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Chhaya et al., Int J Med Res Health Sci. 2015;4(1):7-12
International Journal of Medical Research
&
Health Sciences
www.ijmrhs.com Volume 4 Issue 1 Coden: IJMRHS Copyright @2014 ISSN: 2319-5886
Received: 5th May 2014 Revised: 28th Oct 2014 Accepted: 31st Dec 2014
Research article
EFFECT OF PLYOMETRIC TRAINING ON VERTICAL JUMP HEIGHT IN HIGH SCHOOL
BASKETBALL PLAYERS: ARANDOMISED CONTROL TRIAL
*Chhaya Verma1, Lakshmi Subramanium2, Vijaya Krishnan3
1Professor of Physiotherapy, Seth G.S. Medical College & KEM Hospital, Parel, Mumbai
2M.P.Th, Ergonomic Consultant, Ergworks Inc, Banglore, India
3M.P.Th (musculoskeletal sciences), LTMMC & LTMGH, Sion, Mumbai
*Corresponding author email:victoryv2@yahoo.co.in
ABSTRACT
Background: Plyometric involve high intensity eccentric contraction immediately after a powerful concentric
contraction. A vertical leap in basketball also involves rapid & repeated muscle contraction & stretching. Various
methods have been used to improve the vertical leap in players, but only few studies mention about plyometrics.
Aim: To determine the effect of Plyometric training on vertical jump height in high school basketball players &
compare them with their untrained counterparts. Methods and Materials: 144 students were randomly selected
& distributed in Group I (Pre-pubertal) & Group II (Pubertal) which was further divided into Group A (trained
players) & Group B (untrained students). A gender wise distribution followed this. Plyometric training of 6 weeks
was conducted & the vertical jump height pre & post training were recorded & compared. Results: Vertical jump
height improved significantly post Plyometric in Group Bcompared to Group A. Boys showed improvement in
Group B, however girls were better in Group A. Correlation of BMI with vertical jump height was negative &
significant in Group B. Conclusion: Plyometric training brought significant change in untrained students. Boys
gained more jump height while girls showed significant increase in jump height during pubertal growth spurt.
Also, increased BMI reduced jump height.
Keywords: Basketball, Vertical jump height, Plyometric training, Body mass index.
INTRODUCTION
Basketball is one of the most popular team based
sport played and watched throughout the world. The
aim of the game is for each team to defend a goal area
while trying to score goals at the opposing end of the
court. The on court team of 5 players consists of 2
forwards, 2 guards and a centre with each player
having to play in attack and defence. Basketball
requires speed, explosive power and sustenance of
maximum performance throughout the game.1
Vertical Jump: is the act of raising one’s centre of
gravity higher in the vertical plane solely with the use
of one’s own muscles. The vertical jump is divided
into 2 types:
Standing vertical jump: refers to vertical jump
done from a standstill with no steps involved
Running Vertical jump: refers to vertical jump
after an approach or run to help add energy to the
jump in an effort to improve on the standing
vertical jump.2
Plyometric Training: Is an essential tool for
improving explosive force. Plyometric exercises are
defined as eccentric loading immediately followed by
a concentric contraction. 3
Neurophysiology:These exercises induce
neuromuscular adaptations to the stretch reflex,
elasticity of the muscle and golgi tendon organs. This
DOI: 10.5958/2319-5886.2015.00002.8
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Chhaya et al., Int J Med Res Health Sci. 2015;4(1):7-12
muscle action of eccentric to concentric or
deceleration to rapid acceleration is known as
Stretch-Shortening Cycle (SSC).4The conversion
from the negative (eccentric) to positive (concentric)
work is known as Amortization Phase. This begins at
the onset of eccentric contraction and continues to the
initiation of Concentric Contraction.5,6 Wilt suggested
that muscular performance gains after Plyometric
training are attributed to these neural adaptations and
it may enhance neuromuscular function.6,7
The shorter the duration of all the 3 phases, greater
will be the exploratory power of the muscles
exercised.Plyometric training is a training strategy
designed to improve the performance by
incorporating the basic needs of agility & power,
allows muscle to reach exponential increase in the
maximum strength & speed of movement inthe
shortest duration.8-11
Researchers have suggested that Plyometric exercises
were initially utilized to enhance sport performance
and more recently used in the rehabilitation of injured
athletes to help in preparation for a return to sport
participation.12 Santos et al in their study concluded
that Plyometric training showed positive effects on
upper & lower body explosive strength in adolescent
male basketball players.13Saggital plane Plyometric
program showed significant improvement in vertical
jump height in a study conducted by King & Cipriani,
on high-school basketball players. 14 A study done by
Mondal & Wondirad, to assess the effect of 6-week
Plyometric training on vertical jump performance
demonstrated a significant improvement in the
vertical jump performance of an athlete. 12 Also,
Abbas Asadi, in his study concluded that a 6-week in-
season Plyometric training program had positive
effects for improving power & agility, performance in
young male basketball players & his study further
provides support for coaches & players to use this
training method during competitive phase. 15
The purpose of this study, thus, was to determine the
effect of Plyometric training on vertical jump height
in high school basketball players compared to their
untrained counterparts around puberty. The effect of
training on boys & girls were also separately noted.
Aim: To determine the effect of 6-weeks of
Plyometric training on vertical jump height in high
school basketball players and untrained students
around puberty.
Objectives: 1. To compare the effect of Plyometric
training on vertical jump height between high school
basketball players and untrained students. 2. To
observe the effect of training on pre pubertal &
pubertal boys & girls. 3. To observe the effect of
Body Mass Index on vertical jump height.
MATERIAL AND METHODS
Study design: A randomized control trial
Study duration: 6 weeks
Sample size: 144
Location: Mumbai, Maharashtra, India
Inclusion criteria: Basketball players - boys and
girls from different schools in Mumbai who have
been playing the sport at a competitive level. 2 groups
of Pre-pubertal (10-11 yrs) and Pubertal (14-15 yrs)
were taken. Healthy active students (non basketball
players) of the same age and sex were included.
Exclusion criteria: Previous history of lower limb
injuries. Ligament and muscle injuries, boys and girls
who were unable to cope up with the training sessions
Fig. 1: Randomised distribution of subjects
Procedure: An institutional ethics committee
approval was obtained. A written consent from all the
participants along with prior permission from the
school principals was obtained. A musculoskeletal
screening of all the subjects was done. Measurement
of the height and weight was done and the Body Mass
Index was calculated.
Explosive power is the ability to exert a maximal
force in as short time as possible. Speed is the ability
to reproduce these explosive movements one after the
with minimal fatigue. Running speed is very
important in basketball players and it can be assessed
by sprint tests, shuttle tests etc.7
Subjects
(n=144)
Group I
(72) (10-
11 Years)
A
(Trained 36)
(i) Girls
(22)
(ii) Boys
(14)
B
(Untrained
36)
(i) Girls
(22)
(ii) Boys
(14)
Group II
(72) (14-
15 Years)
A
(Trained
36)
(i) Girls
(22)
(ii) Boys
(14)
B
(Untraine
d 36)
(i) Girls
(22)
(ii) Boys
(14)
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Chhaya et al., Int J Med Res Health Sci. 2015;4(1):7-12
Vertical jump height was measured pre and post
training. 16-18 The athlete stands on to a wall and
reaches up with the hand closest to the wall. The
point of the fingertips is marked keeping feet flat on
the ground. The athlete then jumps vertically as high
as possible and attempts to touch the wall at the
highest point of jump. The difference in the distance
between the reach height and jump height is the
score. The best of three attempts is recorded. Biceps
and triceps, as all major muscle groups in the body
are important for basketball. There are compound
movements that can be done to integrate an isolated
bicep or tricep exercise within other movements e.g.
Pull up, press ups. The pushing exercises incorporate
triceps while pulling exercises will incorporate the
biceps.
The subjects were put on a Plyometric training
program of 6 weeks, constituting the lower body19
and upper body20 Plyometric exercise.
Duration of a session: 40 minutes.
Frequency: 3 days/week (alternate days)
The training session consisted of: Warm up exercises:
10-15 minutes including stretching of hamstrings,
tendoachilles, illiopsoas, adductors and mobility
exercises of the lower limb. Also, stretching of
biceps, triceps, shoulder, pectorals, trunks were done.
Slow skipping and marching were included too.
Plyometric training: 20-25 minutes including arm
Plyometric and lower body Plyometric. Cool down:
10 minutes including slow jogging, walking, lying
down back stretch, deep breathing, and relaxation
Training program:
The untrained group was asked to perform the general
warm up prior to the vertical jump. Cool down
exercises were performed by them after the jump
height was recorded.
For trained group: the exercises included were-
Upper body Plyometric: Press-ups, Chest Pass, Power
Drop
Lower body Plyometric: Two-legged hops or Bunny
hops, Depth jumps, Short sprints or Bounds
Fig 2: Vertical Jump Test
RESULTS
Table 1: vertical jump height –pre & post training
Vertical jump height (cms)
Age
Trained/
untrained
Gender
Pre
mean
Post
mean
Post-
Premean
n
mean + sd
Pre-
Pubertal
group I
(10-11yrs)
Trained
girls
32.95
34.18
1.23
22
34.18 +1.38
boys
32.14
33.78
1.64
14
33.78 +1.28
Untrained
girls
32.77
34.09
1.32
22
34.09 +1.46
boys
28.14
31.07
2.93
14
31.07 +1.49
Pubertal
group II
(14-15yrs)
Trained
girls
31.45
33.36
1.91
22
33.36 +1.38
boys
35.17
35.57
1.21
14
35.57 +2.19
Untrained
girls
31.36
32.09
0.73
22
32.09 +3.51
boys
31.78
35.21
3.43
14
35.21 +1.99
Inference: There is an improvement seen in post training vertical jump height as compared to the pre-training in
all groups.
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Chhaya et al., Int J Med Res Health Sci. 2015;4(1):7-12
Table 2: Comparison of effect of Plyometric
training on vertical jump height (in cms) of
trained players & untrained students.
Girls
Boys
10-11 yrs
14-15 yrs
10-11 yrs
14-15 yrs
Trained
1.23
1.9
1.64
1.21
Untrained
1.32
0.73
2.93
3.43
p-value
0.83
0.15
0.02*
0.009*
Inference: Improvement in vertical jump height was
significantly greater in untrained boyscompared to
trained boys.
Table 3: Mean improvement between Boys &
Girls in Vertical Jump Height(in cms)
Gender
Trained
Untrained
10-11 yrs
14-15 yrs
10-11 yrs
14-15 yrs
girls
1.23
1.9
1.32
0.73
boys
1.64
1.21
2.93
3.42
p-value
0.37
0.25
0.003*
0.013*
Inference: Improvement in jump height is significant
in boys compared to girls in untrained group while in
the trained group girls are better than boys.
Table 4: Mean difference in Vertical Jump Height
between Pre Pubertal & Pubertal ages
Age
Girls
boys
trained
untrained
trained
untrained
pre-pubertal
(10-11 yrs)
1.22
1.32
1.64
2.92
pubertal
(14-15 yrs+a55)
1.9
0.73
1.21
3.42
p-value
0.1
0.47
0.5
0.45
Inference: There is no significant difference in the
pre-pubertal and pubertal age groups in vertical jump
height.
Table 5:Body Mass Index in Pre Pubertal &
Pubertal boys and girls
Age
Girls
Boys
Trained
Untrained
Trained
Untrained
Pre-pubertal
(10-11 yrs)
_0.4(0.06)
_0.49(0.02)
_0.12(0.49)
_0.5(0.05)
Pubertal
(14-15 yrs+a55)
0.113(0.6)
_0.490(0.02)
_0.172(0.55)
_0.32(0.2)
Inference: A significant negative correlation is seen
in the untrained boys and girls of both age groups
suggesting that as the BMI increases, the vertical
jump height decreases.
DISCUSSION
Vertical jump measurements are used primarily in
athletics to measure performance. The most common
sports in which this is measured are field and track
events, basketball, football, volleyball etc. This study
was conducted to evaluate the effects of 6 weeks
plyometric training on vertical jump height in high
school basketball players. It was also aimed at
determining the effect of the pre-training status,
gender and pubertal age on the difference in vertical
jump post plyometric training.
Kinetic forces involved during a vertical jump are6-
1. Contact time: Period of time for which the foot
/feet are in contact with the ground during an
activity. This phase is important, as the body
cannot generate force to increase velocity or
change directions without foot contact.
2. Ground reaction force (GRF): is the force exerted
by the ground on a body in contact with it.
3. Impulse: is the rate of change of momentum.
These above factors mentioned collectively
contribute to the quality of both the types of the
vertical jump: standing and running which are
enhanced during a plyometric training programme.
Table 1 demonstrates the significant improvement in
the jump height post plyometrics. The training effect
was seen to be enhanced in untrained students as
compared to trained players (Table 2). Neural
adaptations after training among initially untrained
individuals include earlier activation and increases in
maximal discharge rates of single motor
neuron.21But, in individuals with training
background, these neuromuscular adaptations have
already occurred. Therefore, the players showed
lesser improvements as compared to untrained
students.
The jump height is usually recorded as a distance
score. It can be affected by the angle of knee bending,
effective use of hands, co-ordination etc. hence, to
minimise these factors the students were given three
attempts to perform the test and the average of the
scores were recorded for analysis purpose.
Boy’s demonstrated increased vertical jump height
than Girls (Table3). This was due to the fact that
Boys demonstrated a neuromuscular spurt evidenced
by an increased vertical jump height and increased
ability to attenuate the landing force. 22 Also,
eccentric exercises are performed differently by girls
as compared to boys as they have different activation
pattern. Eccentric contractions induce a significant
post-exercise force deficit. It was observed that girls
showed greater loss of strength immediately after a
bout of maximal eccentric contraction due to muscle
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Chhaya et al., Int J Med Res Health Sci. 2015;4(1):7-12
thawing. 23 Since, plyometric exercises involve this
effect; the difference in activation patterns might also
have affected the final outcome in girls. There are
many ways to improve vertical jump, but the most
effective exercises include plyometrics along with
exercises that build both strength and power. For e.g.
Full squats, weighted step ups, overhead walking
lunges sprints, agility drills etc. the students can build
strength by performing basic weight training exercise
and build power with faster dynamic movements.
Also, practising maximum vertical jump will increase
the vertical jump.1,6
During and following puberty, boys have a significant
increase neuromuscular performance, while most
girls do not (Table 4).24 But specialized
neuromuscular training introduced at the onset of
puberty can influence these neuromuscular responses
in girls. These improved neuromuscular adaptations
due to our plyometric training could probably have
resulted in an enhanced improvement in pubertal
aged girls compared to boys.
An improvement in vertical jump is said to be
enhanced in the pubertal age group due to physiologic
growth spurt.23, 24 But in our study this effect was
seen only in trained pubertal aged girls. On an
average, girls begin the process of puberty about 1- 2
yrs earlier than boys.25Girls, therefore, attain their
adult height and growth spurt earlier than boys. All
girls in our study in the age group of 14 –15 yrs had
attained their menarche at least a year prior to the
start of the study and thus would be at the peak of
their growth spurt. This difference in the pubertal age
between boys and girls explains the absence of
significant improvement in vertical jump height in
pubertal aged boys.
It is easier for one’s propulsive muscles to carry one
faster and further if one’s body is lighter.26 Also,
greater the body mass, greater the ground reaction
force and lesser will be the velocity of the vertical
jump.2This reasons the negative correlation of BMI
with the jump height. In our study, a significantly
negative correlation is present in untrained students
as compared to trained players (Table 5). As the BMI
calculated from the weight would include both
muscle and fat mass, some individuals may have a
high BMI because of increased muscularity rather
than increased body fat.27-32
Increased muscularity especially in the lower limbs
would enhance power production and hence increase
vertical jump. This might be the cause of a significant
negative correlation seen in untrained subjects.
Pearson’s Correlation test was used for calculation
and is depicted in table 5.
CONCLUSION
This study concludes that plyometric training of 6
weeks brought a significant change in the vertical
jump height in untrained students as compared to
basketball players. Boys gained more jump height
compared to girls with training, however, during
pubertal growth spurt girls showed significant
increase in jump height. As Body Mass Index of a
person increases, vertical jump height decreases. This
correlation is however not significant for trained
individuals who have a higher BMI due to muscle
mass and not fat.
ACKNOWLEDGEMENT
We thank god almighty, the college dean, the prof &
head of physiotherapy department, the school
principals and all the students who participated in the
study.
Conflict of Interest: Nil
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