The Effect of Dynamic and Static Stretching on
Performance
A THESIS
Submitted to the Faculty of the School of Graduate
Studies and Research
of California University of Pennsylvania in partial
fulfillment of the requirements for the degree of
Master of Science
by
Jaclyn C. Oakley
Research Adviser, Dr. Ben Reuter
California, Pennsylvania
2007
ii
iii
ACKNOWLEDGEMENTS
I would like to take this opportunity to thank the
many people who made this thesis a success.
First and
foremost, I would like to thank my parents for always
believing in me and encouraging me to strive to reach my
goals.
Without their unconditional love and support, I
would not be where I am today.
I also want to thank my
sisters for being my best friends; Jill for being like a
second mother to me, Jen for all the laughs and memories,
and Jess, the best listener I know.
I also want to thank
my fifth sister, Lauren, who has been my best friend
since the second grade.
She has been there for me
through the good times and the bad, and I am so lucky to
have her in my life.
Next I would like to thank my committee members Dr.
Reuter, Dr. Hess, and Dr. Kinsey, for all of their help
this year.
I want to especially thank Dr. Reuter for
pushing me to excel in every aspect of this thesis.
Without his knowledge and high expectations, this would
not have been possible.
I would also like to thank Dr.
Hess for her dedication and encouragement, and Dr. Kinsey
for his statistical expertise.
iv
A huge thank you also goes out to Mark and Mike
Lesako, who are two of the most amazing people I have
ever met.
They helped me in every way with the
organization of this study, making it as easy as possible
for me to carry out.
I am incredibly lucky to have
gotten the chance to work along side them at W&J, and owe
them so much for so many reasons.
Mike and Mark; I had a
blast with you this year, and I hope our friendship
continues for years to come.
Lastly, I would like to thank the other graduate
students as well as the underclassmen who have become
like a family to me this year.
From the time we all met
back in the summer, we grew so close, and I would never
have made it through this year without their support.
Phylissa, you have been a great friend to me throughout
our four years at King’s, and I am so glad we could
continue our education together for graduate school.
I
know you will excel in your Doctorate program, and will
miss you so much.
Aimee, you have been there for me in
every way possible this year, and I value our friendship
so much.
Mitch, thank you for generously sacrificing
your time to help me when I was in need.
To all my
classmates; thanks for all the memories, and for making
this year such a great one.
v
TABLE OF CONTENTS
Page
SIGNATURE PAGE . . . . . . . . . . . . . .
ii
ACKNOWLEDGEMENTS . . . . . . . . . . . . . iii
TABLE OF CONTENTS . . . . . . . . . . . . .
v
LIST OF TABLES . . . . . . . . . . . . . .
vii
LIST OF FIGURES . . . . . . . . . . . . . . . . . viii
INTRODUCTION . . . . . . . . . . . . . . . .
METHODS
1
. . . . . . . . . . . . . . . . . 6
Research Design. . . . . . . . . . . . . . 6
Subjects. . . . . . . . . . . . . . . . . . 7
Instrumentation
. . . . . . . . . . . . . 7
Procedures
. . . . . . . . . . . . . . . . .9
Hypotheses
. . . . . . . . . . . . . . . 12
Data Analysis
. . . . . . . . . . . . . . 12
RESULTS . . . . . . . . . . . . . . . . . . 13
Hypotheses Testing
DISCUSSION
. . . . . . . . . . . . 13
. . . . . . . . . . . . . . . . 17
Discussion of Results . . . . . . . . . . . 18
Conclusions . . . . . . . . . . . . . . . 21
Recommendations . . . . . . . . . .
REFERENCES
. .
. . . . .
22
. . . . . . . . . . . . . . 24
APPENDICES . . . . . . . . . . . . . . . . . . . . . 27
A. Review of the Literature . . . . . . . . . . . 28
vi
Stretching and Flexibility .
. . . . . . . 29
Mechanisms of Stretching . . . . . . . . . . 29
Stretching Techniques . . . . . . . . . . .
31
Stretching and Power . . . . . . . . . . . . . 34
Stretching and Performance . . . . . . . . . . 36
Stretching and Injury Risk . . . . . . . . . . 41
Summary . . . . . . . . . . . . . . . . 43
B. The Problem . . . . . . . . . . . . . . 47
Statement of the Problem . . . . . . . . . 47
Definition of Terms . . . . . . . . . . . 48
Basic Assumptions . . . . . . . . . . . . 50
Limitations of the Study . . . . . . . . . 51
Significance of the Study
. . . . . . . . 51
C. Additional Methods. . . . . . . . . . . . 54
Informed Consent (C1) . . . . . . . . . . .55
Functional Testing and Equipment (C2) . . . .
59
Stretching Protocols (C3) . . . . . . . . . .
62
Institutional Review Board (C4) . . . . . . .67
Athletic Director Consent Form (C5) . . . . .
74
Data Collection Sheets (C6). . . . . . . . . . 76
REFERENCES
ABSTRACT
. . . . . . . . . . . . . . . 79
. . . . . . . . . . . . . . . . 83
vii
LIST OF TABLES
1. 2 X 3 repeated measures ANOVA for test (2)
by condition (3) for effect of stretching
conditions on the T-test for agility. The type
of stretching condition had a significant
effect (.008) . . . . . . . . . . . . . . . . . .
15
2. Means and Standard Deviations for the T-test
For agility times according to the stretching
Condition . . . . . . . . . . . . . . . . . . . .
16
3. Paired t-test for the means and standard
deviations for static stretching and dynamic
stretching (Pair 1), dynamic stretching and the
control Pair 2), and static stretching and the
control (Pair 3) . . . . . . . . . . . . . . . . . 16
4. Paired t-test for the differences between
Static for static stretching and dynamic
stretching (Pair 1), dynamic stretching and the
control Pair 2), and static stretching and the
control (Pair 3) . . . . . . . . . . . . . . . . . 16
viii
LIST OF FIGURES
1. Mean T-test for agility times of the
Stretching conditions(3) with the interaction
Of tests(2) . . . . . . . . . . . . . . . . . . . . 17
INTRODUCTION
Stretching and flexibility training have been very
common among the athletic population, making up a large
part of training programs as well as pre-event warm-up
activities for athletes.1-15
Flexibility refers to the
musculotendinous unit’s ability to elongate with the
application of a stretching force, determining the range
of motion of a joint.1,2
Therefore, the act of stretching
can be defined as movement applied by an external or
internal force in order to increase muscle flexibility
and/or joint range of motion.3
It has been theorized by athletes, coaches, and
athletic trainers that increasing flexibility is an
important aspect of physical fitness, leading to an
increase in athletic performance as well as reducing the
incidence of injury.3,13,14,16,17-19,22
However, recent
research has found that the acute effects of stretching
may have negative results on both performance and risk of
injury.2-19 Studies have shown that static stretching
before competition may lead to musculoskeletal injury
rather than preventing injuries from occurring.
The
result of increased flexibility due to stretching may be
attributed to a decrease in joint stability making
2
athletes more prone to injury.8,18 In addition to this
increased risk of injury, it has also been found that
stretching before participation may cause a decrease in
muscle strength, power output, and sprint
performance.3,8,13
In relation to strength and power, results in a
study by Papadopoulos et al20 examined the effects of
static and dynamic stretching on strength.
The static
stretching consisted of an active hamstring stretch and
an active quadriceps stretch on the test leg each held
for 30s.
Torque (the ability of a force to cause
movement) was used as a measure of strength, and results
showed a significant difference following the two
different stretching techniques.1,20
Torque was
significantly reduced with the static stretching
exercises, while no effect was seen when preceded with
the dynamic stretching exercises.20
A similar study by
Fowles et al6 found that when looking at the torque of
the plantar flexor muscles, the strength was reduced by
30% immediately after a static stretching regimen.
Torque was still reduced by nine percent 60 minutes after
the stretching took place. This length of time shows that
pre-exercise stretching negatively affects peak torque up
to at least 60 minutes.
Nelson et al17 also reported that
3
when knee flexion lift exercises were performed (in which
the knee is flexed in a prone position) at 60% or 40% of
body weight, static stretching significantly reduced
strength.
These studies are all in agreement with one
another indicating that static stretching negatively
affects strength production.
The recent literature concerning static stretching
has reported a negative effect on sport performance.
This is a growing concern among sports professionals,
encouraging them to learn more about the most effective
warm-up methods to positively benefit performance.
The
results in many of these studies have been dynamic
stretching.
In a study by Fletcher8 comparing the effect of
static and dynamic stretch protocols on a 20 meter sprint
performance, it was found that the groups participating
in the static stretching warm-up had a significant
increase in their sprint time, and the dynamic stretching
groups had a significant decrease in their sprint times.8
Similarly, in a study by Siatras et al21 examining
gymnasts’ vaulting speeds, it was found that vault speeds
were significantly decreased following static stretching
exercises.
4
In contrast, Little and Williams22 found static
stretching not to be detrimental to high speed
performance including vertical jump, 10m sprint, 20m
sprint, and a zig-zag agility test.
However, dynamic
stretching was found to be the most effective as a warmup for performance producing significantly faster sprint
times.
Dynamic stretching was also found to be the most
effective stretching technique in a study by McMillian et
al,9 revealing better performance scores in the T-shuttle
run, medicine ball throw, and the 5-step jump as compared
to static stretching and no stretching.
In two very similar studies looking at adolescents,
both conducted by Faigenbaum et al,
(10,11)
results showed
that pre-event dynamic stretching alone or in conjunction
with static stretching is more beneficial than static
stretching alone.
However, it is important to realize
that the subjects used in these studies were adolescents,
which could produce different results when compared to
adults, due to the fact that adolescents are still
growing.
Although there is still some contradictory evidence
regarding static and dynamic stretching, the majority of
recent literature indicates that static stretching may be
detrimental to an athlete’s performance.
These studies
5
seem to be in favor of dynamic stretching, which has
shown to be much more beneficial.2-19
Results have led to
a great deal of interest from the athletic professionals,
who are beginning to move away from the traditional
method of static stretching, and incorporate dynamic
stretching into their warm-up routines.8-10,22
This study will attempt to answer the following question:
1)How do the treatments of dynamic stretching, static
stretching, and no stretching affect the performance on
the T-test for agility?
6
METHODS
The methods section will serve to give an overview
as to how the experiment was conducted.
It will include
sections dedicated to Research Design, Subjects,
Instrumentation, Procedures, Hypotheses, and Data
Analysis.
Research Design
A quasi-experimental design, in which the subjects
were each serving as their own control, was used for this
study.
All subjects were volunteers; and were not
randomly selected.
The independent variable was the
stretching protocol used (dynamic stretching warm-up
protocol, static stretching warm-up protocol, and no
stretching).
The dependent variable was the time on the
T-test for agility.
The strengths of the study were that
the population was already known (Division III football
players) and a sample was taken from that particular
population.
In addition, the study is a within subjects
design in which each subject served as their own control.
Limitations of this study are that the results can only
be generalized to Division III football players, the
subjects were volunteers, and that the same person served
7
as the researcher, the data collector and the Athletic
Trainer.
Subjects
The subjects in this study consisted of 18 male
Division III football players (n=18).
All subjects were
between the ages of 18 and 23 years, and had not
sustained a lower extremity injury within the past six
months. The volunteers were chosen by a sample of
convenience, with no influence from the coaching staff.
The subjects were screened for previous history of lower
extremity injuries, and those who have had these injuries
in the past six months were excluded from volunteering.
Each subject completed an Informed Consent (Appendix C1)
before participating in the study. No names were included
in the study.
Instrumentation
The testing instruments that were used in this study
were the T-test for agility, and the Speed Trap II timing
system.
The Speed Trap II TimerTM (Appendix C2) is a
timing system that starts timing when pressure is
released from the starting pad, and stops when the
8
athlete crosses the reflective beam at the finish line.
The times are recorded on the clock that sits on top of
the beam.23 This timing system is accurate to 1/100th of a
second, and is capable of timing an athlete up to 55
yards accurately.
23
This piece of equipment was used to
measure the velocity of the athletes’ T-test for agility,
testing agility.
The T-test for agility (Appendix C2) is a valid and
reliable test to measure agility requiring the athlete to
sprint forward, laterally, and backward as quickly as
possible.
24
The subject sprints forward first, then
shuffles laterally to one side, then the other (without
crossing over their feet), and then backward.
This test
was done in the Henry Gymnasium at Washington and
Jefferson College.
The athletes performed this test on
the hard wood gym floor.
Their attire included a T-
shirt, mesh shorts, and running sneakers.
The T-test for
agility was scored using the time recorded from the Speed
Trap II TimerTM.
The Speed Trap II TimerTM was used to
measure the velocity in seconds of each athlete to
determine how quickly the athlete completed the T-test
for agility.
The T-test for agility is used to measure
leg speed as well as leg power and agility.24
Procedures
9
The study was approved by the California University
of Pennsylvania Institutional Review Board (IRB)
(Appendix C4).
The researcher also obtained permission
to use Washington and Jefferson College (NCAA Division
III) athletes from the Washington and Jefferson Athletic
Director (see letter, Appendix C5).
A random sample of
volunteer subjects were obtained who had not sustained a
lower extremity injury in the past six months.
Prior to
the subjects’ involvement in the study, the researcher
explained the concept of the study and everything it
entailed to each subject in a meeting that was held prior
to the first testing date.
At this time the Informed
Consent Form (Appendix C1) was administered explaining
the procedure and need for the study as well as the risks
involved.
Each subject was informed they would be tested on
six separate days with 48 hours separating each testing
session.
Each subject was assigned a time slot so that
only one subject was participating at a time.
stretching protocol was performed twice.
Each
On each of the
testing days, the subjects’ were randomly assigned to one
of the stretching protocols; dynamic stretching, static
stretching, or no stretching by picking a S,D, or C out
of a hat.
Once a subject did a certain protocol twice,
that piece of paper was no longer included in the pool.
10
On testing day, all subjects performed a standard 5
minute jog warm-up at their own pace before any
stretching or testing.
rested for two minutes.
After the warm-up, subjects
Immediately after the two
minutes of rest, subjects were asked to perform their
randomly assigned protocol.
The active dynamic warm-up stretching protocol(ADWS)
(Appendix C4) that was used included: high knees
(gluteals and hamstrings), drop lunges (gluteals and hip
flexors), flick backs (quadriceps and hip flexors)
lateral shuffles (adductors and abductors), and heel to
toe walks (gastroc and soleus).8,9
Subjects performed 20
repetitions of each of these dynamic stretches on each
leg, walking back after each one.
The active static warm-up stretch protocol (ASWS)
(Appendix C4) that was used consisted of a gluteal
stretch, hip flexor stretch, hamstring stretch,
quadriceps stretch, adductor stretch, abductor stretch,
and a gastroc/soleus stretch, with the stretches being
held for 20 seconds each bilaterally.8
The dynamic and
static stretches were carefully chosen to correspond with
one another so that the same muscles were being stretched
for the same amount of time.
The researcher recognized
that there are eight static stretches and five dynamic
stretches, but it should be noted that the static
11
stretches are single joint motions, whereas the dynamic
stretches are multi-joint motions.
The researcher had a tape recording prepared that
instructed the subjects when to change the stretch to
ensure that the stretching was consistent.
For the
control trial, the subjects rested the same amount of
time it took to complete the protocols.
After the
subjects were finished with the assigned protocol, they
had another rest period of two minutes to prepare for
their performance test.
They then performed two trials
of the T-test for agility with a one minute rest in
between trials.
The two times were timed using the Speed
Trap II timing system, and the best time of the two
trials were recorded.
The results were recorded on the
data collection forms (Appendix C6).
This process was
repeated until the subjects performed each of the
protocols twice, to ensure a true repeated measures
design.
12
Hypotheses
The following hypotheses were based on the literature
reviewed and the information investigated when developing
this study.
H0) There will not be a significant difference in Ttest for agility time between the subjects performing
a static stretching protocol, dynamic stretching
protocol, or a no stretching protocol.
HA) There will be a significant difference in T-test
for agility time between the subjects performing a
static stretching protocol, dynamic stretching
protocol, or a no stretching protocol.
Data Analysis
All data was analyzed using SPSS version 14.0 for
Windows, with a .05 alpha level.
Scores for each group
on the dependent variable, the T-test for agility, were
used.
The research hypothesis was analyzed using a 2 X 3
repeated measures ANOVA for test (2) by condition (3).
13
Results
The purpose of this study was to examine the
differences between three stretching protocols (static
stretching, dynamic stretching, and no stretching) on the
performance of the T-test for agility in Division III
collegiate football players.
The following section
contains the data collected throughout the study.
Hypothesis Testing
The following hypotheses were tested in this study.
All hypotheses were tested with the level of significance
set at
.05.
A 2 X 3 repeated measures ANOVA for test
(2) by condition (3) was calculated comparing the time on
the T-test for agility for subjects on three different
stretching conditions: static stretching, dynamic
stretching, and no stretching.
found (F(2,34)= 5.518, p < .001.
A significant effect was
Follow-up protected t
tests revealed that times were significantly different
between static stretching (11.28±1.21 sec) and dynamic
stretching (10.99±1.15 sec), and between dynamic
stretching (10.99±1.15 sec) and the control (11.47±1.08
sec).
The pairs used in the paired t-test statistics
14
were chosen by picking the best time of the two tests for
each condition.
The T-test for agility times were found
to be significantly influenced by stretching.
Hypothesis 1 (H0):
There will not be a significant
difference in T-test for agility time between the
subjects performing a static stretching protocol, dynamic
stretching protocol, and no stretching protocol.
Hypothesis 2 (HA): There will be a significant
difference in T-test for agility time between the
subjects performing a static stretching protocol, dynamic
stretching protocol, and no stretching protocol.
Conclusion: The null hypothesis was rejected.
The
time on the T-test for agility was affected by the
stretching condition.
supported.
The alternate hypothesis was
15
Table 1. 2 X 3 repeated measures ANOVA for test (2) by
condition (3) for effect of stretching conditions on the
T-test for agility. The type of stretching condition
had a significant effect (.008) on the T-test for agility
time
Type III
Sum of
Squares
Test
Error(test)
Condition
Error Condition
Test*Condition
Error
(Test*Conditon)
Sphericity
Assumed
GreenhouseGeisser
Huynh-Feldt
Lower-bound
Sphericity
Assumed
GreenhouseGeisser
Huynh-Feldt
Lower-bound
Sphericity
Assumed
GreenhouseGeisser
Huynh-Feldt
Lower-bound
Sphericity
Assumed
GreenhouseGeisser
Huynh-Feldt
Lower-bound
Sphericity
Assumed
GreenhouseGeisser
Huynh-Feldt
Lower-bound
Sphericity
Assumed
GreenhouseGeisser
Huynh-Feldt
Lower-bound
Mean
Square
df
F
Sig.
.313
1
.313
2.795
.113
.313
1.000
.313
2.795
.113
.313
1.000
.313
2.795
.113
.313
1.000
.313
2.795
.113
1.901
17
.112
1.901
17.000
.112
1.901
1.901
17.000
17.000
.112
.112
.816
2
.408
5.518
.008
.816
1.725
.473
5.518
.012
.816
.816
1.902
1.000
.429
.816
5.518
5.518
.010
.031
2.515
34
.074
2.515
29.333
.086
2.515
2.515
32.341
17.000
.078
.148
3.037
2
1.519
21.236
.000
3.037
1.621
1.873
21.236
.000
3.037
3.037
1.768
1.000
1.718
3.037
21.236
21.236
.000
.000
2.431
34
.072
2.431
27.562
.088
2.431
2.431
30.049
17.000
.081
.143
16
Table 2. Means and Standard Deviations for the T-test for
agility times according to the stretching condition.
Mean
Std. Deviation
N
SS1
11.3367
1.36953
18
SS2
11.2800
1.21129
18
DS1
11.0728
1.21397
18
DS2
10.9978
1.14793
18
C1
11.4722
1.08099
18
C2
11.5422
1.13549
18
Table 3. Paired t-test for the means and standard
deviations for static stretching and dynamic stretching
(Pair 1), dynamic stretching and the control (Pair 2),
and static stretching and the control (Pair 3).
Pair 1
SS2
DS2
Pair 2
DS2
Pair 3
C1
SS2
C1
Mean
11.2800
10.9978
N
18
18
Std. Deviation
1.21129
1.14793
Std. Error Mean
.28550
.27057
10.9978
11.4722
18
18
1.14793
1.08099
.27057
.25479
11.2800
18
1.21129
.28550
11.4722
18
1.08099
.25479
Table 4. Paired t-test for the differences between static
stretching and dynamic stretching (Pair 1), dynamic
stretching and the control (Pair 2), and static
stretching and the control (Pair 3).
Paired
Pair 1
Pair 2
Pair 3
SS2 DS2
DS2 C1
SS2 C1
Differences
95%
Confidence
Lower
df
Sig
(2tailed)
Mean
Std.
Dev
.28222
.37905
.08934
.09373
.47072
3.159
17
.006
.49712
.11717
-.72166
.22723
-4.049
17
.001
.44764
.10551
-.41483
.03038
-1.822
17
.086
.47444
.19222
Std. Dev
Mean
t
Upper
17
Test
1
2
T-test for Agility Time (sec)
11.50
11.25
11.00
Static Stretching
Dynamic Stretching
Control
condition
Figure 1. Mean T-test for agility times of the stretching
conditions(3) with the interaction of tests(2). A
significant effect was found.
18
DISCUSSION
The following section is divided into three
subsections: Discussion of Results, Conclusions, and
Recommendations.
Discussion of Results
Stretching and flexibility training have been very
common among the athletic population, making up a large
part of training programs as well as pre-event warm-up
routines for athletes.1-15 It has been theorized by
athletes, coaches, and athletic trainers that increasing
flexibility is an important aspect of physical fitness,
leading to an increase in athletic performance as well as
reducing the incidence of injury.3,13,14,16,17-19,22
However,
recent research has found that the acute effects of
stretching may have negative results on both performance
and risk of injury.2-19 The focus of this study was to
compare static stretching, dynamic stetching, and no
stretching to see how each method affected the
performance on the T-test for agility in Division III
football players.
19
It was hypothesized that dynamic stretching would
yield faster times on the T-test for agility than static
stretching and no stretching.
Performance of the T-test
for agility was measured using the Speed Trap II timing
system23.
Statistical analysis revealed a significant
difference in performance between the three stretching
protocols.
Many of the subjects participating in the research
study also reported that the dynamic stretching protocol
was a better warm up and favor this type of stretching.
Some subjects also reported that they believed they were
faster after the dynamic stretching protocol.
The results of this study were similar to those
reported by Siatras et al21, Fletcher et al8, McMillian et
al9, and Little and Williams22.
These studies all found
significant differences between the stretching
conditions.
The study by Siatras et al, showed
significant increases in sprint time following static
stretching, however it was the only study showing no
effect following dynamic stretching.
It is important to note that all of the tests used
in these studies were anaerobic, all averaging under
twelve seconds.
In the study by Fletcher8, the 20 meter
sprint was used with times averaging around three
20
seconds.
Little and Williams22 used the 10 meter sprint
averaging two seconds, the flying 20 meter sprint
averaging 2.5 seconds, and the zig-zag agility test which
takes about 5 seconds to complete.
Faigenbaum et al11
used the 10 meter sprint as well, and Siatras et al21
measured the vaulting speed from the start of the runway
until the contact with the vault, which is about 7.5
seconds.
In this study, the T-test for agility took
about 10 seconds to complete; which is also a very short
time period.
These findings support the fact that short
distance anaerobic events positively benefit from dynamic
stretching.
Vertical jump was also looked at in studies by
Little and Williams22, and Faigenbaum et al10,11, and
significant increases in height were found following
dynamic stretching.
Other power tests such as the five
step jump and medicine ball throw were used in a study by
McMillian et al9, and were also found to improve
performance after dynamic stretching.
These results show
that explosive power tests as well as short distance
anaerobic performance benefit from dynamic stretching as
compared to static stretching.
In regards to agility, only two studies, (Siatras et
al and McMillian et al) looking at how stretching affects
21
agility testing have been published, which is why the Ttest for agility was chosen for this particular study.
As mentioned earlier, Siatras et al21 found decreases in
the time on the zig-zag agility test following dynamic
stretching, but results were not found to be
statistically significant.
Although Siatras et al did
not find significance, a significant effect was found in
the study by McMillian et al9.
This is the only other
known study to use the T-test for agility.
A separate study by Faigenbaum et al10 found that the
shuttle run performance declined significantly after
static stretching as compared to dynamic stretching.
This shows that adolescents as well as adult athletes can
benefit from dynamic stretching.
CONCLUSIONS
This study revealed that the type of stretching
protocol (Static stretching, dynamic stretching, or no
stretching) had a significant effect on the time on the
T-test for agility in Division III collegiate football
players.
The athletes in this study performed each
stretching protocol twice, followed by two trials of the
T-test for agility.
Results showed that there was a
significant decrease in agility time when preceded with
22
dynamic stretching.
In this case, knowing that dynamic
stretching positively benefited performance, it is
important to keep implementing dynamic stretching into
warm-up routines.
RECOMMENDATIONS
It is important for Certified Athletic Trainers to
be updated on the recent research regarding stretching to
be able to implement the most safe and beneficial warm-up
techniques for our athletes.
The recent literature on
this topic is in favor of dynamic stretching, however,
there are still some aspects that need to be looked at
further.
For example, the number of studies looking at
short distance sprint speed and studies looking at power
tests support the idea that dynamic stretching increases
performance.
However, the studies looking at agility are
lacking, and therefore need to be further addressed to
ensure more consistency.
One recommendation for future research would be to
look at more than one agility test within a study instead
of just picking one.
There are only a few studies using
agility tests, therefore, a study looking at a number of
agility tests would be beneficial.
If similar results
23
are found, it would provide support for the agility
studies done previously.
Another recommendation would be to compare different
anaerobic and aerobic activities in terms of the time it
takes to complete them.
As mentioned earlier there are
an abundance of studies looking at short distance events,
but very few, if any, on comparing short distance events
to endurance events.
For example, it would be
interesting to compare dynamic and static stretching
looking at the mile run.
If it is found that long
distance events positively benefit from dynamic
stretching, endurance athletes can benefit from this type
of stretching as well.
24
REFERENCES
1.
Houglum PA. Therapeutic Exercise for Athletic
Injuries. Champlain IL: Human Kinetics; 2001.
2.
Thacker SB, Gilchrist J, Stroup DF, Kimsey DC. The
Impact if Stretching on Sports Injury Risk: A
Systematic Review of the Literature. Med and Science
in Sports Exercise. 2004;36:371-378.
3.
Weerapong P, Hume PA, Kolt GS. Stretching:
Mechanisms and Benefits for Sport Performance and
Injury Prevention. Physical Therapy Reviews.
2004;9:189-206.
4.
Mann D, Whedon C. Functional Stretching:
Implementing a Dynamic Stretching Program. Athletic
Therapy Today. 2001;6:10-13.
5.
Marek SM, Cramer JT, Fincher LA, et al. Acute
Effects of Static and Proprioceptive Neuromuscular
Facilitation Stretching on Muscle Strength and Power
Output. J. Athl. Train. 2005;4094-103.
6.
Fowles JR, Sale DG. Time Course of Strength Deficit
after Maximal Passive Stretch Humans. Medicine and
Science in Sports and Exercise. 1997;29:26.
7.
Kokkonen J, Nelson AG, Cornwell A. Acute Muscle
Stretching Inhibits Maximal Strength Performance.
Research Quarterly from Exercise and Sport.
1998;69:411-415.
8.
Fletcher IM. The Effect of Different Warm-up
Protocols on 20 Meter Sprint Performance in Trained
Rugby Players. J. Strength Cond. Res. 2004;18:885888.
9.
McMillian DJ, Moore JH, Hatler BS, Talor DC. Dynamic
vs. Static-Stretching Warm Up: The Effect on Power
and Agility Performance. J. Strength Cond. Res.
2006;20:492-499.
10.
Faigenbaum AD, Bellucci M, Bernieri A, Bakker B,
Hoorens K. Acute Effects of Different Warm-up
25
Protocols on Fitness Performance in Children. J.
Strength Cond. Res. 2005;19:376-381.
11.
Faigenbaum AD, Kang J, McFarland J, Bloom JM. Acute
Effects of Different Warm-Up Protocols on Anaerobic
Performance in Teenage Athletes. Pediatr Exerc Sci.
2006;17:64-75.
12.
Knudson DV, Noffal GJ, Bahamonde RE, Bauer JA.
Blackwell JR. Stretching Has No Effect on Tennis
Serve Performance. J. Strength Cond. Res.
2004;18:654-656.
13.
Nelson AG, Driscoll NM, Landin DK, Young MA,
Schexayder IC. Acute Effects of Passive Muscle
Stretching on Sprint Performance. J. Sports Sci.
2005;23:449-454.
14.
Unick J, Kieffer SH, Cheesman W, Feeney A. The Acute
Effects of Static and Ballistic Stretching on
Vertical Jump Performance in Trained Women. J.
Strength Cond. Res. 2005;19:206-212.
15.
Lund H, Vestergaard-Poulsen P, Kanstrup IL, Sejrsen
P. The Effect of Passive Stretching on Delayed Onset
Muscle Soreness, and other Detrimental Effects
Following Eccentric Exercise. Scand. J. Med. Sci.
Sports. 1998;8:216-221.
16.
Haff GG. Roundtable Discussion: Flexibility
Training. Strength Cond. J. 2006;28:64-85.
17.
Nelson AG, Kokkonen J, Arnall DA. Acute Muscle
Stretching Inhibits Muscle Strength Endurance
Performance. J. Strength Cond. Res. 2005;19:338-343.
18.
Church BJ, Wiggins MS, Moode MF, Crist R. Effect of
Warm-Up and Flexibility Treatments on Vertical Jump
Performance. J. Strength Cond. Res. 2001;15:332-336.
19.
Witvrouw E, Mahieu N, Danneels L, McNair P.
Stretching and Injury Prevention: An Obscure
Relationship. Sports Med. 2004;34:443-449.
20.
Papadopoulos G, Siatras T, Kellis S. The Effect of
Static and Dynamic Stretching Exercises on the
Maximal Isokinetic Strength of the Knee Extensors
26
and Flexors.Isokinetics and Exercise Science.
2005;13:285-291.
21.
Siatras T, Papadopoulos G, Mameletzi D, Kellis S.
Static and Dynamic Acute Stretching Effect on
Gymnasts’ Speed in Vaulting. Pediatr Exerc Sci.
2003;15:383-391.
22.
Little T, Williams A. Effects of Differential
Stretching Protocols During Warm-ups on High-Speed
Motor Capacities in Professional Soccer Players. J.
Sports Sci. 2004;22:589-590.
23.
Brower Timings Systems. http://www.browertiming.com.
Accessed October 22, 2006.
24.
Pauole K, Madole J, Garhammer M, Rozenek.
Reliability and Validity of the T-test for agility
as a measure of agility, leg power, and leg speed in
college-aged men and women. J.Strength Cond. Res.
14:443-450. 2000.
27
APPENDIX A
Review of Literature
28
REVIEW OF THE LITERATURE
This review of literature will examine the effects
of dynamic and static stretching as part of a warm-up
protocol, and how they affect an athlete’s performance.
Research done previously on this topic will be analyzed
and discussed to support this subject matter.
Traditionally, static stretching (holding a stretch
position for a period of time with little or no movement)
has been the common method of stretching used before an
athletic event.2-20
However, dynamic stretching
(controlled movement through the active range of motion),
is becoming more and more popular in the field of
athletic performance.2,3,5,7,9,12-16,19-24,25,30 This review of
literature is divided into four sections: 1) Stretching
and Flexibility, 2) Stretching and Power, 3) Stretching
and Performance, and 4) Stretching and Injury Risk.
summary of the literature review is also included.
A
29
Stretching and Flexibility
The act of stretching has been a component of the
traditional method of warm-up by athletes prior to
athletic events at all levels of competition.
The recent
literature concerning whether stretching is more harmful
than beneficial is a concern among athletic trainers
everywhere.
However, before examining the literature on
stretching in relation to performance as well as injury
risk, it is necessary to understand the workings of the
muscle-tendon unit.
Mechanisms of Stretching
Flexibility refers to the musculotendinous unit’s
(MTU) ability to elongate with the application of a
stretching force, determining the range of motion
available at a joint.1,2
Therefore, the act of stretching
can be defined as movement applied by an external or
internal force in order to increase muscle flexibility
and/or joint range of motion.3
It is important to
understand what is occurring physiologically when a
muscle responds to a stretching force.
To grasp this
concept it is necessary to begin with the basic anatomy
of the MTU.
30
The MTU is made up of muscle cells, nerves,
connective tissue, and blood vessels.
Each muscle cell
is called a muscle fiber, which are cylindrical and
arranged parallel to one another.
They run the entire
length of an individual muscle and are held in place by
connective tissue.4-6
Proprioceptors, known as muscle
spindles, are located within the body of the muscle and
are parallel to the other muscle fibers.
These muscle
spindles are surrounded by special sensory nerves that
produce impulses when the length and rate of the muscle
spindle is altered.
When the muscle spindles are
stimulated, a reflexive response is created which causes
the muscle to contract, also causing an inhibition of the
antagonist muscle.1,4-6
The muscle contracts when it is
put on a stretch, to prevent the overstretching of the
muscle.
This excitation of the muscle spindles causing a
reflex contraction of the stretched muscle is known as
the stretch reflex.1,4-6
There are also proprioceptors called golgi tendon
organs (GTO) which sense tension in the muscle.
GTO’s
are sensory nerve endings that are wrapped around the
fibers of tendons.
When GTO’s are stimulated by sensing
increased muscle tension, there is a reflex inhibition in
the muscle where tension is being produced.
This reflex
31
provides a negative feedback mechanism, preventing too
much tension in the muscle, thus protecting it from
injury.1-6
Force deformation is the amount of force that is
applied when putting a muscle on a stretch, to change the
length of the tissue.
If the force is applied too
quickly and is too much for the tissue to tolerate, the
muscle spindles and GTO’s do not have enough time to
respond and injury can result.1
When tissues are held
at a constant force, the deformation continues, causing a
change in the tissue length.
This is known as creep.
The effect of creep can be affected by how much time the
load is applied.
For example, a load that is applied for
a longer time such as a static stretch, causes a greater
increase in tissue length than a load that is applied and
released more quickly.1,3
Stretching Techniques
There are a number of different stretching
techniques used in athletics, depending on various
factors, such as the type of sport, the athlete or
coach’s preference, or even the training program a team
may be using.
The four most common techniques that are
widely used in the sport setting are static,
32
Proprioceptive neuromuscular facilitation (PNF),
ballistic, and dynamic.1-3,8
Static stretching is the most common and traditional
stretching technique used in the athletic setting.
Static stretching can be defined as holding a stretch for
a period of time with little or no movement.8
This type
of stretching has been found to increase musculoskeletal
flexibility by affecting both the mechanical and
neurological properties of the muscle tendon unit.3
However, there is evidence that puts the effectiveness of
static stretching into question, suggesting that it may
not be the most beneficial method and may even decrease
performance and increase injury rates.1-3,8,10,12,15-18,21-27,31,32
Many sports require the use of bursts of speed from a
slowly moving or stationary position, such as a track or
swimming start.
Using static stretching as part of a
warm-up for these types of sports might not prepare the
muscles as well as stretching that incorporates
functional movements as in dynamic stretching.8,32
Proprioceptive neuromuscular facilitation was
developed in the 1950’s and includes several techniques
to increase flexibility such as slow-reversal-hold,
contract-relax, and hold-relax.
These techniques use a
combination of both contraction and relaxation of both
33
agonist and antagonist muscles.1,8
PNF has been thought
to cause a greater improvement in range of motion as
compared to static stretching.8
In a study that compared
dynamic, static, and PNF stretching by Lucas and Koslow,9
it was found that all three methods of stretching
produced significant increases in flexibility from pretest to posT-test for agility.
Ballistic stretching is a rhythmic bouncing type of
movement that repeatedly produces high levels of tension
very rapidly.10 This type of stretch is not quite as
common due to the fact that it is thought to be more
harmful than the other techniques.
During this type of
stretch, the muscle is stretched very quickly and then
released quickly producing high levels of tension very
rapidly within the muscle tendon unit.
This does not
allow enough time to release the tension or increase the
length, creating a high level of tension development,
which may cause harm to the athlete.3,8,10
Although the uncontrolled bouncing type of ballistic
stretching is not suggested in athletics, controlled
movement through stretching, known as dynamic stretching,
is becoming very popular and can be very beneficial as a
warm-up.
Shellock and Prentice11 reported in their review
of stretching that dynamic stretching is essential in
34
athletic performance because it is important for joints
to be capable of moving through the available range of
motion while the muscle is put on a stretch.3,11
This
allows the athlete to go through sport specific movements
while putting their muscles on a stretch, much like they
will be doing in practice or competition.10
Stretching and Power
Pre-exercise stretching has not only been linked to
injury risk and decreases in sport performance, but may
also decrease a muscle’s ability to produce force,
reducing an athlete’s strength.
There are two primary
theories proposed to explain this stretching-induced
strength deficit.
The first is linked to the mechanical
factors of the muscle such as changes in length tension
relationships, and the second theory relates to the
neuromuscular factors, such as decreased motor unit
activation.12,13
Researchers have also proposed that the
mechanism for this stretching induced strength deficit
may be related to a decrease in muscle stiffness that
could in turn, alter the length tension relationship of
the muscle fibers.12,13
35
There have been many recent studies looking at the
acute effect of stretching on muscle strength and power.
The majority of these studies have found that of all the
stretching techniques, static stretching had a negative
affect on maximal performance of peak torque as a measure
of strength.13-17 In a study by Marek et al12 it was
hypothesized that stretching may have altered the lengthtension relationship, as well as the plastic deformation
of the tissues, resulting in the force production being
limited.
Static and PNF stretching techniques were
compared examining both peak torque, mean power, and
active and passive range of motion.
Peak torque and mean
power were both reduced following both the static and PNF
stretching.12
A study by Papadopoulos et al14 was conducted to
examine the effect of static and dynamic stretching
exercises on the maximal isokinetic torque of the knee
extensor and flexor muscles.
The results showed a
significant difference on maximal isokinetic torque of
these muscles following the two different stretching
techniques.
The torque was significantly reduced with
the static stretching exercises, while no effect was seen
when preceded with the dynamic stretching exercises.
A
similar study by Fowels et al15 found that when looking at
36
the maximal isometric torque of the plantar flexor
muscles, torque was reduced by 30% after a static
stretching regimen immediately afterward.
Sixty minutes
after the stretching took place, isometric torque was
still reduced by 9%.15 This length of time shows that preexercise stretching may negatively affect athletes’
ability to produce peak torque in their sport as the
reduction lasts for at least 60 minutes.
Another study
found there to be a reduction in isometric torque after a
few minutes of static stretching, however, torque was
back to normal 10 to 15 minutes later.16 In a study by
Nelson et al17 it was found that when prone knee flexion
exercises were performed at 60% as well as 40% of body
weight, static stretching significantly reduced strength.
The results of this study suggest that static stretching
exercises should be avoided prior to performances
requiring maximal strength production.17
Stretching and Performance
In addition to static stretching as part of a warmup resulting in a decrease in strength production, this
stretching technique has been linked to a decrease in
performance level as well.18-22
This is a major problem
37
for athletes, as their main goal of competing is to
achieve the best performance possible to succeed in their
sport.
The most common reasoning behind this decrease in
performance following static stretching is that it causes
the musculotendinous unit to become more compliant, which
decreases stiffness, thus, reducing the force
development.18
The reduction in the stiffness in the
musculotendinous unit leads to neural inhibition,
reducing the neural drive to the muscle.
Finally, this
leads to a reduction in force and power output.
Each
muscle fiber in the body has a range in which it has the
best available force production.
When that length is
exceeded, as with sustained static stretching, the
potential force production drops considerably.1
The
recent research on static stretching and its negative
effect on sport performance and injury risk has
interested sports medicine professionals in learning more
about the most effective warm-up methods to positively
benefit performance.18,20-22
stretching.
One answer may be dynamic
Although there has not been an abundance of
studies performed on this topic thus far, the majority of
the research examining the different warm-up stretch
protocols is consistent, in favor of dynamic
stretching.18,20-22
38
A study by Fletcher
18
was performed to determine the
effect of different static and dynamic stretch protocols
on a 20 meter sprint performance in trained rugby
players.
It was found that the groups participating in
the static stretching warm-up had a significant increase
in their sprint time from their pretest time.
This
decrease in performance was theorized to have been due to
an increase in the musculotendinous unit compliance,
which in turn led to a reduction in the ability of the
MTU to store energy.
The dynamic stretching groups
decreased their sprint times significantly, which could
be linked to the movement patterns being so similar to
the actual movements and coordination required for
sprinting.
These results showed that dynamic stretching
as a pre-participation warm-up increased performance,
whereas static stretching significantly decreased
performance.18
Similarly, in a study by Siatras et al19
examining gymasts’ vaulting speeds, it was found that
vault speeds were significantly decreased following
static stretching exercises.
There was no effect on the
performance of the dynamic stretching protocol, which
could be attributed to neurological mechanisms.19
In contrast, Little and Williams20 found static
stretching not to be detrimental to the velocity
39
performance in professional soccer players.
However,
dynamic stretching was found to be the most effective as
a warm-up for performance producing significantly faster
10m sprint, 20m sprint, and agility times than either a
non-stretch protocol or a static stretching protocol.20
Dynamic stretching was also found to be the most
effective stretching technique in a study by McMillian et
al,21 revealing better performance scores in the T-shuttle
run, medicine ball throw, and the 5-step jump as compared
to static stretching and no stretching.21
Two very similar studies, conducted by Faigenbaum et
al(22,23) looked at the acute effects of different warm-up
protocols on the performance of young children and
adolescents.
Results were consistent in both studies,
showing that pre-event dynamic stretching alone or in
conjunction with static stretching is more beneficial
than static stretching alone in relation to performance
in both teenage athletes as well as younger children.22,23
A study conducted by Knudson et al24 solely examining the
effect of static stretching on the speed and accuracy of
a tennis serve performance found no significant
difference when incorporating static stretching as a part
of the warm-up as compared to no stretching at all.
This
study suggests that as static stretching may negatively
40
affect many types of performances, it does not
necessarily affect the performance of a tennis serve.24
Another study by Nelson et al25, also investigated the
effects of static stretching on a 20 m sprint
performance, without the comparison of a dynamic
stretching group.
Contradictory to Knudson’s study,
Nelson found there to be a significant increase in the 20
meter sprint times of Division I NCAA track athletes who
engaged in a pre-event static stretching protocol as
compared to no stretching at all.25
A number of studies
have looked at jump performance as a test after different
stretching protocols have been performed.
A study by
Unick et al26 found no significant difference in vertical
jump scores when comparing static and ballistic
stretching.
In a study comparing static stretching,
proprioceptive neuromuscular facilitation and a control
group by Church et al,27 results showed a significant
decrease in vertical jump performance for the PNF
stretching group as compared to the static stretching and
control groups.27
Although there is still some contradictory evidence
regarding static and dynamic stretching, the majority of
recent literature examining the effects of these
stretching techniques is in support of dynamic
41
stretching.18-23
The benefits obtained from this technique
are thought to stem from facilitated motor control from
rehearsing the specific movements before the actual
event, increased muscle blood flow and elevated core
temperature.
This elevated temperature increases the
sensitivity of nerve receptors as well as increases the
speed of nerve impulses, which in turn causes muscle
contractions to be faster and more forceful.21-23
Stretching and Injury Risk
Along with a decrease in performance and muscle
strength, static stretching also has been linked to an
increased risk of injury.
The literature concerning
stretching and injury risk is minimal and needs to be
further researched.
Injury may be related to either too
much or too little flexibility, and in some instances
increasing flexibility may increase the rate of
injury.2,29-31
There are, however, some sports that
require this increase in flexibility such as gymnastics
or wrestling, however it has been found that increased
flexibility before competition may compromise muscle
performance for up to one hour.2
42
Evidence exists from randomized trials noting that
pre-exercise stretching using a specific stretching
protocol does not result in a reduction of injury risk.
Shrier28 noted five theoretic arguments against preexercise stretching for injury prevention.
The first
argument deals with the compliance, or the length change
in a muscle when a force is applied.
Increased muscle
compliance is related to a decreased ability to absorb
energy at rest.
However, a contracting muscle can absorb
more force, but is less compliant.
Therefore, stretching
does increase the compliance, however this is not related
to the tissue’s resistance to injury.28,29
Shrier’s second
argument is related to the sarcomere length.
When the
sarcomeres are stretched to the point at which the actin
and myosin do not overlap, this causes fiber damage.
The
third is that muscle compliance may be irrelevant to
injury.
The fourth argument is that the muscle tissue
compliance during activity and at rest is unrelated.
If
stretching increases compliance at rest, this indicates
that stretching does not support the fact that when the
muscle is active there is a decrease in injury risk.
Lastly, Shrier28 argues that increased range of motion may
be a result of an increase in stretch tolerance.
Therefore, stretching does not increase tissue
43
compliance, it merely increases the stretch tolerance
during the stretching procedure.
A study by Johansson et al30 investigated the effects
of pre-exercise stretching on delayed onset muscle
soreness (DOMS).
No significant difference was found
between the stretched and the non-stretched limbs.
A
very similar study by Lund et al31 also looked at passive
stretching on DOMS as well as on dynamic muscle strength,
plasma creatine kinase concentration, and the ratio of
phosphocreatine to inorganic phosphate following
eccentric exercise.
It was concluded that passive
stretching did not have any significant influence on
increased plasma creatine phosphate concentration, muscle
pain, or muscle strength.
These two studies suggest that
passive static stretching done either pre or post
exercise, has no effect on muscle soreness, or decrease
in force production.30,31
Summary
Stretching is performed in athletic events everyday,
and it is very important for athletic trainers to
understand the physiological workings of the
musculotendinous unit to have a better understanding of
44
what is actually going on when a muscle is put on a
stretch.
This background information as well as reading
the recent literature can be very beneficial in choosing
the correct stretching techniques for your athletes.
Despite the inconsistent evidence pertaining to these
stretching techniques, all of these types of stretching
are used in the athletic setting.
Overall, the results obtained from the studies
related to strength and power, indicate that static
stretching negatively effects strength production.13-17
This information should be used by strength and
conditioning professionals, athletic trainers, coaches,
and athletes to help achieve the most optimal level of
strength performance.
Future research should be carried
out to support these findings and to find the underlying
mechanisms that cause this decrease in maximal force
production for individuals participating in athletics.
The compiled findings from the recent literature
related to performance are, for the most part, in
accordance with each other.
The previously examined
studies have shown that static stretching may be
detrimental to an athlete’s performance, favoring dynamic
stretching, which is shown to be much more beneficial.1823,25
These results have led to a great deal of interest
45
from coaches, athletes, and athletic trainers, who are
beginning to move away from the traditional method of
static stretching and incorporating dynamic stretching
into their warm-up routines.18,20-22
The results of the literature dealing with
stretching and injury risk are conflicting, with some
studies suggesting that stretching has no effect on
injury or muscle soreness and others that do not support
pre or post exercise stretching at all, due to its
supposed detrimental effects.2,29-31
This is an area of
concern, and there is a need for further studies to be
conducted to build on these previous findings.
46
APPENDIX B
The Problem
47
The Problem
Statement of the Problem
It has been previously accepted in the athletic
population that increasing flexibility promotes increased
performance and decreases the risk of injury.3,10,17,25-27,32
Stretching is incorporated in many aspects of sports,
especially in warm-up and cool down exercises, and are
performed everyday.1-3,8,12,15,16,18,21-26,31
However, recent
research suggests that performing static stretching
before performance may contribute to increased injury and
a decrease in performance, which can be detrimental to
the health and abilities of our athletes.1-3,8,10,12,15-18,2127,31,32
Dynamic stretching is becoming more and more
popular and could be a helpful alternative to the
traditional method of static stretching.18-23
The purpose
of this study is to compare the effect of static and
dynamic stretch protocols on the performance of the Ttest for agility in Division III Collegiate football
players.
48
Definition of Terms
The following definitions of terms will be defined
for this study:
Operational Definitions:
1) Dynamic stretching protocol – Stretching protocol
including high knees, drop lunges, flick backs,
lateral shuffles, and heel to toe walks.
The
subjects will perform 20 repetitions on each leg.
2) Static stretching protocol – stretching protocol
including a gluteal stretch, hip flexor stretch,
hamstring stretch, quadriceps stretch, adductor
stretch, abductor stretch, and a gastroc/soleus
stretch, with the stretches being held for 20
seconds each bilaterally.
3) T-test for agility - test to measure agility
requiring the athlete to sprint forward, laterally,
and backward as quickly as possible.
The subject
will sprint forward first, then shuffle
laterally
to one side, then the other (without crossing over
their feet), and then backward.
The subjects will
be put through this test to see how their times
differ following the different stretching
protocols.
49
Basic Referenced Definitions:
1) Agility - the ability to control the direction of a
body or its parts during rapid movement.1
2) Flexibility – The musculotendinous’s ability to
elongate with the application of a stretching force,
determining the range of motion available at a
joint.1,2,4-6
3) Stretching - movement applied by an external or
internal force in order to increase muscle
flexibility and/or joint range of motion.3
4) Dynamic stretching - controlled movement through the
active range on motion.3,11
5) Static stretching – holding a stretch for a period
of time with little or no movement.8
6) Proprioceptive Neuromuscular Facilitation (PNF)stretching technique that includes the combination
of alternating contraction and relaxation of both
agonist and antagonist muscles.1,3
7) Ballistic Stretching – rhythmic bouncing movement
that repeatedly produces high levels of tension
rapidly.10
8) Force deformation – musculotendinous unit’s ability
to elongate with the application of a stretching
force, determining the range of motion available1,2
50
9) Golgi tendon organ (GTO) – sensory nerve endings
located in the tendons that sense changes in muscle
tension.
Through connections with motor neurons in
the spinal cord, it inhibits the contracting muscle
protecting it from injury.1,4-6,8
10)
Muscle spindles – proprioceptors found in skeletal
muscle that are sensitive to stretch, and signals
muscle length and rate of change in the muscle’s
length.1,4-6
11)
Stretch reflex – response to a muscle being
stretched whereas the excitation of the muscle
spindles causes a reflex contraction of the
muscle.1,4,5,6,8
Basic Assumptions
The following were basic assumptions of this study:
1) The subjects did not perform any other stretching
then the stretching asked of them in this study.
2) The subjects performed the T-test for agility to
the best of their ability.
3) The equipment was calibrated and utilized properly
during the course of this study.
4) The T-test for agility is a valid and reliable
performance test.
51
Limitations of the Study
The following are limitations for this study:
1) The results can only be generalized to Division III
football players.
2) The 5 minute jog warm-up was done at the subject’s
own pace, making it difficult to measure and ensure
consistency.
3) The subjects are volunteers.
4) The same person will serve as the researcher, the
data collector and the Athletic Trainer.
Significance of the Study
Traditionally, stretching and flexibility training
have been very common in the world of athletics, making
up a large part of training programs as well as pre-event
warm up activities for athletes.
1-3,8,12,15,16,18,21-26,31
It
has long been theorized that increasing flexibility is
one of the most important elements of physical fitness,
contributing to enhanced athletic performance and
reducing the incidence of injury.3,10,17,25-27,32
However,
recent research has found that the acute effects of
stretching may have negative results on both performance
and risk of injury.
1-3,8,10,12,15-18,21-27,31
Studies have shown
that intense static stretching may predispose athletes to
52
musculoskeletal injury rather than preventing injuries
from occurring.
The effects of increased flexibility
after stretching are attributed to a decrease in the
muscle-tendon unit as well as decreasing joint stability,
making athletes more prone to injury.18,27 In addition to
this, it has also been reported that stretching before
participation may cause a decrease in muscle strength and
power output, jumping performance, and sprint
performance.3,12,13,17,18,19-23,25-27
If this new research is
valid, Athletic Trainers need to be aware of this
information to implement the most safe and beneficial
warm-up techniques for our athletes.
These recent
developments regarding this issue have caused many
coaches, athletes, and Athletic Trainers to move away
from static stretching as a warm-up, and instead
implement dynamic stretching18,20-22
Dynamic stretching can be defined as a controlled
movement through the active range of motion for each
joint.18 Although dynamic stretching is becoming more
popular, the literature examining its effect as a warm-up
seems to be lacking.
Our primary concern as Athletic
Trainers is providing the best possible care for our
athletes.
If evidence shows that one stretching
technique is not as effective as another, especially if
53
it causes harm to a patient, it is vital that we change
our protocol to be the most beneficial to the patient.
Thus, if dynamic stretching is more effective as a warmup than static stretching, additional research should be
performed to apply validity and reliability to the study
to begin implementing this change.
54
APPENDIX C
Additional Methods
55
APPENDIX C1
Informed Consent Form
56
Informed Consent Form
1. "Jaclyn C. Oakley, who is the researcher, has
requested my participation in a research study at this
institution. The title of the research is The Effect of
Static and Dynamic Stretching Protocols on Performance in
Division III Football Players.''
2. "I have been informed that the purpose of the research
is to compare the effect of static stretching, dynamic
stretching, or no stretching on the performance of the
T-test for agility in Division III Collegiate football
players." I understand that 21 members of the football
team will be tested for research purposes.
3. "My participation will involve filling out an informed
consent form before beginning the study. For the
experimental portion of the study, I will be asked to
jog for 5 minutes as a warm-up. I will then be asked
to do either an active dynamic stretch protocol, an
active static stretch protocol, or no stretching,
followed by two trials of the T-test for agility. I
will participate in this study on six separate days so
that I complete each stretching protocol twice.
4. "I understand there are foreseeable risks or
discomforts to me if I agree to participate in the study.
The possible risks and/or discomforts include possible
soreness due to activity. To minimize these risks and
discomforts the researcher has included a proper warm-up
consisting of a 5 minute jog before participating in the
performance testing.”
57
5. "I understand that in case of injury I can expect to
receive treatment or care in Washington and Jefferson’s
Henry Gymnasium, which will provided by the student
researcher, Jaclyn Oakley, or another Certified
Athletic Trainer, either of whom can administer
emergency and rehabilitative care. Additional services
needed for prolonged care past 3 days will be referred
to the team physician. I understand that I will be
responsible for payment of any services provided by the
team physician or other medical professional above or
beyond those provided by the student researcher or
other Athletic Trainer.”
I
6." There are no feasible alternative procedures
available for this study."
7. "I understand that the possible benefits of my
participation in the research are to provide more current
research, adding to the existing research, which will
contribute to which type of stretching protocol will be
the most effective in terms of improving performance as
well as decreasing injury in athletics.”
8. "I understand that the results of the research study
may be published but that my name or identity will not be
revealed. In order to maintain confidentiality of my
records, Jaclyn C. Oakley will maintain all documents in
a secure location in which only she, the student
researcher and research advisor can access."
Confidentiality will be maintained by the subjects being
assigned a number and will be referred to only by those
numbers during the testing.”
9. "I have been informed that I will not be compensated
for my participation."
10. “I have been informed that any questions I have
concerning the research study or my participation in it,
before or after my consent, will be answered by Jaclyn C.
Oakley, oak3434@cup.edu, 947 Cross Street Apt.1,
California, PA 15419, (570)449-2498, and Dr. Ben Reuter,
reuter@cup.edu, Dept of Health Science and Sport Studies,
Box 14, California University of Pennsylvania, 15419,
(724) 938-4356.”
11. "I have read the above information. The nature,
demands, risks, and benefits of the project have been
58
explained to me. I knowingly assume the risks
involved, and understand that I may withdraw my
consent and discontinue participation at any time
without penalty or loss of benefit to myself. In
signing this consent form, I am not waiving any legal
claims, rights, or remedies. A copy of this consent
form will be given to me upon request."
Subject’s name (print) ______________________________
Subject's
signature________________________________________________
Date________________
12. "I certify that I have explained to the above
individual the nature and purpose, the potential
benefits, and possible risks associated with
participation in this research study, have answered
any questions that have been raised, and have
witnessed the above signature."
13. "I have provided the subject/participant a copy of
this signed consent document if requested."
Investigator’s
signature________________________________________________
Date________________
Approved by the California University of Pennsylvania IRB
59
APPENDIX C2
Functional Testing and Equipment
60
T-test for agility
http://www.scrum.com
61
Speed Trap II Timer™
http://www.powersystems.com/nav/closeup.aspx?c=19&g=1354#
62
APPENDIX C3
Stretching Protocols
63
Active Static Warm-up Stretching Protocol
Stretch
Muscles
Sets
Repetitions
Gluteal
stretch
Gluts
1
20 sec
bilaterally
Hip Flexor
stretch
Hip Flexors
1
20 sec
bilaterally
Hamstring
stretch
Hamstrings
1
20 sec
bilaterally
Quadriceps
stretch
Quadriceps
1
20 sec
bilaterally
Abductor
stretch
Abductors
1
20 sec
bilaterally
Adductor
Stretch
Adductors
1
20 sec
bilaterally
1
20 sec
bilaterally
Gastroc/soleus Gastroc/Soleus
stretch
64
Active Static Warm-up Stretching Protocol
a.
b.
c.
d.
e.
f.
g.
a.)hamstring stretch b.) quadriceps stretch c.) adductor
stretch d.) gluteal stretch e.) hip flexor stretch f.)
gastroc/soleus stretch g.)abductor stretch
65
Active Dynamic Warm-up Stretching Protocol
Stretching
exercises
High Knees
Muscles
Gluts/Hamstrings
Sets
Repetitions
1
20
Bilaterally
Drop Lunges
Gluts/
Hip Flexors
1
20
Bilaterally
Flick Backs
Quadriceps/Hip
Flexors
1
20
Bilaterally
Lateral
Shuffles
Abductors/Adductors
1
20
Bilaterally
Heel to Toe
Walk
Gastroc/soleus
1
20
bilaterally
66
Active Dynamic Warm-up Stretching Protocol
a.
b.
c.
d.
e.
a.)
high knees b.) flick backs c.) lateral shuffles
d.) drop lunge walk e.) heel to toe walk
67
APPENDIX C4
Institutional Review Board
68
69
Please attach a typed, detailed summary of your project AND complete items 2
through 6.
1. Provide an overview of your project-proposal describing what you plan to do and how
you will go about doing it. Include any hypothesis(ses)or research questions that might
be involved and explain how the information you gather will be analyzed. For a complete
list of what should be included in your summary, please refer to Appendix B of the IRB
Policies and Procedures Manual
* The purpose of this study is to compare the effects of dynamic stretching, static stretching,
and no stretching on performance. The main hypothesis of this study is that there will not be
a difference between static stretching, dynamic stretching, and no stretching on the time to
complete the T-test for agility. All data will be analyzed using SPSS version 14.0 for
Windows, with a .05 alpha level. Scores for each group on the dependent variable, the T-test
for agility, will be used. Hypothesis one will be analyzed using a repeated measures ANOVA.
2. Section 46.11 of the Federal Regulations state that research proposals involving human
subjects must satisfy certain requirements before the IRB can grant approval. You
should describe in detail how the following requirements will be satisfied. Be sure to
address each area separately.
a. How will you insure that any risks to subjects are minimized? If there are
potential risks, describe what will be done to minimize these risks. If there are
risks, describe why the risks to participants are reasonable in relation to the
anticipated benefits
* The possible risks and/or discomforts include possible soreness due to activity. To
minimize these risks and discomforts the researcher has included a proper warm-up
consisting of a 5 minute jog before participating in the performance testing. In case of
injury the subject can expect to receive treatment or care in the Henry Gymnasium at
Washington and Jefferson College, which will provided by the student researcher, Jaclyn
Oakley, or another Certified Athletic Trainer, either of whom can administer emergency
and rehabilitative care. Additional services needed for prolonged care past 3 days will
be referred to the team physician. The subjects understands that they will be responsible
for payment of any services provided by the team physician or other medical professional
above or beyond those provided by the student researcher or other Athletic Trainer.”
b. How will you insure that the selection of subjects is equitable? Take into account
your purpose(s). Be sure you address research problems involving vulnerable
populations such as children, prisoners, pregnant women, mentally disabled
persons, and economically or educationally disadvantaged persons. If this is an
in-class project describe how you will minimize the possibility that students will
feel coerced.
* The purpose of the research is to compare the effect of static stretching, dynamic
stretching, or no stretching on the performance of the T-test for agility in Division III
Collegiate football players. In this study it is pertinent to use 21 members of the
football team to determine which stretching technique will most benefit the athletes.
Participation will be voluntary.
c. How will you obtain informed consent from each participant or the subject’s
legally authorized representative and ensure that all consent forms are
70
appropriately documented? Be sure to attach a copy of your consent form to the
project summary.
*The subject’s participation will involve filling out an informed consent form before
beginning the study.
d. Show that the research plan makes provisions to monitor the data collected to
insure the safety of all subjects. This includes the privacy of subjects’ responses
and provisions for maintaining the security and confidentiality of the data.
*The results of the research study may be published but the names or identity of the
subjects will not be revealed. In order to maintain confidentiality of the subjects’
records, Jaclyn C. Oakley will maintain all documents in a secure location in which
only the student researcher and research advisor can access. Confidentiality will be
maintained by the subjects being assigned a number and will be referred to only by
those numbers during the testing.
3. Check the appropriate box(es) that describe the subjects you plan to use.
Adult volunteers
Mentally Disabled People
CAL University Students
Economically Disadvantaged People
Other Students
Educationally Disadvantaged People
Prisoners
Fetuses or fetal material
Pregnant Women
Children Under 18
Physically Handicapped People
Neonates
4. Is remuneration involved in your project?
5. Is this project part of a grant?
information:
Yes or
Yes or
No
No. If yes, Explain here.
If yes, provide the following
Title of the Grant Proposal
Name of the Funding Agency
Dates of the Project Period
6.
Does your project involve the debriefing of those who participated?
Yes or
No
If Yes, explain the debriefing process here.
7. If your project involves a questionnaire interview, ensure that it meets the requirements
of Appendix __ in the Policies and Procedures Manual.
71
72
APPENDIX C5
Athletic Director Consent Form
73
74
APPENDIX C6
Data Collection Sheet
75
Agility time on the T-test for agility
Subject
Number
Dynamic
Stretching
Static
Stretching
Best
T1
T2
Best
T1
T2
No
Stretching
(control)
T1
T2
Best
76
Agility Time on the T-test for agility
Subject
Number
Dynamic
Stretching
Static
Stretching
Best
T1
T2
Best
T1
T2
No
Stretching
(control)
T1
T2
Best
77
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81
ABSTRACT
TITLE:
THE EFFECT OF DYNAMIC AND STATIC
STRETCHING ON PERFORMANCE
Researcher:
Jaclyn C. Oakley
Advisor:
Dr. Ben Reuter
Date:
4/20/07
Research Type:
Master’s Thesis
Purpose:
The purpose of this study was to
examine the differences between three
stretching protocols on the
performance of the T-test for agility
in Division III collegiate football
players.
Problem:
Recent research has found that the
acute effects of stretching may have
negative results on both performance.
Method:
Eighteen male subjects from a
Division III football team,
volunteered for this study. Each
subject was tested on six separate
days. All subjects performed a 5
minute jog warm-up first. Subjects
then rested for two minutes.
Subjects then performed their
randomly assigned protocol. They had
another rest period of two minutes.
They performed two trials of the Ttest for agility with one minute rest
in between trials. The best time was
recorded.
Findings:
A significant effect was found
(F(2,34)= 5.518, p < .001.)
Conclusion:
This study revealed that the type of
stretching protocol has a significant
effect on agility performance in
Division III collegiate football
players.