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Plyometric
Training for Youth
by
Donald A. Chu, Ph.D., PT, ATC, CSCS |
Plyometric
training is known to be an intense form of exercise that requires
maximal efforts to create the physiological change associated
with elite athletic performance. This system became popular
in the late 60's to the early 70's and was credited with being
responsible for much of the East European success in athletics
during that time. Since then, the use of plyometric training
has evolved into a mainstay of the training and development
programs of virtually all-sporting events. With this transition
came many questions, including the age, gender and strength
levels of the athletes who would benefit from this form of training.
This article is intended to deal with the use of plyometric
training and junior athletes, both pre-and post-pubescent.
The fundamental reason to train with plyometrics is to reduce
the ground contact time that an athlete spends when running
or jumping. This time is reduced as the athlete matures, gets
stronger, and practices the skills of their game. To further
enhance resistance training the athlete spends considerable
time practicing the specific movement skills they wish to improve;
namely, running and jumping. These two movement patterns are
often thought of as genetic endowments and affected little by
outside influences such as training programs. To the contrary,
research has shown that virtually all athletes can positively
influence their performance outcomes by using plyometric training
on a regular basis.
In order to implement this type of training with young athletes
several factors must be considered. The first consideration
is what controlled research studies tell us about this form
of training and its effect on young children. Currently, there
is little peer- reviewed research to explain the effects of
this form of training available in the literature.
Avery Fagenbaum Ph.D. from the University of Massachusetts is
currently studying two groups of children who participate in
their "Youth Strength Training" programs offered through their
Department of Kinesiology. The groups are combining plyometric
training with strength training and using "games" to provide
cardiovascular conditioning. Pilot studies indicate that jump
training, in combination with resistance training, has resulted
in significant increases in jump and reach scores and long jump
scores over groups that strength train alone.
One of the reasons why this type of result might occur is the
learning ability of the young child to react to the stimulus
of ground contact. It is well documented and a matter of practice
that children learn to play skill games such as tennis and baseball
at ages as young as 6-8 years. The application of these types
of activities with children has long been utilized to develop
hand-eye coordination specific to these games. East European
researchers have published research to support that 6-8 years
is an excellent time to initiate these types of activities because
the nervous system is "plastic" and youngsters can capitalize
on motor learning to develop their game skills. What is equally
important but often overlooked is that movement skills involving
the lower extremities are extremely important in developing
"athleticism". Therefore, plyometric or "jump training" can
play a critical role in the development of athletic ability
in the young athlete.
When designing the plyometric training program for youth we
must consider the same program variables that are considered
in any exercise prescription. Volume, intensity, frequency,
and recovery, as well as, progression, must be manipulated to
suit the needs of the younger performer.
Footwork Drills
A unique form of footwork drills that are "plyometric
in nature" and lend themselves to being extremely suitable for
beginning athletes have been presented by John Frappier M.S.,
Exercise Physiologist from Fargo, North Dakota in the USA. The
format includes utilization of one of several footwork patterns.
These are known as the four-square, eight-square, Munoz, and
Krumrie patterns. The latter two are named for former NFL football
players who helped to develop them.
The drills are used to teach a young athlete how to move the
feet out from under the body's center of gravity (C of G) and
recover, allowing the athlete to be in a balanced position when
the feet quickly recover to maintain dynamic balance. This is
extremely useful in teaching the younger athlete to maintain
balance and stability of the C of G while allowing the feet
to change direction and adjust to a changing base of support.
This is very specific to on-court or field adjustments that
must be made quickly and without a great deal of conscious thought.
The general rule for all patterns is to count "one" each time
the athlete returns to the starting point. For example, when
executing a four-square drill and going from box 1 to box 2,
the coach counts each time the athlete's foot or feet return
to box 1. For patterns such as the 1-2-3 pattern (multiple boxes)
again count "one" when the athlete returns to the starting box.
These repetitions are totaled for a specific time period (such
as 5-10 seconds) and recorder for future comparisons. Although
Frappier offers specific routines that have been developed over
time, the reader is limited only by their own imagination as
to how to develop various routines. The examples that are shown
here merely serve as models for this form of exercise.
Volume of Plyometric Training for Youth
There is little to substantiate the exact requirements
for calculating appropriate volumes for novice athletes. The
following represent "guidelines" that should be observed when
prescribing exercise for this group of athletes.
1. Consider the athlete. If they are young and inexperienced,
remember that there will be a learning curve associated with
any exercise drill. Several sessions of training should be utilized
to teach appropriate execution of the drill. The learning curve
is very rapid for this age group, and proper execution is much
more important than the number of repetitions achieved.
2. Observe the execution of the drill. Fatigue is the
biggest detractor of execution; it interferes not only with
performance of the drill it impedes learning as well. When execution
falls below an acceptable level, stop the drill. It is far more
important to see a drill performed correctly than to perform
repetition for the sake of repetition.
3. Focus and concentration of youth is limited. The younger
the athlete, the more likely they are to mentally wander during
the course of a training session. It is best to perform fewer
drills correctly than more drills incorrectly. Pre-planning
is essential, the coach should consider which biomechanical
traits (vertical jump, linear jump, change-of-direction) they
would like to develop prior to beginning a training session.
This allows for selection of exercises prior to practice and
sets a plan of training into motion.
Intensity of Plyometric Training for Youth
Intensity of plyometric exercises is determined by "effort
of execution". Jumping drills that require maximal distance
or height to be achieved is going to be higher in intensity
that efforts such as put forth during the footwork drills previously
described. Avery Fagenbaum has demonstrated in his studies at
the University of Massachusetts that utilizing a 4" box as the
maximal height utilized in the performance of jumping drills
consisting of moving on and off the box was sufficient to achieve
statistically significant results in vertical jump improvement.
Apparently, athletes as young as 6-8 can still physically benefit
from a drill using relatively lower heights.
Maximal efforts should be utilized once the youngster has mastered
the execution of the drill. Once the learning phase has been
accomplished the athlete is much more likely to direct their
efforts at force development along appropriate lines. The result
will be a movement that has the subjective quality of "ease
of execution", "flowing movement" and/or "powerful effort".
Frequency of Plyometric Training for Youth
Traditional thinking on plyometric training discusses
the need to perform maximal effort days twice within a training
week. This tends to allow for a recovery period of 48-72 hours
of recovery between training days. When working with juniors,
it is inadvisable that truly maximal days of training occur
until they have accomplished all the learning, execution and
adaptation necessary to perform maximal effort exercise.
With this in mind, it is acceptable to have a higher frequency
pattern for plyometric training days. Three days a week are
perfectly acceptable for juniors, given that there are not competition
days at the end of each weekly cycle of training. If there are
competition days included within the week or on the weekend,
then the frequency of plyometric training should be reduced
to twice a week.
If an active, formal warm-up is being conducted as part of each
workout it is also acceptable to include 4-5 plyometric exercises
within the context of the warm-up routine, rather than having
a formal workout for a particular day. This gives the coach
the opportunity to expose all of the athletes in a group to
the same drills. It is also an opportunity to prescribe the
number of repetitions, or time allotted to the performance of
each drill. This sort of planning helps in the administration
of plyometric training programs.
Recovery in Plyometric Training of Youth
The effects of fatigue on plyometric training have been
previously mentioned. Fatigue is most likely to occur when the
junior athlete is asked to perform exercises that do allow for
full recovery between execution of repetitions. Without full
recovery, the muscular and nervous system does not have the
opportunity to rid the systems of the effects of fatigue metabolites
and will result in a decrement in performance. This decrement
will serve to frustrate the athlete and the coach because of
an inability to achieve desired efforts as measured by speed,
distances, or heights. Learning new skills will be impeded for
the same reasons.
The level of metabolism that should be utilized when performing
these types of workouts is the ATP-PC and Anaerobic glycolytic
systems. These metabolic systems require brief, intense work
periods, followed by long (5-30X/work) active recovery periods.
Jogging, walking, moving about are all acceptable forms of active
recovery between repetitions of effort. It is well documented
that active recovery is a more effective method of clearing
the systems in preparation for the next work bout.
Progression in Plyometric Training of Youth
Progression in learning of plyometric exercises includes,
but is not limited to, drills that are increasingly more complex.
As an example, straight depth jumps as compared to depth jumps
with 180 degrees of body rotation. It is imperative that the
coach be able to biomechanically determine the required traits
of their particular sport. An example would be the net ball
coach who decides that vertical jump is a priority and that
the best way to improve that skill is to train using exercises
that are specific to the particular tasks of shooting and rebounding.
Progression can take the form of increasing the range of motion
that a particular task requires. For example, the average angle
at the knee used during the take-off in many events is approximately
140 degrees. This is what is termed a "short-amplitude" jump,
a progression might be to advance to using "long-amplitude"
jumps where there is a 90 degree angle at the knee achieved.
Each has a particular purpose, and places a different demand
on the athletes' body. Long amplitude jumping activities are
most valuable for those athletes involved in Olympic weight
lifting, Free-style and Greco-Roman wrestling, and Rugby.
Another form of progression includes increases in intensity
of exercise for a specific exercise. Using hurdles of different
heights serves to challenge the limits of each athlete. These
changes in the height of hurdles or the distances covered represent
advancement in the effort and complexity of task. The coach
must be able to recognize the individual needs of the athlete
and to design appropriate challenges that teach the athlete
to respond quickly to the ground and reduce the amortization
phase. This should be done without making the task so difficult
that the athlete cannot react quickly to ground contact.
Summary
The use of plyometric training in younger athletes has
proven itself to be successful in improving their vertical and
linear jump capabilities. Younger athletes are capable of performing
plyometrics safely and effectively.
(Before
beginning any exercise program consult with your physician.) |
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