Plyometrics involve exercises with a rapid eccentric muscle contraction followed immediately by a concentric contraction, utilizing the stored elastic energy. Key phases include the eccentric loading phase, transition coupling phase, and concentric take-off phase. Plyometrics can improve muscle strength, power, and injury prevention when performed properly, progressively over time, and under supervision. Precautions must be taken regarding surface, age, injury history, and ensuring adequate warm-up, recovery time, and progression of intensity.
2. DEFINITION
• Plyometrics exercise involves a stretch of the muscle-tendon unit immediately
followed by a shortening of the muscle unit.
3. PHYSIOLOGY OF PLYOMETRIC EXERCISES:-
• Two importantphysiologicalfactors are:-
a)The serial elasticcomponents of muscle, which includethe tendons and the
cross bridging characteristicsof the actin and myosin that make up the muscle
fibres;and
b)The sensors in the muscle spindles(proprioceptors)that play the role of
presentingmuscle tension and relayingsensory input related to rapid muscle
stretching for activation of stretch-reflex.
4. PHASES OF PLYOMETRIC EXERCISES:-
i) Eccentric phase or loading phase:-
➢ This initial phase involves rapidmuscle lengthening.
➢ It involves the preloading of the agonist muscle group.
ii) Transition phase or coupling phase:-
➢ It is the transitionbetweenthe loading phase(negativework) andunloading phase (positive work) of a plyometric exercise.
➢ It is a definitive phase that ultimately determines the synergistic effects gainedby stretch-shortening cycle(SSC).
➢ This phase needs tobe as short as possible otherwisethe energy storedduring the eccentric phase dissipates, reducing plyometric
effect.
iii) Concentric phase or take-off phase or unloading phase:-
➢ It occurs immediately after the coupling phase andinvolves shortening of muscle tendon.
➢ It uses storedenergy toincrease force of movement.
5. BENEFITS:-
i) It helps in injury prevention.
ii) It helps in enhancing sports performance.
iii) It is an effectivemethodto improve muscle strength and power.
iv) It is beneficial for individuals with moderately lowas well as high fitness levels prior to the
start of training.
v) When used as a programof rehabilitation,special care must be taken to ensure the patient’s
readiness for such activity.
7. PRECAUTIONS:-
i) If high-stress, shock-absorbing activities are not permissible do not incorporate plyometric
training.
ii) If a decision is made to include plyometric activities in rehabilitation program for children or
elderly patients, select only beginning level stretch shortening drills against light resistance.
iii) Wear shoes that provide support for lower extremity plyometrics.
iv) Always warm-up prior to plyometric training with a series of active, dynamic trunk and extremity
exercises.
v) During jumping activities, emphasize learning techniques for a safe landing before progressing to
rebounding.
vi) Progress repetition of exercise before increasing the level of resistance used or the height or
length of jump.
vii) Allow adequate time for recovery with 48hrs to 72hrs between sessions of plyometric exercise.
viii)Stop an exercise if a patient can no longer perform the plyometric activity with good form.
8. SAFETY CONCERNS:-
i) Landing surface-wrestling mat type idle
ii) Age- young athletes with open growthplates should avoidhigh intensity jumps, depth jumps
etc
iii) Maturity- athlete able to followdirections or not?
iv) Size-those over 220lbs have high injury risk.
v) Prior injury, jointlaxity, spinal dysfunction may affect one’s ability to do plyometrics.
vi) Plyometricsmust be supervisedby knowledgeable instructor.
vii)Boxes should have non-slip surfaces.
viii)Proper footwear for athlete.
9. PLYOMETRIC ACTIVITIES FOR UPPER EXTREMITIES:-
i) Catching and throwing a weightedball with a partner or against a wall, bilaterally then
unilaterally
ii) Stretch-shortening drills with elastictubing using anatomical and diagonal motions.
iii) Swinging a weightedobject
iv) Dribbling a ball on the floor or against the wall
v) Push-offs froma wall or countertopwhile standing.
vi) Drop push-ups froma lowplatformto the floor and back to platform.
vii)Clap push-ups
10. PLYOMETRIC ACTIVITIES FOR LOWER EXTREMITIES:-
i) Repetitive jumping on floor;in place, forwardor back, side to side, zigzag,jump with
rotations etc
ii) Vertical jumps and reaches and proper landing
iii) Multiple jumps across a floor
iv) Box jumps: initially off and breeze,then off and back on box, increasing speed and height.
v) Side to side jumps(box to floor to box)
vi) Jumping over objects in floor
vii)Hopping activities: in place, across a surface, over objects on the floor
viii)Depth jump
11. PRINCIPLES OF PLYOMETRICS:-
a) Preparation for plyometrics:
➢ Prior to start of plyometrics, a patient should have an adequate base of muscle strength and
endurance, as well as flexibility.
➢ An 80%-85% level of strength and 90%-95% pain free ROM of moving joint must be available.
➢ Sufficient strength and stability of proximal regions of body for balance and postural control are
necessary prerequisites.
b) Specificity of training:
➢ A plyometric exercise should be designed with specific functional activities in mind and should
include movement patterns that replicate the desired activity.
c) Progression and parameters:
➢ Exercises should be sequenced from easy to difficult and progressed gradually.
➢ Programs also should be individually designed to meet each patient’s needs and goals.
➢ Prior to initiating plyometric exercises , series of warm-up exercises must be performed to reduce
risk of injury to the contracting muscle group
12. PARAMETERS TO BE CONSIDERED:-
i) Speedof drills:
➢ Drills shouldbe performedrapidly but safely
➢ Rate of stretchof contractionis more important thanthe lengthof stretch.
➢ Emphasis should be placedon decreasing the reversal time whentransitioning fromaneccentric toaconcentric contraction.
ii) Intensity:
➢ Resistance shouldbe increasedgradually soas tonot slowdown the activity.
➢ Methods of increasing external resistanceinclude using aweight belt, heavier weightedballs etc
•
iii) Repetitions , frequency, andduration:
➢ The number of repetitions shouldbe increasedas long as proper formor technique is maintained.
➢ The number of exercises is alsogradually increasedinasingle session.
➢ The optimal frequency of plyometric sessionsis twosessionsper week, whichallows a48-72 hr recovery periodbetweensession…