Plyometrics:
Reactive/Power
Training
Reactive Training
• Reactive training:
– A quick powerful movement involving an
eccentric contraction, followed immediately
by an explosive concentric contraction
– This is accomplished through plyometric
exercises
• Plyometrics are activities that enable a
muscle to reach maximal force in the
shortest amount of time possible. This is
called the rate of force production
Plyometrics
 This type of training involves powerful
muscular contractions in response to a
rapid stretching of the involved
musculature.
 These powerful contractions are not a
pure muscular event; they have an
extremely high degree of central nervous
system involvement.
 Reactive training improves neuromuscular
efficiency
Plyometrics
• Plyometric exercises can be
incorporated once a client has
achieved proper core and balance
stabilization
• Ultimate goal of plyometrics is to
increase the reaction time of:
Plyometrics
 A good example of this is watching any
basketball player jump.
 They jump higher when they can take a few
steps before the jump.
 The reason for this is that the few steps create
momentum.
 This momentum is used to create a bigger and
faster “load” on the leg plant prior to jumping.
 The response to this greater load is a greater
contraction by the legs and a higher jump height.
 The same phenomenon exists with all explosive
actions.
Mechanical Model of Plyometric Exercise
• Elastic energy is stored following a rapid
stretch, then released during a concentric
muscle action increasing total force production
• The mechanical model presents the function of
the musculotendionous unit as a relationship
between three mechanical components
Mechanical Model of the Muscle
• Three elements compose the
mechanical model of the muscle
influencing its mechanical behavior
and effecting contraction:
Contractile Component
• The contractile
component
represents the
muscle fibers,
which are the
active part of the
muscle and are
competent to
produce tension
Parallel Elastic Component
• The parallel
elastic component
represents the
connective tissue
surrounding each
muscle fiber,
groups of fibers
and the whole of
the muscle.
Series Elastic Component
• The series elastic element refers mainly to the
tendons of the muscle which are placed "in
series" with the contractile and parallel elastic
elements.
• When the muscle-tendon unit is stretched
during an eccentric contraction, the SEC acts
as a spring and is lengthened, storing elastic
energy
• If the muscle immediately begins a concentric
contraction, the stored energy is released
Neurophysiological Model of Plyometric
Exercise
• This model represents the
• Plyometric exercise is composed primarily
of
• Muscle spindles are sensitive to the rate
and magnitude of a
; when a quick
stretch is detected muscle activity
increases
Neurophysiological Model of
Plyometric Exercise
• Stretch Reflex:
– The body’s involuntary response to an
external stimulus that stretches the muscles
• When muscle spindles are stimulated, the
stretch reflex is stimulated, sending input to
the spinal cord via nerve fibers
• The nerve impulses travel to the agonist
muscle fibers, causing a reflexive muscle
action
Stretch Shortening Cycle (SSC)
• The stretch-shortening cycle (SSC)
employs both the energy storage of the
SEC and stimulation of the stretch reflex
to facilitate maximal increase in muscle
recruitment over a minimal amount of time
• A fast rate of musculotendinous stretch is
vital to muscle recruitment and activity
resulting from the SSC
Stretch-Shortening Cycle
• The SSC Model involves
three phases:
Phase I: Eccentric Phase
• Stretch of the agonist muscle
• Preloading the agonist muscle group
• The SEC (muscle-tendon unit) stores elastic
energy
• Muscle spindles are stimulated
• Signal is sent to the spinal cord
• Example: A basketball jump shot
• The person performs a half-squat before
jumping up
• The time from the beginning of the squat to the
bottom of the movement is the eccentric phase
Phase II: Amortization
• Amortization or Transition Phase is the time between
the eccentric and concentric phases
• Pause between Eccentric to Concentric muscle
actions
• Spinal Cord begins to transmit signals to the agoniststretched-muscle group
• If the amortization phase lasts too long, the energy
stored during the eccentric phase will be dissipated
as heat
• Example: Basketball jump shot
• From the downward half-squat as soon as upward
movement begins, amortization phase has ended
Phase III: Concentric Phase
• Shortening of agonist muscle fibers
• Elastic energy is released from the
SEC to increase force production
• The stretched muscle is stimulated
neurally
• Example: Following the half-squat in
the jump shot, the individual moves
upward
Explain the SSC with a Basketball
Jump Shot
Phase I:
Phase II:
Phase III:
Stretch Shortening Cycle
Basketball Jump Shot
• Phase I: Eccentric Phase
The agonist muscles (quadriceps)
undergo a rapid stretch
• Phase II: Amortization
Phase
There is a delay in the movement
• Phase III: Concentric Phase
The quadriceps acts
concentrically to extend the knee,
allowing the person to push off
the ground
Plyometric Program Design
• Ideal when the goal is to improve
muscular power
• Power: The time rate of doing work
– Force x distance/time
– Force x velocity
• Examples: police officers having to run
quickly and change direction or jump
over obstacles, firefighters, warehouse
workers lifting boxes…
Plyometric Program Design
• Exercise Selection:
– Safe
– Done with supportive shoes
– Performed on a proper training surface
• Performed with proper supervision
• Progressive:
– Simple to complex
– Known to unknown
– Stable to unstable
– Body weight to loaded
– Activity specific
Plyometric Program Design
• Variables:
– Plane of motion
– Type of resistance
• MB
– Type of implements
• Boxes
• Cones
• Hurdles
– Muscle action (eccentric, isometric,
concentric)
– Speed of motion
– Duration
– Frequency
Plyometric Program Design
• Be systematic
• Be progressive
• A client must exhibit proper levels
of core strength and balance
before progressing into reactive
training
Age Considerations
• Adolescents
– Consider both physical and emotional
maturity.
– The primary goal is to develop
neuromuscular control and anaerobic skills
that will carry over into adult athletic
participation.
– Gradually progress from simple to complex
– The recovery time between workouts should
be a minimum of two to three days.
Age Considerations
• Older Adults:
– Can perform plyometric exercises as long as
modifications are made for orthopedic
conditions and joint degeneration
– The plyometric program should include no
more than five low- to moderate-intensity
exercises
– The volume should be lower, that is, should
include fewer total foot contacts than a
standard plyometric training program
– The recovery time between plyometric
workouts should be three to four days
Contraindicated Populations
• Plyometric training may alter
bone structure; spine height
has been shown to decrease
by up to 2 mm following a
depth jumping program (high
intensity)
• Research has yet to determine
the age at which one can
participate in a plyometric
training program
Contraindicated Populations
• Adolescents should be careful
because of epiphyseal plate closures
• Older adults should be careful
because of osteoporosis
• Clients who never participated in
resistance training should be
precluded
• Plyometric training requires strength
and muscle control
Needs Analysis
• Analyze needs of the client:
1. Age (safest over the age of 13)
2. Training experience and current level of training
(more than three months of resistance training)
3. Injury history (no current injuries)
4. Fitness Evaluation: what are the client’s current
abilities (beginner, intermediate, advanced)?
5. Training Goals: does the client want to improve
a skill or a particular move (volley ball spike,
tennis serve, baseball pitch…) or on the job
activity
Mode (Type)
• Determined by the general body
parts that are performing the given
exercise
• Example:
–Depth Jump is a lower body
plyometric exercise
–MB Chest Pass is an upper body
plyometric exercise
Lower Body Plyometrics
• Jumps-In-Place:
– Squat jump and tuck jump
• Standing Jumps:
– Vertical jump and jumping over barriers
•
•
•
•
Multiple hops and jumps
Bounding and skipping
Box Jumps
Depth Jumps
Squat Jump
1. Stand with feet shoulder-width apart
2. Draw naval in and activate gluteals
3. Jump up, extending arms overhead
4. Land softly, maintaining optimal alignment
and repeat immediately
Tuck Jumps
•
•
•
•
Stand with feet shoulder-width apart
Draw naval in and activate gluteals
Jump up, bringing knees to chest
Land softly, maintaining optimal alignment
Box Jumps
• Stand in front of a box or platform with feet
shoulder-width apart
• Draw in navel and activate gluteals
• Using arms, jump up and land on top of
box, keeping toes pointing straight ahead
and knees over toes
• Step off box
Bounds
• Jog into the start of the drill for forward
momentum.
• After a few feet, forcefully push off with the left
foot and bring the leg forward. At same time
drive your right arm forward.
• Repeat with other leg and arm
• This exercise is an exaggerated running motion
focusing on foot push-off and air time
Depth Jumps
• Stand on a box or platform with feet shoulderwidth apart
• Draw in naval and activate gluteals
• Using arms, jump off the box and land on floor,
keeping toes pointing straight ahead and knees
over toes
Upper Body Plyometrics
• Not used as often
–MB Chest Pass
–MB Slam
–Two-Hand Overhead Throw
–Single-Arm Throw
–Depth Push-Up
–Push-Up with a Clap
–Power Drop
Overhead Throw and Side Throw
Overhead Back Toss
• Stand with feet slightly wider than hip-width apart.
• Have a partner or trainer stand approximately 10-15
yards behind you.
• Grasp MB and lower body into a squat position.
• Explode up extending the entire body and throwing
medicine ball up and over the body.
• The goal is to throw the ball behind you as far as you
and generating most of the power in the legs.
MB Slams
• Stand with feet parallel, shoulder-width apart
• Pull MB back behind head and forcefully throw
ball down on the ground as hard as possible.
• Catch the ball on the bounce from the ground
and repeat according to prescribed repetitions
Plyometric Push-Up
• Get into a push-up position.
• Lower yourself to the ground and then
explosively push up so that your hands leave
the ground.
• Catch your fall with your hands and immediately
lower yourself into a push-up again and repeat
Intensity
• Plyometric Intensity refers to the amount of
stress placed on muscles, connective tissues,
and joints
• Factors affecting Intensity include:
–
: progress from double to single
leg support places more stress on muscles,
connective tissues, and joints
–
: greater speed increases intensity
–
: Raise the body’s center of gravity
by increasing the height of the drill
: Greater the individual’s weight
more stress is placed on body. External
weight can be added (vests)
Intensity
• Low Intensity:
–Squat jump and vertical jump
• Moderate Intensity:
–Double leg tuck jump and split squat
jump
• High Intensity:
–Depth jump and pike jump
Frequency
• Number of plyometric sessions
per week
•
plyometric sessions
per week
Volume
• Number of reps and sets
performed during training sessions
• Lower Body Plyometrics Volume:
–Number of foot contacts per
workout or expressed as distance
• Upper Body Plyometrics Volume:
–Number of throws or catches
Lower Body Plyometrics Volume
Guidelines
Recovery
• Recovery between sessions:
– 48-72 hours between sessions
• Recovery for depth jumps may consist of 5-10
seconds of rest between reps and 2-3 minutes
between sets
• Work to rest ration is 1:5 to 1:10 specific to the
plyometric activity
• Drills should not be thought of as
cardiorespiratory conditioning exercises but as
power training
• Furthermore, drills for a given body area should
not be performed two days in succession.
Plyometric Length and Progression
• Program Length
– Currently, most programs range from 6 to 10
weeks; however, vertical jump height
improves as quickly as four weeks after the
start of a plyometric training program
• Progression
– Plyometrics is a form of resistance training
and thus must follow the principles of
progressive overload (the systematic
increase in training frequency, volume, and
intensity in various combinations).
Warm-Up
• Plyometric
exercise
sessions must
begin with a
general warm-up,
stretching, and a
specific warm-up
• Specific warm-up
should consist of
low intensity
dynamic
movements
•
•
•
•
•
Plyometrics, Aerobic Exercise and Resistance
Training
Can combine upper body RT with lower body
plyometrics and vice versa
Performing heavy RT and plyometrics in the
same day is not recommended
Aerobic exercise may have a negative effect on
power production
Perform plyometric exercise before aerobic
endurance training
Some advanced athletes may benefit from
complex training, which combines intense
resistance training with plyometric exercises
Safety Considerations
• Pretraining Evaluation of the Athlete
–Technique
• Before adding any drill, the strength
and conditioning professional must
demonstrate proper technique to the
athlete.
• Proper landing technique is essential
to prevent injury and improve
performance in lower body
plyometrics.
Safety Considerations
• Physical Characteristics
–Clients weighing more than 220 pounds
may be at increased risk of injury
–Clients who are 220 pounds should
avoid high volume high intensity
plyometrics
–Clients weighing more than 220
pounds should not perform depth
jumps greater than 18 inches
Landing Position
• The shoulders are in
line with the knees,
which is accomplished
through dorsiflexion of
the ankle and flexion of
the knees and hips
• Knees track along the
toes
• This places your center
of gravity over the
body’s base of support.
• Do not land on your
toes or ball of your foot
Pre-training Evaluation: Strength
• Lower body plyometrics:
– You should be able to 1 RM squat 1.5 times your
BW
• Upper body plyometrics:
– You should be able to 1 RM bench press 1.0
times your BW if you weigh 220 lb and 1.5 times
your BW if you weigh less than 220 lb.
• An alternative is to perform 5 clap push ups
consecutively.
• If standards are not met plyometrics should be
delayed.
Pretraining Evaluation: Speed
• Lower Body Plyometrics:
–5 squat reps with 60% BW in 5
seconds or less for
• Upper Body Plyometrics:
–5 reps of bench press with 60% of
BW in 5 seconds or less
Pretraining Evaluation: Balance
•
•
•
•
Three balance tests are
listed in order of difficulty
Each test position must be
held for 30 seconds. Tests
should be performed on the
same surface used for
drills.
Beginners training with
plyometrics for the first time
must stand on one leg for
30 seconds without falling.
Advanced athletes must
maintain a single-leg half
squat for 30 seconds
without falling
Equipment and Facilities
• Training Area
• The amount of space needed depends on the
drill
• Most bounding and running drills require at least
30 m (33 yards) of straightaway, though some
drills may require a straightaway of 100 m (109
yards)
• For most standing, box, and depth jumps, only a
minimal surface area is needed, but the ceiling
height must be 3 to 4 m (9.8-13.1 feet) in order to
be adequate
Equipment
• Boxes for box
jumps must have
a non slip surface
• Boxes range from
6 to 42 inches
• Landing surface
of at least 18-24
inches
Landing Surface
• To prevent injuries the landing surface
should be shock absorbing
• Recommended Landing Surfaces:
• Concrete, Tile, or Hardwood Floors
are not Recommended
Proper Footwear
• Good ankle and arch support
• Good lateral stability
NSCA Power Guidelines
• Single–Effort Activity (i.e.power clean):
– 3-5 sets
– 1-2 reps
– 80%-90% Intensity
– 2-5 minutes of RI
• Multiple-Effort Activity (i.e.box jumps):
–
–
–
–
sets
reps
Intensity
minutes of RI