch and then contract to produce explosive movements
Biomechanical and Physiological Principles
Stretch-shortening cycle: Coupling of eccentric-concentric muscle contraction
Movement rarely begins from static position
Preceded by eccentric pre-stretch that loads muscle and prepares for concentric contraction
2 components work together to produce response:
Proprioceptive reflexesMechanical: Elastic properties of muscle fibers
Mechanical Characteristics of a Muscle
Three component model Contractile component (CC) Series Elastic Component (SEC) Parallel Elastic Component (PEC)
All interact to produce a force output
CC focal point of motor control, however SEC & PEC provide stability and integrity to fibers as muscle is lengthened
During lengthening energy is stored within the musculature in the form of kinetic energy
Mechanical Characteristics of a Muscle
When a stretch is applied , potential energy is stored That energy is applied as it returns to its
normal length when the stretch is released Analogy: stretching a rubber band
Significant increases in concentric muscle force production has been documented when immediately preceded by an eccentric contraction Uses the elastic energy stored during eccentric
contraction
Mechanical Characteristics of a Muscle
Ability to use stored elastic energy affected by 3 variables Time Magnitude of the stretch Velocity of the stretch
In order to increase concentric force production eccentric contraction must be of short range and performed quickly without delay
If large range, slow, with delay stored energy will be lost
Neurophysiological Mechanisms
Proprioceptive stretch reflex: Involve the mechanoreceptors in the muscle: Muscle spindle:
When muscle spindle is stretched sensory response sent to CNS and neurological impulses sent back to muscle causing motor response
Strength of muscle spindle response is determined by rate of stretch More rapidly load applied, greater firing frequency of the spindle and stronger muscle contraction
Neurophysiological Mechanisms
Golgi Tendon Organ:
Inhibitory effect by contributing a tension limiting reflex, restricting the amount of force that can be produced
Theorized that Plyometrics desensitizes GTO and allows more force to be produced
Neurophysiological Mechanisms Increased force production seen during SSC due
to combined effects of stored elastic energy and the Myotatic stretch reflex Increased amount of force production dependent upon
the time frame between eccentric and concentric contractions
Defined as Amortization Phase Electromechanical delay between eccentric and
concentric contractions Muscle must switch from overcoming work to
acceleration in opposite direction
Increased time in amortization phase will lead to decrease in force production
Neuromuscular Considerations Plyometric training can promote changes
within the neuromuscular system
Allow individual to have better control of contracting muscle and synergists
Can increase performance by enhancing nervous system to become more automatic
Program Development Should begin with establishing adequate
strength base
Allow body to withstand large stress placed on it (Safety)
Allow for greater force production
Increase in CSD of muscle will increase potential to store greater amounts of elastic energy
Plyometric Pre -requisites Biomechanical Examination
Functional movement screening Strength test
Poor strength and mechanics will result in loss of stability and increased stress absorbed in wt. bearing tissue Decrease performance and increase risk of injury
Stability Test Static and Dynamic Balance Test
Plyometric Pre -requisites Dynamic Movement Test
Single Leg Hop test-LE Seated chest pass or sit up and throw test -UE
Flexibility General and specific flexibility
High amount of stress applied to musculoskeletal system
Should do general and specific warm up before plyometric exercise
Plyometric Pre -requisites Classify individual as beginner, intermediate
or advanced Dependent on information found through
biomechanical, stability, and dynamic testing
Will determine where athlete begins plyometric program
Take into consideration tissue healing if post-injury
Take into consideration sport so Plyometric training can be specific to athletes position
SAID Principle!!!!!
Plyometric Program Development
Direction of Body Movement Weight of Patient Speed of Execution External Load Intensity Volume Frequency Training Age Recovery
Plyometric Program Development
Beginning of plyometric program emphasize technique and principles of Plyometrics For example, the importance of short
amortization phase Minimal time on ground, reverse the landing as
quickly as possible Focus on body, control, posture and mechanics As intensity increases, volume should decrease Plyometrics should be used in later phases of
rehabilitation. After appropriate strength base established and
athlete has performed closed chain exercises
Guidelines for Plyometric Programs
Sound, technical foundation Force reduction and force production should
be absorbed throughout entire body
Ankle, knee, hip, trunk, arms
Time and coordination of these body segments will yield positive ground reaction and high rate of force production
Guidelines for Plyometric Programs
Specific to individual goals of athlete Quality of work more important than
Quantity Greater intensity the greater recovery
time required Low to medium intensity if done at
conclusion of workout, high if done before When to fatigued to maintain proper
technique exercise should stop
Guidelines for Plyometric Programs
Progressive in nature
Only 2 to 3 times a week depending on periodization
Dynamic testing on regular basis to provide motivational feedback
Proper equipment: footwear, landing surface, external loads…Safety First!!
Plyometrics in Rehabilitation
Involve loading of the healing tissue Medial and Lateral Loading
Ability to accept weight on injured extremity and change direction
Imperative to return to sport with cutting maneuvers (Most Sports)
Rotational Loading Same as above
Shock Absorption (Deceleration Loading) Eccentric load of muscle and tendon Increase in tensile strength
Specific Plyometric Exercises
Double extremity to Single Extremity Vertical Hops to Lateral Hops to Diagonal
Hops Flat surface to box jumps Non weighted to weighted Jumps to Hops to Bounding
Manipulate Volume, frequency, and intensity to advance program appropriately
Re-evaluate and re-assess athlete to prevent injury and provide motivational feedback