•.
I
CALIFORNIA STATE UNIVERSITY, NORTHRIDGE
THE EFFECTS OF SKILL-SIMULATED ISOKINETIC
1\
TRAINING ON THE ACCURACY AND VELOCITY OF THE
INSTEP DRIVE KICK
A thesis submitted in partial satisfaction of the
requirements for the degree of Master of Arts in
Physical Education
by
Nathan Wright
June, 1979
The Thesis of Nathan Wright is approved:
(Dr. Darrel Guthrie)
(Dr.
(Dr. Adran Adams, Committee Chairperson)
California State University, Northridge
ii
ACKNOWLEDGMENTS
The author wishes to use this opportunity to offer
praise and appreciation to the individuals who provided
valuable assistance throughout the.course of this investigation.
Dr. Adran Adams, Committee Chairperson, for his
constructive suggestions in design formulation and
overwhelming support throughout this investigation.
Dr. Darrel Guthrie, for his guidance and constructive suggestions throughout this investigation.
Dr. Barry Devine, for his guidance and constructive
suggestions throughout this investigation.
My wife Debbie, deepest appreciation for her
support.
iii
TABLE OF CONTENTS
Page
ACKNOWLEDGMENTS.
iii
LIST OF TABLES
vi
ABSTRACT
viii
CHAPTER
I.
INTRODUCTION.
1
The Problem
Statement of the Problem
The Hypothesis
Importance of the Study
Assumptions
Definition of Terms
II.
REVIEW OF RELATED LITERATURE.
6
Physiology and Principles of Strength
Programs
General Training Principles
Biomechanical Relationships Within the Study
Strength Relationships and Training Effects
Relationships of Strength Training on
Specific Sport Activities
Summary of Review
III.
RESEARCH METHOD AND DESIGN . .
29
General Design
Selection and Orientation of Subjects
Pilot Study
Equipment
Shooting Tests
Strength Tests
Training Program
IV.
ANALYSIS OF THE DATA.
Summary of Major Findings
iv
42
~'·
V.
SUMMARY, FINDINGS AND RECOMMENDATIONS . .
~
. .
59
Summary
Findings
Conclusion
Recommendation.s
BIBLIOGRAPHY . . . . . .
64
v
LIST OF TABLES
Page
TABLES
A.
TABLE I.
.
.
.
45
Test-Retest Reliability for Speed and
Accuracy on Soccer Kicking
B.
TABLE II .
.
46
.
A Comparison of the Three Experimental
Groups on the Pre-Test
c.
TABLE III.
47
.
Significance of the Difference Between the
Three Experimental Groups on the PreTest, Using Mean Scores for Accuracy
D.
TABLE IV
48
Significance of the Difference Between the
Three Experimental Groups on the MidTest, Using Mean Scores for Accuracy
E.
TABLE V.
49
Significance of the Difference Between the
Three Experimental Groups on the PostTest, Using Mean Scores for Accuracy
F.
51
TABLE VI
Significance of the Difference Between the
Three Experimental Groups on the PreTest, Using Mean Scores for Speed
G.
TABLE VII . . . . .
52
Significance of the Difference Between the
Three Experimental Groups on the MidTest, Using Mean Scores for Speed
vi
Page
H.
TABLE VIII . . . . .
. . . . .. . . . . . .
53
Significance of the Difference Between the
Three Experimental Groups on the PostTest, Using Mean Scores for Speed
I.
55
TABLE IX
The Significance of the Difference Within
the Experimental Groups Between the PreTest, and Post-Test, Using Mean Scores
for Accuracy
J.
TABLE X. . . . . . . .
The Significance of the Difference Within
the Experimental Groups Between the PreTest, and Post-Test, Using Mean Scores
for Speed
vii
56
ABSTRACT
THE EFFECTS OF SKILL-SIMULATED ISOKINETIC
TRAINING ON THE ACCURACY AND VELOCITY OF THE
INSTEP DRIVE KICK
by
Nathan Wright
Master of Arts in Physical Education
Thirty-six male volunteers from Los Angeles Baptist
College were divided into three equal size groups for the
purpose of investigating the effects of skill-simulated
isokinetic training on the accuracy and velocity of
the instep drive soccer kick.
It was hypothesized that by exercising through a full
range of motion with maximum speed in simulated body
position, the use of an isokinetic training instrument
would result in improvement of accuracy and increased
velocity in kicking a soccer ball.
All of the subjects
were given a pre-test to determine their beginning
ability for speed and accuracy in kicking
viii
a soccer ball.
The subjects were also retested at the
middle and end of the study to determine if any significant
results developed.
The subjects were placed in one of the
following three. groups based upon matched groupings of
z
scores; isokinetic group G , isokinetic and goal shooting
1
group G , and_ goal shooting group G .
2
3
The study lasted
for six weeks.
The hypothesis, which stated that there would be
improvement of accuracy and increased velocity in kicking a
soccer ball, while training with an isokinetic training
device, was accepted at significant levels with the right
foot for accuracy.
The left foot showed improvement, but
not at an acceptable significant level for accuracy and
therefore the hypothesis concerning significant improvement of accuracy between pre-test and post-test scoring
for this group was rejected.
The pre-test/post-test analysis of the right and left
foot for velocity showed improvement, but they were not
significant at an acceptable level of confidence within
. groups.
The hypothesis was rejected for all other tests
between groups with regard to velocity and accuracy using
either foot.
Slight improvement was shown, but not at any
significant level of confidence.
ix
CHAPTER I
THE PROBLEM AREA
INTRODUCTION
Physical strength, muscular endurance, and neuromuscular skills are three main components of athletic
performance.
Of these components, neuromuscular
skill is usually the factor that determines the difference
between uncoordinated and coordinated action.
Physical
strength and muscular endurance add greatly to producing
desired motion with any type of consistency in
a
skillful
movement.
Neuromuscular skill determines
control of body movements.
~he
accuracy and
Precision in movement
involving accuracy involves exact and delicate control
of body movements.
This is exemplified in skills of
throwing, hitting, striking, and kicking.
Also, these
acts include exactness in point of contact and lines of
force.
A present trend in physical education has been to
exercise a group of muscles in the plane of movement
required to perform a motor skill while using resistance exercises.
To perform a motor skill with resis-
tance, the development of coordinated motor skilled
1
2
movements and task specificity in training are needed.
Task specificity in training refers to doing a
particular activity or movement, such
a~
kicking, in
simulating the actual movement pattern performed within
a skill.
Factors of range of motion, control of resis-
tance, and body position are necessary considerations.
Isokinetic instruments provide maximum resistance to
the muscles at all points in the range of motion, and
can be performed at different speeds through the entire
range of motion.
Isokinetic exercisers are based upon the
control of speed during contraction rather than the amount
of load (isotonic) or effect at a given angle (isometric).
Therefore, the resisting force is always proportional to
the magnitude of the input of speed of actions.
Many coaches are concerned with consistency as related
to accuracy and skilled body movement.
This study was an
attempt to test an isokinetic exerciser for the improvement of accuracy and sp.eed in kicking a soccer ball.
STATEMENT OF THE PROBLEM
The problem of this study was to determine the
effects of an isokinetic exercise device on the development of speed and accuracy of the instep drive soccer
kick.
~'·
STATEMENT OF THE PURPOSE
The purpose of the study was to investigate the
effects of isokinetic training on speed and accuracy of
kicking a soccer ball with the instep drive soccer kick.
HYPOTHESIS
This investigation was designed to test the following
hypothesis:
that by exercising through a full range of
motion with maximum speed in simulated body position,
the use of isokinetic training instruments would result
in improved accuracy and increased velocity in kicking a
soccer ball when using either foot.
IMPORTANCE OF STUDY
Soccer is becoming a popular sport in America.
It
is a sport not only of strength and endurance, but of
much skill and control of body movement.
Considerable
practice is needed before a person can acquire the skill
involved in this sport.
With the increase of competition
among youth soccer organization, high school teams,
college teams, and professional organizations, the demand
for more skilled soccer players exists.
With the increase
of competition the need for improving performance of
athletes is critical.
This study was designed to deter-
mine if use of an isokinetic exerciser is a valid
activity for developing soccer skills.
It is possible
q;;<}'·
that time would be better spent with the isokinetic
instrument when trying to develop kicking skills.
Since
the instep kick is a basic kick in soccer, and accuracy
with velocity is a factor in kicking goals and in
various types of passes and other kicking opportunities
in the game of·soccer, further improvement of this skill
is important.
Much of the improvement of soccer players in kicking
a soccer ball has been through constant playing with a
soccer ball.
This study investigates the specifics of
isokinetic training as an aid to the improvement of
soccer kicking using the instep drive kick.
LIMITATIONS
This study was limited by the following factor:
Physical activity other than working with
the Isokinetic Exerciser lBOX was not controlled.
ASSUMPTIONS
It was assumed that all subjects would give maximum
effort in each testing and training session and were
motivated equally on a verbal basis by the investigator.
DEFINITION OF TERMS
Accuracy.
The numerical value assigned each kick
according to the kicker's ability to hit the target used
in this study.
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5
Target.
A green colored canvas stretched between
a wooden structure of two by four inch wood.
Size of the
target was nine feet qy nine feet, with areas of scoring
upon it.
Details of the target are discussed in the
equipment section.
Instep drive kick.
A basic kick in soccer in which
the anterior surface of the foot from the toes to the
ankle of the lace portion of the shoe is used in contacting the soccer ball.
Isokinetic exercise.
Is based upon the control of
speed during contraction rather than the amount of load
(isotonic) or effect at a given angle (isometric).
Iso-
kinetic instruments provide a range of speeds under the
assumption that each speed provides for some resistance
along the total range of movement.
Shooting.
This term refers to the use of the foot
when striking the ball to propel it toward the target.
Power.
ball.
The application of force in kicking a soccer
6
CHAPTER II
REVIEW OF THE LITERATURE
Introduction
Conclusive research findings clearly indicate that
performance in athletics improves with strength training
programs.
Research relating to theories of strength
training programs and available research is presented
in the following four sections:
Section I:
1) physio-
logical basis of muscular strength, endurance, speed,
and power, and 2) general training principles.
II:
the biomechanics of a kicking action.
Section
Section III:
literature concerning the relationships between strength
and speed, power and endurance, and strength training
programs in connection with these variables.
Section IV:
the effects of strength training programs and the relationship to specific sport skills and activities.
Section I
Physiology and Principles of Strength Programs
Research studies investigating strength identified
two types of fibers and the twitch contraction time of
the fiber.
A fiber that completes a total contraction
rapidly, is labeled a fast twitch fiber.
A fiber that
7
completes·a contraction at a slower rate, is labeled a
slow twitch fiber (27).
Activities needing short, power-
ful bursts of contraction such as basketball, soccer,
swimming, track and field, and other team sports, utilize
a predominance of fast twitch fibers (27).
However, the
slow twitch fibers are better adapted for endurance
events that require repetitive contractions over a prolonged period of time (19).
These events include
distance running, distance swimming, canoeing, rowing,
cycling, skiing, and the sustained running action of team
sports such as basketball and soccer.
Edstrom and Ekblom (17) summarized the two types of
fiber as follows; 1) fibers with a high or intermediate
concentration of oxidative enzymes and a low concentration
of phosphorylase and myofibrillar ATP-ase, are generally
called Type I or Red Fibers (slow twitch fibers), and 2)
fibers with a low concentration of oxidative enzymes and
a high concentration of. phosphorylase and myofibrillar
ATP-ase are generally called Type II or White Fibers
(fast twitch fibers).
Gollnick (19) determined that in most individuals
fast twitch fibers are larger than slow twitch fibers.
He compared the enzyme activity and fiber composition
in the skeletal muscle of untrained and trained men.
Activitie~
and the histochemical identification of fiber
.,..
%'<>'·
~~-
8
,.
types and localization of oxidative activity were determined on biopsy samples from the vastus lateralis and
deltoid muscles of 74 individuals.
The subjects were of
different ages and state of physical training, some of
whom were participating in various sport activities.
Slow twitch fibers predominated in the muscles of the
endurance activities.
Both fiber types showed greater
oxidative capacity in the endurance athletes tested.
For the most part it appeared that with some types of
training, an enlargement of either fiber type could
occur.
Ariel (1) states (based on the above information)
that the body may select different muscle fiber types
within the same muscle depending upon the activity.
For
example, long distance running, an endurance activity,
may utilize different muscle fibers than an explosive
athletic event such as jumping or throwing.
He concluded
that a coach should consider divising training programs
that develop a specific muscle group for a specific
activity.
Saltin (38) observed in a study of metabolic fundamentals in exercise that different groups of athletes
participating in endurance events have a majority of
slow twitch fibers, however, weight lifters appeared to
have 50 percent of each fiber type.
Saltin suggested
'
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9
that differences in fiber composition between groups of
athletes may be due to natural selection and that the
talent of a particular athlete might be determined by
muscle biopsy before his selection to a particular event.
Ariel (1) through a personal communication at the
World Congress of Sport Medicine at Melbourne, Australia
in 1974, discussed the following research findings about
fast twitch muscle fibers; 1) it was found that the
intensity of the exercise is the prime factor in
recruiting the fast twitch fibers, and 2) since the
intensity of muscular performance varies throughout the
range of motion of joints, it is almost impossible to
exercise the fast twitch fibers throughout the range of
motion unless accommodated by resistance throughout the
exercise.
The following considerations were outlined based on
the above statements by Ariel (1); 1) It is important to
identify the dominant muscle groups involved in the
particular activity.
This can be accomplished by the
computerized biomechanical analysis method described
elsewhere (1,2), 2) It is important to exercise the
specific muscle groups with an exercise machine which
provides a full range of motion and in the proper
direction with minimal resisting force, and 3) The
resistance to the muscle should be applied throughout the
10
range of motion with the specific velocity for simulating
the activity as nearly as possible.
Specificity of Speed
Specificity of training in relationship to specific
velocity or speed of exercise is reviewed in the next
portion of section one.
Hellebrandt and Houtz (21)
related the general concepts to strength, speed, and
specificity with the following factors.
They reported
that mere repetition of contractions which place no
stress on the neuromuscular system has little effect on
the functional capacity of the skeletal muscles.
There-
fore, the amount of work done per unit of time was found
to be the critical variable upon which extension of the
limits of performance depends.
The speed with which
functional capacity increases implies that both the
central nervous system as well as the contractile system
are contributing components of training.
In conclusion,
they stated, weight tra;ining programs should consider the
following factors:
1) the resistance exercise should be
performed with explosive repetitions, and 2) the resistance exercise should be performed using multiple joint
motion.
According to Berger (4), an increase in strength
permits more weight to be lifted, while a faster appli-
- - - -~- '£<::-'·
11
cation of strength permits a greater propulsion of an
external object.
The rate of doing work or force (mass
times acceleration) times velocity affects the force of
an action.
This force can be a significant variable in a
successful performance of athletic skills as in the
ability to propel an external object (6).
Although an
increase in force will improve power, the assumption cannot be made that the strongest athlete will always have
more power, because the weaker athlete may be able to
contract his muscles faster (6).
As velocity is increased, the maximum contraction
force is reduced because of an inverse relationship
between muscle force and speed of movement which was
revealed by the research of Berger (6).
Most sport move-
ments are performed in less than two point five seconds
or they don't involve primary isotonic forces.
Therefore,
the maximum potential force is not usually achieved in a
fast movement.
Athletic skills tend to be more related to
the ability to effect the greatest force within a brief
time interval, rather than to maximum strength (6).
Moffroid (32) conducted a study to determine the
specific effects of two different training speeds on
muscular endurance and muscular force.
Two training
programs were administered to two different groups at
slow maximal exercise (low power) and rapid maximal
~···
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-
-
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\19)'·
-~-
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12
exercise (high power).
A control group constituted a
third dimension and received no exercise.
An isokinetic
device was used to provide for reciprocal exercise.
The
exercise groups exercised maximal knee flexion and knee
extension.
Each exercise group exercised either at a
slow speed (six revolutions per minute) or at a fast
speed (eighteen revolutions per minute).
Measurements of
peak torque for the quadriceps and for the hamstrings
were measured at different velocities of contraction.
Speed of exercise was found to be specific for muscular
endurance and for force increases at and below the
exercise speed.
From the above study, Moffroid (32) concluded that
power is the variable upon which extension of the limits
of performance depends, when related to speed.
The
amount of work done is not as important as the rate at
which it is done and exercise speed_ is specific in the
following ways:
1) low power (low speed, high load)
exercise produces greater increases in muscular force
only at slow speeds, 2) high power (high speed, low load)
exercise produces increases in muscular force at all
speeds of contraction at and below the training speed,
and 3) high power exercise increases muscular endurance
at high speeds more than does slow power exercise increase
muscular endurance at slow speeds.
13
Fulton (18) and Solley (39) concluded from their
study of speed in practice that early emphasis on speed
is more beneficial if it is the major factor in final
performance.
However, if both speed and accuracy are of
major importance, then an early emphasis on both seemed
more effective.
A further study was made by Sage (37)
to determine the effects of progressive and gradually
increasing speed practice on motor skill by using a
pursuit rotor.
A total of forty-eight subjects were
randomly assigned to one of four groups with four
different speed practice conditions.
Three of the four
groups practiced using gradually increasing speeds while
the fourth group (control group) practiced at a criterion
speed.
Results of the study were as follows:
1) Using
a continuous motor task, there are no major differences
in transfer performance between a group that practiced at
gradual and progressive speed increments and one that
practices at the criterion speed throughout the pretransfer practice period, and 2) as pre-transfer training
approaches the criterion speed, transfer scores of subjects trained by different methods are not significantly
different.
Fulton (18) chose a ballistic movement to study the
speed and accuracy involved in learning a movement in its
initial stages.
Subjects were subjected to hitting a
14
small rubber ball projected at a given height for two
training periods weekly for eight weeks.
An accuracy
group retarded its speed of movement until a high level
of accuracy group could be attained and the speed group
maintained maximum speed as an integral part of the movement and training.
Results indicated that the accuracy
group developed accuracy to a greater extent than did the
group which made speed of stroke the primary aim.
How-
ever, the total speed of the strokes of the groups in the
final training period were approximately the same.
Jensen (26) states that it is very important for the
performer to practice for accuracy in performance.
In
most competitive conditions, skills are performed with
maximum effort and high speed, however, accuracy in such
skills is dependent upon judgement of speed, distance, and
time.
Accommodating resistance (control of the velocity at
which the muscle contracts), allows one the development
of some added tension by the performer throughout the
full range of motion (34).
Thistle (42) found significant
increases in muscular strength through accommodating
re~
sistance procedures while using an isokinetic exercise
device.
Fifty-one normal subjects were used in his study
over an eight week period, he compared isokinetic contraction with standard resistive exercise techniques of
---~··
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15
isotonic and isometric contraction.
Concluding remarks
suggested that isokinetic training methods were more than
an efficient means of strengthening muscles.
In an investigative study of isokinetic exercise,
Moffroid (32) determined the reliability and validity for
measurements of torque, work, range ofmotion, and power.
Norms were set using the quadriceps and hamstring muscle
groups and force through the range of motion at varying
speeds of contractions was evaluated.
Results of the
usefulness of isokinetic exercise suggested the following
findings:
1) Isokinetic exercise can be an effective
means of increasing muscular torque throughout an arc of
motion, 2) Isokinetic exercise increases the work a muscle
can do more rapidly than does isometric exercise using
pulleys, 3) Muscular response to different loading systems
tends to be specific; that is, a muscle which is overloaded in a partial range of motion will increase significantly more in this range than in other, less exercised
joint positions.
In considering the principle notion of "specificity"
of training in relation to strength training and performance benefits, DeVries (16) states that development is
specific to the angle at which the greatest resistance is
applied.
Furthermore, strength measurements tested at
angles other than that at which isotonic training
16
took place may show gains less than fifty percent of that
at the exercised angle.
General Training Principles
Berger (7) investigated training a muscle at its
maximum load capacity by utilizing a procedure that
provided maximum load for ten repetitions.
The testing
procedure consisted of training two groups of men on ten
repetitions maximums.
One group trained with ten reps
per set, while the other trained with one-repetition
maximum for ten sets.
Results showed that the group
training at a one-repetition maximum for the ten sets
increased their strength significantly more than the
group that trained with the standard ten repetition
maximum set.
A reasonable assumption could be that train-
ing at a maximum intensity will produce maximal strength
gains.
In another study, Berger (6) investigated training
using one-repetition maximum as his criterion for
strength.
Training groups trained at two, four, six,
eight, ten, and twelve repetitions for each set.
Findings
indicated that those training with four, six and eight
repetitions showed greater gains in strength than the
group training with two, ten, or twelve repetitions.
work suggested that the closer you work at maximal
His
17
strength values, the greater your increase in strength
will be.
However, an individual is rarely able to main-
tain a maximal contraction more than onGe with constant
resistance, because after the initial force exertion,
the person is unable to lift a constant weight again
because of his decreased ability to generate force (6).
Pipes (35) states that isokinetics is becoming a
better method for building strength, because it affords
the advantage of a variable resistance which allows the
development of greater tension by the performer throughout the full range of motion.
In the traditional isotonic
exercise, however, the fixed resistance actually becomes
a reduced resistance as the movement progresses.
Jensen
(26) establishes the following universal points in building strength, which supports the advantage of using isokinetic training:
1) Exercises must be selected to work
the specific muscles in which strength is to be developed,
because significant strength gains result only in exercised muscles, 2) Muscles should be contracted regularly
(every second day) against heavy resistance, 3) Nearmaximum weight for few repetitions (four - to eight)
should be used, and 4) As strength increases, the
weight
must be progressively increased to provide continual overloading of the muscles (progressive resistance).
YC ____________ _
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18
Section II
Biomechanical Relationships Within The Study
Berger (4) states that exercise should be based on
the specific movement for which power is desired.
There-
fore, this movement will indicate the muscles that have
to be strengthened.
For example; 1) a high jumper exer-
cises for strength in hip and knee extensors and hip
flexors, 2) a football player exercises his back muscles,
hip and knee extensors.
Best results are gained by exer-
cising muscles directly used in the movement of each
specific sport.
Roberts (36) states that kicking is essentially a
variation of running.
Rotation of the pelvis precedes
joint actions in the swinging limb as in running.
In
beginning a kick, the kicking leg flexes at the knee until
the leg begins to rotate due to hip flexion.
When the
knee extension starts and accelerates, the leg gains
speed.
While the leg gains speed, the thigh begins to
slow and almost stop.
Once the thigh is past the perpen-
dicular, knee extension starts and is the chief contributor to speed at and through contact.
Placement of the supporting foot in kicking a soccer
ball is very important.
If it is placed too far forward,
then less momentum can build up.
If it is placed too far
~···
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V\1)>'·
19
behind the ball, then maximum force in the kick will be
spent before contact can be made (26).
The placement
of the supporting foot does vary somewhat, due to
individual differences in the kicking form of athletes
(24).
Section III
Strength Relationships and Training Effects
The first part of this section will sample the
studies correlating strength with speed and power.
The
second part will review experimental investigations
involving isokinetic strength training as related to
isotonic andjor isometric training.
Speed, power, and
muscular endurance will be the criteria measures of the
second part.
Wilkins (46) studied the effects of weight training
on speed of movements by employing a bicycle crank to
record the number of revolutions the subjects could turn.
His concluding statements were:
1) Weight training, over
a period of one semester, has no
~lowing
effect on speed
of arm movement as measured, 2) A semester program of
weight training does not increase speed of movement more
than a semester of beginning swimming or golfing, 3) Results suggest that daily training with weights may
improve muscular endurance.
20
Pierson and Rasch (33) conducted a study to strengthen
the muscles of the arms and shoulders.
After a four week
period post-test, scores showed significant increases in
strength, however, there was no significant increase in
the speed of elbow extension.
Masley, Hairabedian, and Donaldson (28) used two
control groups and an experimental weight training group
to determine whether increased strength through weight
training is accompanied by an increase in muscular
coordination and speed o.f movement.
Speed of movement was
measured by arm-cranking speed and a fencing foil was
used to measure coordination through the accuracy of
fifty thrusts.
The study was comprised of three groups;
1) a sport lecture class, 2) a beginning volleyball class,
and 3) a weight training group stressing overall body
building.
Results of the study indicated the following:
1) A six week weight training period increased strength
more than a similar period of volleyball or inactivity,
2) There was a larger increase in speed and co-ordination
from weight training than from volleyball or inactivity,
and 3) increased strength through weight training is
apparently associated with increased muscular co-ordination and speed of movement.
Capen (9) compared the effects of a weight training
program and a conditioning program on the development of
21
muscular power.
One group performed TOurteen exercises
in a progressive weight training program, while a second
group
partic~pated
in a conditioning course consisting
of tumbling, bag relays, and running for.two weeks; hard
combative lifts and carries as well as running for three
weeks; and conditioning gymnastics for five weeks.
To
measure muscular power, the standing long jump was used.
Results showed that the weight trainersimproved significantly more than the non-weight trainers.
Also, the
testing indicated that weight training did not produce
any detrimental effects commonly associated with muscle
tightness.
Chui (10) did a study that measu.red muscular power
on the vertical jump, the standing long jump and standing
shot-put.
Comparisons were between a non-weight training
group and a weight training group.
The weight training
group used barbells and dumbbells in a complete training
program.
Results were :pot significant even though the
weight training group improved on all tests more than
the non-weight training group.
Zorbas and Karpovich (47) investigated the speed of
movement using a single arm turning crank in a frontal
plane to determine whether heavy weight training would
lead to slower muscle contraction.
In a cross-sectional
study, they compared 300 weight lifters and body builders
22
with 300 non-weight lifting college students.
Results
indicated that the weight lifting group was significantly
faster than the control group, suggesting that heavy
weight training did not lead to slower muscle contraction
and probably would not be detrimental to performance of
speed-related athletic skills.
Clarke and Henry (13) investigated arm strength,
effective arm mass, and speed in a lateral adductive arm
movement.
Subjects consisted of an experimental group
that performed twice a week in a weight-training class.
Training of the experimental group was designed to
increase muscular strength of the upper and lower extremities.
An inactive control group was used also.
Find-
ings indicated that individual differences in the amount
of change in the strength/mass ratio have a low but
significant correlation with individual changes in maximal
speed of movement.
Gray, Start, and Walsh (20) studied the relationship
between the leg speed and leg power by using a bicycle
ergometer and vertical power testings, in which the subject assumed a full crouch starting position (with one
hand behind his back and the other upstretched by his
head) and sprang upwards and marked the top of his jump
with chalked fingers.
Results showed that leg speed as
measured by the bicycle ergometer and leg power as
23
measured by the vertical power jump correlated +0.470,
which was significant at the .001 level.
To study the individual· differences .in limb speed,
reaction, and strength, Henry (19) used forward and backward arm leg movements.
Eighty subjects first made a
twenty-eight inch overhand throwing movement, first
with the right arm and then with the left.
Then they
made a twenty-eight inch forward leg kick, first with the
right leg, then with the left leg.
trials for each movement.
There were twenty
From the data obtained, the
study concluded that limb strength and limb speed are
unrelated factors.
Hinson and Rosentswieg (25) investigated the comparison of isometric, isotonic, and isokinetic exercises
by electromyography.
Thirteen women performed maximum
contractions of biceps brachii in each of the three
methods of contraction.
Isometric contractions were
executed with the forearm in the supinated position at
140, 120, 90, and 70 degrees of elbow flexion.
Isokinetic
contractions were executed on a Super Mini-Gym by pulling
its cable upward from the floor.
Isotonic contractions
involved a standard dumbbell and weight discs.
Intre-
grated electrymographic data was recorded as a simultaneous film record of each contraction that was made.
An
analysis of variance revealed that isokinetic contractions
24
elicited significantly greater .muscle action potential
than either isotonic or isometric contractions.
No
significant differences were found to exist for the
muscle action potential at various angles of elbow flexion
during the isometric or isokinetic contraction.
Van Oteghen (44) investigated two speeds of isokinetic exercise as related to the vertical jump performance
of women.
Her results showed that the slow and fast
speed isokinetic groups were significantly superior to the
control group on vertical jump performance, and the slow
speed isokinetic group improved significantly more in
strength than did the control group.
Pipes and Wilmore (35) investigated strength increments of two isokinetic programs and one isotonic training program.
Thirty-six male volunteers were placed in
one of four groups:
isokinetic low speed contraction,
isokinetic high speed contraction, isotonic contraction,
and a control group.
E~ch
training group met three days
per week and performed the bench press, biceps curl, leg
press, and bent rowing.
Results show that isokinetic
programs produce greater strength gains than the isotonic
regime, and the high speed isokinetic routine was more
effective than the low speed program.
Thistle (42) conducted a study involving an eight
week exercise period.
Exercise groups consisted of an
~·-
25
isokinetic group and a group using weight lifting methods,
plus a group using isometric contractions.
In total
work ability the isokinetic group improved 35.4 percent,
the weight lifting group 27.5 percent, and the isometric
group 9.2 percent.
Section IV
Relationships of Strength Training
on Specific Sport Activities
Studies presented in this section are based on
research concerning the relationship of strength to
actual athletic performances.
There were no comparisons
of isokinetic programs to actual athletic performance.
SWIMMING
Davis (15) investigated the effects of a weight
training program on speed in swimming the crawl stroke
for distances of twenty-five and fifty yards.
used were:
supine
pres~,
Exercises
single straight arm pull down
with pulley weights, two arm curl with barbell, deep
knee squats with barbell, stiff leg dead left with barbell, supine arm circling with dumbbells, bent over
rowing with barbell, and sit-ups on an inclined board.
Seventeen subjects participated in a weight training
program three times a week for eight weeks.
Significant
~··
~··_.
- ----
-~-·~--.--
26
tmprovement was shown for both. the twenty-five and fifty
yard swims.
BASEBALL
Thompson and Martin (43) studied the effects of
weight training on the throwing speed of college varsity
baseball players.
Electronic measurements were made on
the speed of throwing distance at fifty feet.
A pro-
gressive weight training program was used on the experimental group that consisted of the following:
clean and
press; straight arm pullovers, supine press and alternate
press (alternating each arm in pressing motion).
control group
partic~pated
The
in regular baseball practices.
Increases were shown in throwing speed by the experimental group.
Swangard (41) investigated the effects of isometric
and isotonic exercises on the speed of a baseball throw.
Forty-eight subjects were divided into three groups; two
experimental groups of
and a control group.
~sometric
and isotonic exercises
The isometric group performed five
maximum contractions of six seconds in duration for each
exercise.
The isotonic group executed as many lifts as
possible in thirty seconds, with progressive weight
increases as the number of repetitions increased.
The
throwing speed significantly increased in each of the
"'0<'·
~-
----~---
--·-
--·---
27
three groups, however, the differences between the means
of all groups on all tests were not significant.
McKinney, Logan and Birmingham (30) investigated the
possibility of keeping a baseball_pitcher's arm in
condition to throw hard during the off season.
A four
man high school pitching staff was used and their average
throwing velocity was 87.53 mph.
The program consisted
of pulling the Exer-Genie through a normal throwing range
of motion fifty times per day, five days per week.
to one-half pounds of tension were used.
Two
The workout
was considerably less than what the pitchers had done
during the season.
Accuracy scores indicated slight
improvement on 7,000 pitches.
Summary of Review
In the review of the physiological basis of muscular
strength there is an indication that resistance exercises
should be performed by using multiple joint motion and
explosive repetitions.
It seems apparent that one should
perform repetitions as fast as possible in order to
attain the maximum firing level of muscle fibers.
Train-
ing should be specific to the type of activity one
participates in and to the mechanics of that activity
movement.
_«!!!_'·-· - - -
28
Section II reviewed the body mechanics of kicking.
Section II indicated that no significant increase
in speed of movement is usually attained through strength
training programs.
Some studies show some speed of move-
ment increase, however, not of any statistical significance.
Section IV reviewed studies that examined the effects
of strength training programs on specific sport skill
performance.
While significant increases can occur by
use of weight training
progr~s,
no definite recommenda-
tions of training protocol seemed apparent.
There were
no studies of isokinetic programs in relation to improvement of specific sport skill performances reported in
the literature at this time.
Chapter Three will present the research methods and
design to study the effects of skill-simulated isokinetic
training on the accuracy and velocity of a soccer ball
kicked with the instep drive kick.
-----
"'@)'·
~'·
_____
--
--
CHAPTER III
RESEARCH METHOD AND DESIGN
Procedures
General Design
The purpose of this study was to investigate the
effects of isokinetic training on speed and accuracy of
kicking a soccer ball.
The instep drive kick was used
in this investigation to determine the effects of
isokinetic training on kicking skill.
To determine the effects of isokinetic training
on the instep drive kicking speed and accuracy, a test
for measuring the skill was developed.
A shooting test
was developed to record the velocity of a soccer ball
kicked with the instep drive kick and to record the
accuracy of each kick.
The recording of the velocity
was accomplished by attaching a starter switch to a
digital millisecond timer, which terminated at a target
thirty feet from the ball.
Upon contact with the ball by
the instep drive kick, a starter switch would activate
the timer.
When contact was made between the ball and
target, the timer would stop, recording the elapsed time
in thousandths of a second.
A training program was developed to measure the
improvement of accuracy and velocity by isokinetic
29
30
exercise.
The effects of strength on the speed and
accuracy of the kick were not determined.
The design of
the study included the use of an isokinetic group G ,
1
an isokinetic training and goal shooting group G , and a
2
goal shooting group G .
3
Both the right kicking leg and
left kicking leg were tested within the design of the
study.
The isokinetic group trained with each leg by use
of an isokinetic exerciser (Super Mini-Gym Isokinetic
Exerciser l80X).
Procedures for this group consisted of
three sets of ten repetitions with a minute rest between
each set.
Each leg was employed for a similar set of ten
repetitions.
The isokinetic training and shooting group procedures
consisted of three sets of ten repetitions with a minute
rest between each set, and a shooting accuracy program of
ten shots at the target after each isokinetic training
session.
Each leg was employed for the training and
shooting procedures.
The shooting for accuracy group performed ten shots
each training session to develop speed and accuracy within their training session.
Shooting tests were given to
each group to determine the velocity and accuracy of the
kicked ball.
Each leg was employed for the training and
shooting procedures.
31
Se1ect~on
and Orientation of Subjects
Subjects for this study were thirty-six male volunteers who were individuals attending Los Angeles Baptist
College in Newhall, California.
Their ages ranged from
eighteen to twenty-one years of age.
Subjects were
placed in one of the following three groups based on
matched groupings of Z scores; isokinetic group (G ),
1
isokinetic and goal shooting group (G ), and goal shooting
2
group (G ).
3
Each subject was oriented to the testing procedure
and the nature of the study before actual testing began.
The orientation was approximately one week in advance of
the study.
Pilot Study
A pilot study was conducted in order to test the
isokinetic equipment, the shooting procedures, and timing
equipment.
Within this pilot study eight subjects were
tested using the isokinetic and shooting procedures.
The
study lasted for four weeks.
The shooting distance was determined within this
pilot study.
A distance of thirty feet was selected in
order to allow each subject to use maximum force in
striking the ball and still have control of accuracy
in their kicking.
This distance allowed for a
~·-
32
consistent testing of accuracy without any decrease in the
maximum effort to kick the ball.
To insure a consistent placement of the supporting
leg in the subjects' approach to kick the ball, it was
determined that a one step approach would be most appropriate.
The switches, target components, and isokinetic equipment were found to operate consistently and accurately.
Equipment
A target was constructed that consisted of a green
colored canvas stretched between a wooden structure of
two by four inch wood.
Dimensions of the target are
shown in Diagram I and Illustrations I and II.
patterns are shown in Diagram I.
Scoring
The stretching of the
canvas was accomplished by attaching quarter inch ropes
vertically and horizontally between the wood frame and
the canvas.
Spacing of the ropes formed a netting
pattern of three inch'squares.
This insured uniform
contact of canvas and netting when struck by the ball.
It was positioned in a direct line thirty feet away from
the shooting spot.
The frame was constructed and situated
so that all points of possible contact were an equal distance from the point from which the ball would be kicked.
~··
33
Tension on the ropes was maintained by small two inch
coiled springs attached at each end.
Nine microswitches
were evenly spaced, with three on each vertical post
and three on the bottom horizontal post.
Attached to each
switch was an activating wire, that was stretched directly to the switch positioned across from it on the opposite
post.
The vertical activating wires were attached to the
top postwbich had no microswitches attached to it, because the height of the target didn't allow for quick reactivation of switches.
Upon contact by the ball a
switch was activated and it automatically turned the digital· millisecond timer off.
Alligator clips were fashioned to each end of t·he
activating wires and attached to each microswitch.
Each
wire maintained tight tension between microswitches so
that the least amount of contact by the ball would activate the switches.
A twenty-seven inch diameter leather soccer ball
that was inflated to nine pounds per square inch pressure
was placed on a designated spot on a kicking platform
thirty feet from the target.
procedure.
Illustration III shows this
A microswitch was positioned on the platform
in front of the ball.
The ball was placed directly
against the switch so that when the ball was struck it
would automatically activate the digital millisecond
34
timer, as shown in Illustration IV.
The timer would
record the elapsed time it took the ball to contact the
target after being kicked.
I
- ---I -.. 1
1~
I
f
I
'
_,
I
_t_
I
i
I
J
I
i
I
I
I
1-
'/'
I
!-
·t I
I
-l - 1I
I
-
-
J
f-
'
-}
I
I
I
I
I
II
-
H<6"
I
J\
.
I
'-.
I
I
-
I
l
+ l-1
~I -I
I
-:-
I
I
I
H<~f-,~:r
JJ},
Diagram I.
:
-
L !- ~ I - -I -I: i T ~~ --Jr-1 -+ r '- - +
I
'
:
i
,1£_/;j -3 t; -- #'f. I
-I_
--.-
!;Jj
-
!
~_rl-t
.- -
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i
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V-2._
l
i
/
1
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r
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t
':l/l
H
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·' ,• •
.·-}
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35
Illustration I.
Illustration II.
~_:;
__
~··
36
Illustration III.
Illustration IV.
37
A Super Mini-Gym Isokinetic Exerciser 180X was used
as the isokinetic exercising device within the study.
Illustration V illustrates this device.
Illustration V.
A stabilizing pole measuring four feet high was used
when exercising with the isokinetic device, in order to
allow for stabilization of the non-kicking leg.
This
allowed for a maximum kicking force by the leg being
exercised.
Illustration VI illustrates this device.
A stirrup was attached to each subjects kicking
foot and directly connected to the isokinetic device by
means of a nylon rope.
This placed the foot in a
'~··
38
position of plantar flexion, which is more specific to
the instep drive kick.
It also allowed involvement of the
knee extensor muscles which would contribute to kicking
speed.
Illustration VI illustrates this device.
Illustration VI.
Shooting Tests
Shooting measurements were recorded at the beginning,
middle, and end of testing procedures, to gauge progress
of subjects.
In these shooting tests, both speed and
accuracy were recorded.
Each test was measured from the
designated kicking spot of thirty feet from the target.
The ball was placed directly against the switch so
that when the ball was struck it would automatically
~'·
39
activate the digital millisecond timer.
The timer
recorded the elapsed time it took the ball to contact
the target after it was kicked.
With the accuracy test
the timers were not activated.
In the shooting test, each subject shot at the target
-three times with the right foot and then three times with
the left foot.
The slowest and fastest elapsed time of
the three kicks was discarded, to allow for any error
factor or inconsistency of testing or testing devices.
In the accuracy shooting test, each subject shot at
the target a total of ten times with the right foot and
then ten times with the left foot.
Scores were recorded
according to the area of the target they contacted and
totaled.
If a subject hit a line of the target the lower
score was recorded.
The shooting tests for accuracy and speed were
performed independently in order that fatigue would not
effect the performance due to the length of accuracy
testing.
Strength Tests
Strength recordings were taken from the read-out of
the dial recording of the isokinetic device, however,
they were not used in a statistical recording, because of
the wide ranges of inaccuracy of the recording dial.
40
The recording dial could not show smaller units of
measurements, because of the gross divisions on the face
of the isokinetic device.
Also there was no way of deter-
mining the pounds of pull from the recording dial.
Recordings were made by having each subject perform
through a normal range of movement for a kicking action,
while attached to the
iso~inetic
device.
A maximum
force of kicking action was performed three times.
leg was tested separately.
Each
A stabilizing pole was used
in order to allow for stabilization of the non-kicking
leg and to allow for a more exact maximum kicking force
by the
kickin~
leg.
Training Program
The isokinetic group G performed three sets of ten
1
repetitions with each leg, three times a week.
minute:of rest was taken between each set.
One
While per-
forming each set, the subject used.a stabilizing pole
position next to and in' front of the non-kicking leg or
support leg.
This allowed for a more exact maximum
kicking force by the kicking leg.
Each subject was ob-
served in order to ensure he performed ten consecutive
and maximum repetitions.
The isokinetic and goal shooting group G performed
2
the same exercise routine, plus shooting ten shots at the
41
target for accuracy.
In shooting at the target each sub-
ject was observed to ensure that while shooting at the
target he gave maximum effort in his shooting speed.
No
recordings of accuracy were taken during training periods.
Immediate feedback of accuracy was available for every
subject on every kicked ball.
The goal shooting group G shot at the target ten
3
times with each foot.
Each subject was observed to ensure
that maximum effort was given while shooting for accuracy.
No recordings of accuracy were taken during the training
period.
Immediate feedback of accuracy was available for
every subject on every kicked ball.
In all shooting routines the subject was allowed to
take only one step and instructed to place the non-kicking
foot alongside the ball.
An instep drive kick ,would then
be performed.
All recordings of data were collected during a sixweek training period.
Monday, Wednesday, and Friday were
designated as training days.
~-··
9$1'·
Chapter IV
FINDINGS AND INTERPRETATION OF THE DATA
This study was conducted to determine the effects of
skill-s:imula ted isokinet ic training on the accuracy and
velocity of a soccer ball kicked with the instep drive
kick.
Thirty-six college soccer players were tested in
this study.
Three groups of twelve players were formed
out of the thirty-six subjects; isokinetic group G ,
1
isokinetic and goal shooting group G , and goal shooting
2
group G .
3
The isokinetic group trained with each leg
doing three sets of ten repetitions with a minute of rest
between each set, while using an isokinetic exerciser
(Super Mini-Gym Isokinetic Exerciser 180X).
The isokine-
tic training and goal shooting group procedures consisted
of three sets of ten repetitions with a minute of rest
between each set while using an isokinetic exerciser and
a goal shooting program. of ten shots at the target after
each isokinetic training session.
The goal shooting group
performed ten shots each training session with each leg.
All data was collected over a six-week testing period.
Test data was collected at the beginning, middle, and
end of the study.
Subjects were assigned to one of the
above groups on the basis of Z scores achieved on the
pre-test.
It was necessary to determine the performance
42
~···
43
equality of the three groups with respect to soccer
kicking ability.
Subjects were matched between the
following groups; isokinetic group G1 , isokinetic and
goal shooting group G , and goal shooting group G by
2
3
ABC, CBA, BCA, etcetera method, so that each subject had
close to identical twins in the opposite groups, based
upon pre-test scores for accuracy and speed.
All results
were analyzed statistically by determining the significance of the difference between mean gains.
The levels of confidence of ,. 05 and . 01 were adopted
as the base for accepting or rejecting the hypothesis.
The hypothesis tested was:
that there would be signifi-
cant differences in skill-simulated isokinetic training
on the accuracy and velocity of a soccer ball kicked with
the instep drive kick.
The purpose of this chapter is to
present an analysis of the data collected.
The data of the study were analyzed to determine:
1) whether the soccer kicking test for speed and accuracy
designed for this study was a reliable measure of accuracy
and kicking ability, 2) whether the groups were equal in
speed and accuracy at the onset of the study, and 3)
whether significant differences occurred within or between
the experimental groups as a result of the imposed experimental variables.
44
Reliability of the Soccer
K~cking
Tests
The reliability of the two soccer kicking tests for
speed and accuracy were determined from data collected
during a preliminary investigation.
By using test-retest
scoring procedures on eight subjects, the reliability of
tests on speed and accuracy was determined.
Speed was
tested by having each subject kick a soccer ball at a
scoring target, which was attached to a millisecond timer
which terminated at the target thirty feet from the ball.
Data was collected for both kicking legs.
Accuracy was
determined by having each subject kickten times, with
both kicking legs, and generating a total kicking accuracy
score.
Two consecutive days were used for test-retest
scoring.
The reliability of the kicking speed at the scoring
target proved to be .880 for the left leg and .810 for the
right leg.
An r of .666 was required for the five percent
level of confidence and an r of .798 was required for
significance at the one percent level of confidence.
(45)
The reliability of the accuracy scoring on the target
proved to be .800 for the left leg and .896 for the right
leg.
An r of .666 was required for the five percent level
of confidence and an r of .798 was required for significance at the one percent level of confidence.
appears in Table I. (45)
The data
~··
45
Table I
Test-Retest Reliability for
Speed and Accuracy on
Soccer Kicking
Significance of Difference Between Groups
Performance equality of the three groups with respect
to soccer kicking ability of speed and accuracy was determined after assigning the subjects to one of the three
experimental groups on the basis of Z scores achieved on
the pre-test.
Table 2 shows the equality of the three
groups on speed and accuracy.
46
Table 2.
A Comparison of the Three Experimental
Groups on the Pre-Test
Group:
Accuracy
Mean Score -
Standard Deviation
Right Leg
A.
4.42
15.91
4.59
15.75
G3 (Shooting)
Left Leg
4.46
15.91
A.
4.42
15.75
4.31
15.66
4.86
15.00
G1 (Isokinetic)
B. G (!so-Shooting)
2
C. G (Shooting)
3
Left Leg
.483
.392
.499
.333
.449
.314
A.
.530
.403
B.
G1 (Isokinetic)
G2 (!so-Shooting)
.547
.400
C.
G3 (Shooting)
.537
.411
B.
G (Isokinetic)
1
G2 (!so-Shooting)
C.
B.
G (Isokinetic)
1
G2 (!so-Shooting)
C.
G (Shooting)
3
Group: Speed
Right Leg
A.
Table 2 shows that the means and standard deviations
of the three groups, when compared with one another and
47
each kicking leg, were very similar.
(14),
groups~
According to Clarke
which have similar measures of central
tendency and a similar scatter of scores about the mean,
can be accepted as being equated.
Results of a t test, were used to determine if significant differences existed between the groups after the
pre-test.
Results are shown in Table 3.
Table 3
Significance of Difference Between the Three
Experimental Groups on the Pre-Test,
Using Mean Scores
for Accuracy
Group:
Right
Mean
-
Group
G1
15.91
G2
G2
15.75
G1
Diff.
t
15.75
.16
.07
G3
15.91
.16
.07
15.91
G3
15.91
.00
.00
G1
15.75
G2
15.66
.09
.04
G2
15.66
G3
15.00
.66
.39
G1
15.75
G3
15.00
.75
.35
Grou12:
Note:
Mean
Left
None of the groups were significantly different
from any of the other groups.
No difference between groups yielded a t score near
the required 2.20 for significance of difference at even
48
the five percent level of confidence.
(12)
It was
concluded that there were no significant differences
between the groups on the basis of scores made on the pretest for accuracy.
The accuracy scores of the experimental groups were
then examined for differences between the groups after
the mid-test.
The data are presented in Table 4.
Table 4
Significance of Difference Between the Three
Experimental Groups on the Mid-Test,
Using Mean Scores
for Accuracy
Group:
Right
Mean
-
Group
Mean
Diff.
t
G1
17.08
G2
17.83
.75
.45
G2
17.83
G3
18.83
1.00
.15
G1
17.08
G3
18.83
1.75
.68
G1
13.58
G2
17.58
4.00
2.68*
G2
17.58
G3
14.91
2.67
1.57
G1
13.58
G3
14.91
1.33
.61
Group:
Left
*Significant at the five percent level of confidence
Table 4 show that G improved from the pre-test on
1
the right foot, but declined with the left foot.
G
2
49
'
improved on both the right and left foot from the pretest.
G improved from the pre-test on the right foot,
3
but declined slightly with the left foot.
While there
were no significant differences between G and G , or
2
3
between G and G , the difference in mean scores between
1
3
G and G resulted in a ! score of 2.68, which was signi2
1
ficant at the five percent level of confidence.
(12)
The accuracy scores of the experimental groups were
then examined for differences between the groups after
the post-test.
The data are presented in Table 5.
Table 5
Significance of Difference Between the Three
Experimental Groups on the Post-Test,
Using Mean Scores
for Accuracy
Groun:
Right
Mean
Grou2
Mean
Diff.
t
18.58
1.33
.79'.
18.66
.08
.04
G1
17.25
G2
18.58
G1
17.25
G3
18.66
1.41
.70
G1
15.83
G2
17.75
.97
.97
G2
17.75
G3
15.42
1.45
1.45
G1
15.83
G3
15.42
.25
.25
Group:
Note:
G2
"G
3
Left
None of the groups were significantly different
from any of the other groups.
'
50
Table 5 shows that G , for both right and left legs,
1
improved from the mid-test and completed the study with a
mean score of 17.25 and 15.83.
G also _improved for both
2
legs and concluded the study with a mean score of 18.58
and 17.75.
G , however, was slightly lower from the mid3
test on the right let and finished with a mean score of
18.66.
The left leg improved and finished with a mean
score of 15.42.
It was concluded that there were no
significance differences between the groups formed on the
basis of scores made on the post-test for accuracy.
The speed scores of the experimental groups were then
examined for differences between the groups after the pretest.
The data are presented in Table 6.
51
Table 6
Significance of Differences Between the Three
Experimental Groups on the Pre-Test,
Using Mean Scores
for Speed
Group:
Right
Mean
-
Group
Mean
Diff.
t
Gl
.483
G2
.499
.016
.44
G2
.499
G3
.449
.050
1.76
Gl
.483
G3
.449
.034
1.09
Gl
.538
G2
.547
.009
.21
G2
. 547
G3
.537
.010
.38
Gl
.538
G3
.547
.001
.03
Group:
Note:
Left
None of the groups were significantly different
from any of the other groups.
No differences between groups yielded a t score near
the required 2.20 for significance of difference at even
the five percent level of confidence.
(12)
It was con-
eluded that there were no significant differences between
the groups formed on the basis of scores made on the pretest for speed.
The speed scores of the experimental groups were then
examined for differences between the groups after the midtest.
The data are presented in Table 7.
52
Table 7
Significance of Difference Between the Three
Experimental Groups on the Mid-Test,
Using Mean Scores
for Speed
Group:
Mean
-
Group
Mean
Diff.
G1
.481
G2
.512
.031
1.03
G2
.512
G3
.466
.046
1.36
G1
.481
G3
.466
.015
.41
G1
.517
G2
.580
.063
1.75
G2
.580
G3
.531
.049
1.32
G1
.517
G3
.531
.014
.50
Group:
Note:
Right
t
Left
None of the groups were significantly different
from any of the other groups.
Table 7 shows that G improved from the pre-test on
1
both the right and left feet.
G , however, declined on
2
both the right and left feet from the pre-test.
G3
improved from the pre-test on both right and left feet.
It was concluded that there were no significant differences between the groups formed on the basis of scores
made on the mid-test for speed.
The speed scores of the experimental groups were then
examined for differences between the groups after the
~··
~··
53
post-test.
The data are presented in Table 8.
Table I
Significance of Difference Between the Three
Experimental Groups on the Post-Test,
Using Mean Scores
for Speed
Group:
Mean
Group
Mean
Diff.
t
G1
.482
G2
.496
.014
.39
G2
.496
G3
.466
.030
.96
G1
.482
G3
.. 466
.016
.26
G1
.512
G2
.543
.031
.83
G2
.543
G3
..522
.021
.80
G1
.512
G3
.522
.010
.32
Group:
Note:
Right
Left
None of the groups were significantly different
.from any of the other groups.
Table 8 shows that G improved from the mid-test on
1
the left foot and declined slightly on the right foot.
It
concluded the study with a mean score of .512 and .482 for
both feet.
G improved for both feet from the mid-test
2
and completed the study with a mean of .496 and .543 for
right and left feet.
G stayed the same on the post-test
3
score for the right foot and improved on the left foot
from the mid-test score.
It completed the study with
54
means of .466 and .522 for right and left feet.
It was
determined that there were no significant differences between the groups formed on the basis of scores made on the
post-test for speed.
Significance of Difference Within Groups
In addition to determining the differences between
the experimental groups, the differences within the groups
were also calculated.
Table 9 shows the results of the
t tests which were used to determine if significant differences existed within experimental groups.
Table 9
shows differences within each group for-the accuracy test.
~·-
55
Table 9
The Significance of Difference Within the
Experimental Groups Between the Pre-Test,
and Post-Test, Using Mean Scores
for Accuracy
Group:
Pre-Test
Post-Test
Diff.
G1
15.91
17.25
1.34
2.31*
G2
15.75
18.58
2.83
3.98**
G3
15.91
18.66
2.75
2.83*
G1
15.75
16.16
.41
1.03
G2
15.66
17.75
2.09
.71
G3
15.00
15.42
.42
.62
Group:
Right
t
Left
*Significant at the five percent level of confidence
**Significant at the one percent level of confidence
Table 9 shows that the right foot performed better
than the left foot in·terms of mean differences.
Dif-
ferences in pre-test and post-test scores for G and G
3
1
yielded a ! score beyond the required 2.20 for significance of difference at the five percent level of confidence.
G yielded a ! score beyond the required 3.11 for
2
significance of difference at the one percent level of
confidence.
It was concluded that there was a significant
~-··
56
difference between the formed groups on the basis of
accuracy scores made on the pre-test and post-test scores
of the right foot, but not for the left foot.
The speed scores of the experimental groups were then
examined for differences within the groups based on pretest and post-test scores.
Table 10 shows differences
within groups for the speed test.
Table 10
The Significance of Differences Within the
Experimental Groups Between the Pre-Test,
and Post-Test, Using Mean Scores
for Speed
GrouE:
Ri~ht
Pre-Test
Post-Test
Diff.
t
G1
.483
.476
.007
.48
G2
.499
.496
.003
.29
G3
.449
.466
-.017
-.81
G1
. 538"'
.512
.026
1.07
G2
.547
.543
.004
.34
G3
.537
.522
.015
.88
Group:
Note:
Left
None of the groups showed significant differences
Table 10 shows that all groups improved in size of
mean differences, except G , which declined.
3
No
57
differences in pre-test and post-test scores yielded a
!
score beyond the required 2.20 for significance of difference at the five percent level of confidence.
It was
concluded that there were no significant differences
between the scores formed on the basis of speed scores
made on the pre-test and post-test scores.
SUMMARY OF FINDINGS
1.
No significant differences between the groups
were found on the basis of scores made on the
pre-test for accuracy.
2.
Significant differences between groups were
found for the left foot of mid-test scores
between Isokinetic and Iso-Shooting groups at
the five percent level of confidence.
No other
groups showed significant differences on the midtest scores for accuracy.
3.
No significant.differences between the groups
were found on the basis of scores made on the
post-test for accuracy.
4.
No significant differences between the groups
were found on the basis of scores made on the
pre-test, mid-test, and post-test scores for
speed.
5.
Significant differences within groups were
58
found for the right foot of pre-test and posttest, using mean scores for accuracy.
The !so-
kinetic and Shooting groups were significant at
the five percent level of confidence and the !soShooting group at the one percent level of confidence.
6.
No significant differences within groups using
mean scores for speed were found on the basis
of scores between the pre-test and post-test
scores for speed.
CHAPTER V
SUMMARY, FINDINGS AND RECOMMENDATIONS
Summary
Soccer is a sport not only of strength and endurance,
but of skill in body movements.
Development of proper
training techniques contribute to the acquisition of
skills involved in the sport.
Investigation of training
techniques is a major concern of soccer coaches who wish
to develop more skillful players.
With the increase of
soccer competition, every investigation can make a
critical contribution to solving the problem of efficient
use of time.
A review of the literature revealed a need to devise
training programs which develop specific muscle groups
for specific activities.
This investigation involved an
examination of a specific skill in which resistance to the
muscles involved was applied throughout the range of
motion with the specific velocity simulating the activity
as nearly as possible.
It was anticipated that valuable
information needed for developing training techniques
for the instep drive kick in soccer would result from the
findings.
Thirty-six subjects participated in a six week
training program conducted three times per week to
59
,., ..
60
determine the effects of isokinetic training on the
velocity and accuracy of a soccer ball kicked with the
in~tep
drive kick using either foot.
The subjects were
assigned to three groups consisting of an isokinetic group
G , an isokinetic and goal shooting group G , and a goal
2
1
shooting group G .
3
Placement of subjects was based on
matched groupings of Z scores in pre-testing.
All the groups were evaluated in a pre-test to measure the velocity of a ball traveling from a given point
to a target thirty feet away.
at that distance.
Accuracy was also measured
A mid-test and post-test for time and
accuracy were also administered.
The isokinetic group G trained with each leg, doing
1
three sets of ten repetitions, while using an isokinetic
exerciser.
The isokinetic and goal shooting group G ,
2
doing three sets of ten repetitions, also trained with
each leg on the isokinetic exerciser, and took ten shots
at a target thirty feet away, after each isokinetic
training session.
The goal shooting group G performed
3
ten shots at the target with a soccer ball over a distance
of thirty feet from a designated kicking spot.
Findings
On the basis of this study, the following findings
were made.
61
1.
Significant differences at the 0.5 level of
confidence were found for the left foot of
mid-test scores for isokinetic
and isokinetic
goal shooting groups for accuracy.
No other
groups showed significant differences on the
mid-test or post-test scores.
2.
No significant differences between the groups
were found on the basis of scores made on the
pre-test, mid-test, and post-test scores for
speed.
Scores did show improvement when pre-
test scores were compared to post-test scores,
but the differences were not significant.
3.
Significant differences within groups were
found for the right foot of pre-test and posttest, using mean scores for accuracy.· The isokinetic group and goal shooting group were significant at the 0.5 level of confidence.
kinetic and
go~l
shoot~ng
The iso-
group was significant
at the 0.1 level of confidence.
4.
No significant differences within groups were
found on the basis of scores made between pretest scores and post-test scores for speed.
The scores did show improvement, however, the
difference was not significant.
~'·
62
Conclusion
. The hypothesis that isokinetic training would have
an effect on either the velocity or accuracy of a soccer
ball kicked with the instep drive kick, was accepted with
the right foot at the 0.5 and 0.1 levels of confidence for
accuracy.
The isokinetic group G and the goal shooting
1
group G were significant at the 0.5 level of confidence
3
in pre-test/post-test analysis within groups.
The isokine-
tic and goal shooting group G2 were significant at the 0.1
level of confidence in pre-testjpost-test analysis within
groups.
The pre-testjpost-test analysis of the right foot
for velocity showed improvement, but was not significant
at an acceptable level of confidence within groups.
The pre-testjpost-test analysis of the left foot for
velocity or accuracy showed improvement, but was not significant at an acceptable level of confidence within groups.
The hypothesis was rejected for all other tests
between groups with regara to velocity and accuracy using
either foot.
Slight improvement was shown, but not of an
acceptable level of confidence.
In conclusion, the above findings suggest that isokinetic training is most valuable when one spends time
working with an isokinetic training device (in a skillsimulated program) and also performing actual skill within
63
training time.
Findings also suggest that isokinetic
training can be of value when training in a skill-simulated
program alone.
Recommendations For Further Investigation
On the basis of the findings of the study, it is
recommended that:
1.
Strength gains should be investigated to
determine if strength is improved when using
isokinetic training devices (when associated
with velocity and accuracy of kicking a soccer
ball).
2.
Future studies investigate isokinetic training
when speed and accuracy are scored simultaneously
in kicking a soccer ball at a target.
3.
A future study should investigate isokinetic
training (when associated with velocity and
accuracy of
kic~ing
a soccer·ball) as compared
to the use of variable resistance weight lifting
machines, hydraulic weight lifting machines, and
chain or cam device weight lifting machines.
4.
The study be repeated using highly skilled
performers or lower skilled performers.
~l
'
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64
65
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