1
Chapter 1
INTRODUCTION
Strength and Conditioning coaches have continued to formulate the best training
plans to improve overall performance for their athletes. It can also be agreed upon that
many coaches have come to the consensus that one of the most critical components of
training is having an impeccable pre-event warm-up strategy. Prepping the body by
enhancing blood flow, stimulating the central nervous system (CNS), and/or allow for
pain-free range of motion prior to training is critical. Ignoring these components can have
negative consequences on performance.
The warm-up should be structured in such a way that allows for increases in
flexibility or pain-free range of motion (ROM) at the joint to promote optimized levels of
physical performance (Shellock& Prentice, 1985; Smith, 1994); and/or simply to reduce
the potential for injury (Ekstrand, Gillquist, Moller, Oberg, & Liljedahl, 1983; Safran,
Seaber, & Garrett, 1989). However, the structure of the warm-up, especially the type of
stretch component incorporated as part of the warm-up, has been of great debate over the
past years. There has been conflicting evidence presented previously in terms of the
preferredtype of stretch component of the warm-up and its effect on performance. There
are a number of stretching modalities that have been used as part of the warm-up process.
They include: Static (SS), dynamic (DS), ballistic (BS), and proprioceptive
neuromuscular facilitation (PNF) stretching. Both SS and PNF have been examined and
have been associated with decreases in strength, power, and running speed (Bacurau,
2
Monteiro, Ugrinowitsch, Tricoli, Cabral, &Aoki, 2009; Flethcer & Anness, 2007; Herda,
Cramer, Ryan, McHugh, & Stout, 2008; Samuel, Holcomb, Guadagnoli, Rubley, &
Wallmann, 2008; Sayers, Farley, Fuller, Jubenville, & Caputo, 2008; Young & Elliot,
2001).Dynamic stretching on the other hand has been shown to increase short-term highintensity muscular performance (Faigenbaum, Belluci, Bernieri, Bakker, & Hoorens,
2005; Fletcher & Jones, 2004; Holt & Lambourne, 2008; Little & Williams, 2006; Mohr,
Pink, Elsner, & Kvitne, 1998; Pearce, Kidgell, Zois, & Carlson, 2009).
Active isolated stretching (AIS) is another stretching modality available that has
been implemented by clinicians, therapists, personal trainers, and professional athletes.
AIS involvesa two second stretch, while simultaneously contracting the agonist muscle,
thus creating a neurological response called reciprocal inhibition. The end result is a
further relaxation of the antagonist muscle and an improved response to stretching
(Kochno, 2002). AIS was developed by Aaron Mattes, kinesiologist, and Jim and Phil
Wharton, regular columnists for Runner's-World magazine highly endorse this form of
stretching (Mattes, 1996). Research involving AIS is limited to only three studies that
examined the effect of AIS on range of motion (Leimohn, Mazis, & Zhang, 1999;
Marino, Ramsey, Otto, &Wygand, 2001; Middag & Harmer, 2002). However, no prior
research on AIS is available to assess its effectiveness as part of a warm-up for sports
performance.
3
Statement of Purpose
The purpose of this study was to examine the effect of implementing AIS as part
of a warm-upon vertical jump performance in division on male soccer players.
Significance of Thesis
To date, there is no available research concerning the effect of combining a warmup with AIS. And no previous research is available on the effect AIS has on overall
athletic performance. After an extensive review of literature, research suggests dynamic
stretching is the best form of stretching for pre-event/training purposes and is therefore
recommended for all types of sports. This investigation is important to the field of
strength and conditioning, as the results will indicate whether AIS may aid in
performance in soccer players. And if so when necessary, AIS can be a great substitute to
dynamic stretching when space to warm-up is a factor.
Definition of Terms
Active Isolated Stretching:Active isolated stretching refers to actively taking a
limb through a full range of motion, holding for two seconds while
simultaneously contracting the opposing muscle group and then releasing while
allowing the limb to return to its starting position (Mattes, 1996).
Dynamic Stretching: Dynamic stretching refers to a controlled movement through
4
the active range of motion for one or more joints (Fletcher & Anness, 2007;
Fletcher & Jones, 2004).
Musculotendinous Unit: Musculotendinous unit refers to contractile component
(muscle fibers) in parallel with one elastic component(muscle membranes) and in
series with another elastic component (tendons) (Avela, Kyrolainen, & Komi,
1999).
Post Activation Pontentiation: Post activation pontentiation refers to the
temporary increase in the contractile ability of muscles after previous contraction
sessions (Sale, 2002).
Series Elastic Component: Series elastic component (SEC)refersto
passive elasticityderived from tendons when a muscle is stretched (Potach & Chu,
2000).
Sherrington's Law of Reciprocal Inhibition: Sherrington's law of
reciprocal inhibition refers to relaxation that occurs in the muscle opposing the
muscles experiencing the increase tension (Moore & Hutton, 1980).
Static Stretching: Static stretching refers to slowly applied stretch
torque to a muscle maintaining the muscle in a lengthened position from six and
up to sixty seconds(Mohr, Pink, Elsner, &Kvitne, 1998).
5
Stretching: Stretching refers to the act of applying tensile force to lengthen muscles and
connective tissue (Amiri-Khorasani, Sahebozamani, Tabrizi, &Yusof, 2010).
Delimitations
1. This study only used healthy Division 1 male collegiate soccer players.
2. The training occurred during the team’soff-season training period.
3. The training focused only on the lower body.
4. All of the players involved were classified as intermediate to advance in skill
level.
5. All athletes were free of injury to the lower body in the past six months.
Limitations
1. The subjects and research assistants were aware of the structure of warm-up
protocols and the test to be administered.
2. All subjects had administered some kind of stretching routine in the past four
months prior to participating in the study.
3. The results of this investigation were limited to healthy male collegiate soccer
players who had used some type of stretching modality for a minimum of four
months.
6
Assumptions
1. All subjects followed the specific instructions of refraining from any stretching or
fatiguing activity that would hinder their performance during testing.
2. All subjects accurately reported their physical activity and training status.
3. All subjects adhered to the stretching protocols to best of their abilities.
4. All subjects continued their regular physical activity during the study.
Hypotheses
1. There will be no significant increase in performance in the warm-up incorporating
active isolated stretches compared to the warm-up combined with dynamic
stretches.
2. There will be no significant increase in performance in the warm-up incorporating
dynamic stretches compared to the warm-up combined with active isolated
stretches.
7
Chapter 2
REVIEW OF LITERATURE
Soccer is a sport that relies predominantly on quick and explosive movements
such as kicking, jumping, dribbling, and sprinting (Ekblom, 1986;Little& Williams,
2005; Reilly, 1990). The first consideration for both the coach and athletes alike is to
begin training with an adequate warm-up. The warm-up is designed to increase motor
performance levels, increase body heat plus circulation, and physiological response
which may help avoid potential injury with the overall goal of improving performance
levels (Holcomb, 2000). However, the structure of the warm-up,specifically the type of
stretching modality included in training, has been debated over the past years (Bishop,
2003). The purpose of this study was to examine the effect of implementing AIS as part
of a warm-up on vertical jump performance in division on male soccer players.
Purpose of Stretching
Stretching in general has become a fundamental portion of the warm-up process
in athletics (Bandy, Irion, & Briggler, 1997; Cornwell, Nelson, & Sidaway, 2002; Davis,
Ashby, McCale, McQuain, & Wine, 2005; Faigenbaum, et al., 2006; Gribble, et al., 1998;
Witvrouw, Machieu, Danneels, & McNair, 2004). Stretching can be defined simply as
the act of executing a level of tensile force upon muscles and connective tissue in
attempts to lengthen them (Amiri-Khorasani, Sahebozamani, Tabrizi, & Yusof, 2010).
Traditionally, stretching is used as part of the warm-up process to increase flexibility or
pain-free range of motion (ROM) with the intent to allow for adequate performance
8
levels (Shellock, & Prentice, 1985; Smith, 1994) and/or to reduce the potential for injury
(Alter, 2004; Bixler & Jones, 1992; Ekstrand & Gillquist, 1983; Ekstrand, Gillquist,
Moller, Oberg, & Liljedahl, 1983; Garrett, 1990; Safran, Seaber, & Garrett, 1989).
According to Smith (1994), stretching benefits athletes in several ways. First, stretching
improves flexibility overtime which is crucial for explosive human movement in sports.
Stretching also impacts running economy, optimizes athletic performance, and increases
joint ROM. It also contributes to athletic function during rehabilitation treatment.
Finally, stretching may also reduce muscle soreness following a bout of tough or long
physical activity (Smith 1994). However, Needham, Morse, and Degens (2009) stated
that there is no concrete evidence to suggest that stretching prevents or reduces delayed
onset muscle soreness (DOMS).
Description of Static, Dynamic, Proprioceptive Neuromuscular Facilitation,
And Active Isolated Stretching
Static Stretching
According to several studies, static stretching as part of a warm-up routine has
been the most common stretch modality used in a multitude of sports (Church, Wiggins,
Moode, & Crist, 2001; Little & Williams, 2006; Taylor, Brooks, & Ryan, 1997; Young &
Behm, 2002; Young &Behm,2003). Static stretching is widely used because it is
considered easy and safe (Woolstenhulme, Griffiths, Woolstenhulme, & Parcell, 2006;
Yamaguchi & Ishii, 2005). This type of stretching modality requires one to take a muscle
to its end range and maintain the position for six and up to sixty seconds in duration
(Bandy & Irion, 1994; Bandy, Irion, & Briggler, 1997; Davis, et al., 2005). Smith (1994)
9
stated that with the slow build-up in tension caused by static stretching, the inverse
stretch reflex is called upon; resulting in induced relaxation in the muscle which allows
forcontinued stretching. Also, according to Beaulieu (1981), static stretching has no
association with injury, and is believed to be the most effective method of stretching.
Dynamic Stretching
Dynamic stretching is a functional based stretching exercise that employs sportspecific movement patterns geared to prepare the body for activity (Mann & Jones,
1995). This stretching modality takes a limb through a fullrange of motion by
contracting the agonist muscle while allowing the antagonist muscle to release/relax and
be stretched (Murphy, 1994; Yamaguchi & Ishi, 2005). Dynamic stretching has
demonstrated the potential to elevate "core" body temperature. It also enhances motor
unit excitability, thus allowing a further ability for power production (Faigenbaum et al.,
2006). Previous research has suggested that executing dynamic exercises at a moderate
to high intensity level before practicing a sport activity can also increase performance by
activating neuromuscular functions such as postactivation potentiation (Burkett, Phillips,
& Ziuratis, 2005; Faigenbaum et al., 2006; Guillich & Schmidtbleichher, 1996; Mcneal &
Sands, 2003; Thompson, Kackley, Palumbo, & Faigenbaum, 2007). Postactivation
potentiation can be defined as a temporary increase in the contractile ability of muscles
after previous contraction sessions (Sale, 2002). According to Gelen (2010), hops, skips,
arm swings, leg swings, and jumps which stress both the upper and lower extremities, are
considered the heart of the dynamic warm-up exercises. Also, dynamic warm-up
10
exercises can include plyometric exercises, heavy-load resistance exercises, and/or or
maximum voluntary contractions (MVC).
Proproceptive Neuromuscular Facilitation Stretching
Proprioceptive neuromuscular facilitation was described by Knott and Voss
(1968) as a technique that applies the concepts of reflex activation and inhibition.
Generally, the muscle is taken to its full lengthen position, then simultaneously one
actively contracts against manual resistance so the muscle can relax through selfinhibition;then it is stretched into a new available end range. This procedure, best known
as the contract-relax method, is commonly used when treating tight muscles. It is
repeated a number of times per limb, each time increasing the range of movement by
stretching the muscle into its new available range of motion.
Active Isolated Stretching
Active isolated stretching (AIS), termed the "Mattes method” is a unique method
of stretching (Mattes, 1996). This stretching modality is unique as it requires one to
activate or contract an opposing muscle (agonist) which in turn allows theopposite
muscle (antagonist) to release or relax via a neurological response. This neurological
responsecan be described simply as Sherrington's Law of reciprocal inhibition (Moore &
Hutton, 1980). According to Mattes, the simple use of a two-second stretch hold reduces
the potential of disturbing the Golgi Tendon Organs and muscle spindles which in turn
avoids the reflexive contraction of the antagonist that reduces the stretch potential of the
muscle one is attempting to stretch (Kochno, 2002). Therefore, since the muscle one is
11
targeting (antagonist) is forced to relax while it’s opposite (agonist) is contracted or
activated, the targeted muscle becomes an easier candidate for elongation. Mattes has
also stated that AIS can have a huge, immediate impact on human movement by
addressing circulatory, neuromuscular, and the myofascial systems. In fact, use of active
isolated stretching over time is believed to improve overall flexibility; and may prevent
acute and repetitive chronic stress injuries (Kochno, 2002).
The Effects of Stretching on Power Development
Static stretching pre-event has been thought to prevent injury and enhanceathletic
performance. However, over the years numerous studies have investigated the use of
static stretching on athletic performance only to find contradicting results (Sayers, Farley,
Fuller, Jubenville, & Caputo, 2008). There has been evidence to suggest that the use of
static stretching may actually decrease performance of movements requiring maximal
force production (Bacurau, et al., 2009; Behm, Button, & Butt, 2001; Cornwell, &
Kokkonen, 2001; Cornwell, Nelson, Heise, & Sidaway, 2001; Cramer, et al., 2004;
Cramer, et al., 2005; Cramer, Housh, Coburn, Beck, & Johnson, 2006; Curry,
Chengkalath, Couch, Romance, & Manns, 2009; Evetovich, Nauman, Conley, & Todd,
2003; Faigenbaum, Bellucci, Bernieri, Bakker, & Hoornes, 2005; Holt & Lambourne,
2008; Kokkonen & Nelson, 1998; McNeal & Sands, 2003; Nelson, Guillory, Cornwell,
Kokkonen, 2001; Nelson, Kokkonen, & Arnall, 2005; Samuel, Holcomb, Guadagnoli,
Rubley, & Wallmann, 2008;Young & Elliot, 2001; Yamaguchi & Ishii, 2005;
Yamaguchi, Ishii, Yamanaka, & Yasuda, 2006). In a recent study of twenty-seven male
12
soccer players, vertical jump heights were significantly greater in the active warm-up and
dynamic stretching groups when compared to the static stretching group (Fletcher &
Monte-Colombo, 2010). Also, according to Needham (2009), the decrements in strength
and explosive power following static stretching can remain for 15 minutes and up to 2
hours.
Most studies have come to the consensusthat the decreases in performance caused
by static stretching is due to the fact that it softens the musculotendinous unit (MTU) and
decreases muscle stiffness. The decrease in MTU stiffness causes acute neural inhibition
and decreases the ability to produce force and speed thereby leading to reductions in
power production in the muscles (Avela, Kyrolainen, & Komi, 1999; Knudson, Bennett,
Corn, Leick, & Smith, 2001; Nelson, Driscoll, Landin, Young, & Schexnayder, 2005;
Rosenbaum & Henning, 1995). Strength, power and speed are important attributes in a
sport like soccer. Causing a reduction in any of these attributes by the use of static
stretching negatively impacts performance and is why more people are turning their focus
more to the use of dynamic stretching (Fletcher & Monte-Colombo, 2010).
Previous research has demonstrated that dynamic stretching has just the opposite
effect of static stretching. It has been associated by numerous studies with improvements
in short-term high-intensity muscular performance (Faigenbaum, et al., 2005; Holt &
Lambourne, 2008; Little &Williams, 2006; Manoel, Love, Danoff, & Miller, 2008;
Pearce, Kidgell, Zois, & Carlson, 2009; Mcmillian & Moore, 2006). In the study by
Faigenbaum, McFarland, Schwerdtman, Ratamess, Kang, and Hoffman (2006), eighteen
13
healthy active females had significantly greater vertical jumps after moderate-intensity to
high-intensity dynamic stretches when compared to the static stretching group. The
dynamic group was said to have performed better due to dynamic stretching itself. The
researchers agreed dynamic stretching was more appropriate for warm-up purposes
because it is designed to prepare the athlete optimally for competition.
Recent studies conducted on the acute effects of proprioceptive neuromuscular
facilitation (PNF) have shown that this stretching technique may result in a significant
reduction or no change on jump performance and power output (Bradley, Olsen, &Portas,
2007; Church,Wiggins, Moode, & Crist, 2001; Knudson, Bennett, Corn, Leick, & Smith,
2001; Little & Williams, 2006; Power, Behm, Cahill, Carroll, & Young, 2004;
Wallmann, Mercer, & McWhorter, 2005; Unick, Keifer, Cheeseman, & Feeney,
2005;Young & Behm, 2003; Yuktasir & Kaya, 2009). In a recent study of ten
recreationally active females and nine recreationally active males, proprioceptive
neuromuscular facilitation (PNF) stretching caused decrements in power during poststretching when compared to pre-stretching (Marek, et al., 2005). Some studies may
have concluded that the reductions in power after a session of PNFstretching may have
been attributed by the level of stress and/or fatigue placed upon the muscles do to PNF
stretching itself (Church, Wiggins, Moode, & Crist, 2001; Young & Elliott, 2001).
The Effects of Stretching on Sprint Performance
A study by Nelson, Driscoll, Landin, Young, and Schexnayder, (2005) found that
static stretching during the warm-up phase had a negative impact on 20-m sprint
performance. Sprint performance was reduced after static stretching, and stretching the
14
muscles in one leg had the same negative effect as stretching both legs when compared to
the no-stretch group suggesting a central nervous system (CNS) mechanism. The
investigators of this study also concluded that the performance reductions may have been
associated with reduced stiffness of the musculotendinous unit. In another study by
Fletcher and Jones (2004) using 97 male rugby union players, a similar relationship
between static stretching and sprint performance was found. They also agreed
performance levels were negatively affected dueto reduced stiffness of the
musculotendinous unit. The investigators noted that static stretching changes tendon
structure (tightness) resulting inan increased compliance of the tendon. As a result,
lowered capability of force production and delayed muscle activationoccurs. Shorten
(1987) reported that the amount of elastic energy that can be stored in the
musculotendinous unit is a function of stiffness. Because static stretching reduces the
stiffness of the musculotendinous unit, less elastic energy can then be retained and used
after a session of static stretching (Potach & Chu, 2000). Also neurologically, it has been
suggested that stretching may cause a decrease in neural transmission from CNS to the
muscle, a phenomenon knownas neural inhibition (Kubo, Kanehisa, Hawakami, &
Fukunaga, 2001; Nelson, Driscoll, Landin, Young, & Schexnayder, 2005; Rosenbaum &
Henning, 1995).
Similarly, protocols involving static stretching have been compared to dynamic
stretching. Little and Williams (2006) conducted a study using 18 professional soccer
players and engaged them in dynamic, static, or no-stretch warm-up. On a 10-m standing
acceleration, they found that a dynamic warm-up,but not the static warm-up provided an
15
improvement in performance. Gelen (2010) stated that dynamic exercises performed
during warm-up process may increase explosive-power production increasing
neuromuscular functionality which aids in sprint performance. Thus, dynamic stretching
may elicit postactivation potentiation (PAP) known as a temporary increased contractile
ability of muscles after previous contraction and may contribute to sprint performance
(Sale, 2002).
The Effects of Stretching on Agility
Additional research has focused on the effects of stretching on agility
performance. The study by Little and Williams (2006) tested the effects of dynamic,
static, and no-stretch on professional soccer players agility capabilities. The dynamic
stretch protocol produced greater agility performance than both the no-stretch protocol
and the static stretch protocol. Amiri-Khorasani, Sahebozamani, Tabrizi, and Yusof
(2010)also examined static, dynamic, combined stretch (SS+DS) and no-stretch on agility
performance. Their results demonstrated that static stretching presented slower times in
agility performance compared to dynamic stretching as well. The authors concluded that
dynamic stretching during a warm-up was most effective for preparation of agility
performance. Another study done on the effects of stretching on agility using thirty
Military cadets (Mcmillian, Moore, Hatler, & Taylor, 2006) also found that static
stretching pre-event revealed worse times as opposed to dynamic stretching. The authors
concluded that the reasons for improvements in performance associated with dynamic
warm-up are reasons cited by Bishop (2003). Bishop (2003) stated that dynamic stretch
warm-ups improve short-term performance and raises core temperature. Also, decrease
16
stiffness of the muscles and joints, increase transmission rate of nerve impulses, and
changes in the force-velocity relationship can occur. Finally, improved glycolysis plus
high-energy phosphate degradation potential is also made possible by dynamic stretching.
Summary
Previous research clearly finds dynamic stretching to be superior to other
stretching modalities in terms of its effecton power, sprint, and agility performance. Yet,
no research has looked at the effects of combining active isolated stretching (AIS) as part
of the warm-up. Additionally, no research has been presented on the effect AIS has on
power, agility, and/or sprint performance in any given sport. Based on the effects of
other stretching methods used and their effect on power, a study is warranted to
investigate whether the use of AIS as part of a warm-up will provide a similar or an even
better effect on power performance when compared to other stretching modalities. The
purpose of this study was to examine the effect of implementing AIS as part of a warmupon vertical jump performance in division one male soccer players.
17
Chapter 3
METHODS
The purpose of this study was to examine the effect of implementing AIS as part
of a warm-upon vertical jump performance in division on male soccer players.
Assessment of the athletes took place in terms of power (vertical jump).
Subjects
The subjects used in this study were 18 volunteer soccer players from the
Sacramento State University men's soccer team. The athletes were transitioning into their
off-season training cycle. The athlete’s age ranged from 18 to 22 years old. All of the
athletes that were involved in this study were skilled position players. The athletes used
for this study were forwards, midfielders, defenders, and goalkeepers. All subjectswere
free from injury and were experienced in training and competed for at least one year at
the collegiate level. The University’s Review Board approved the research and all
subjects read and signed an informed consent and health questionnaire form before
participation.
Research Design
This study was completed using a between-groups design to investigate the
effects of Dynamic (DS), vs. Active Isolated Stretching (AIS) on vertical jump
performance in college soccer players after a general warm-up. Soccer players conducted
two different warm-up protocols on two non-consecutive test days. The eighteen subjects
18
were placed in one of two groups at random (Group1: N=9, Group2: N=9). The two
warm-up protocols were applied at random between the groups. Each test day would be
conducted more than 24 hours after a match or hard physical training in attempts to
minimize the fatiguing effects from previous exercise. All of the athletes completed both
of the warm-up protocols within a fifteen-day time span. The warm-up protocols differed
only by the mode of stretching method used. The exercises used in the warm-up
wereidentical in nature. There were two treatment groups, one of which received
dynamic stretching and the other active isolated stretching. Subjects for both groups
were asked to perform a standardized self-paced five-minute jog around a flat track.
Then they rested for two minutes. Next, the subjects underwent one of the stretching
protocols. After the stretch protocol had been conducted, another rest-interval of two
minutes was allowed. Finally, the soccer players complete three attempts back to back on
the performance test. The performance test consisted of a vertical jump.
The power test consisted of a vertical jump. The vertical jump is a
countermovement jump where the athletes are instructed to jump straight up vertically. It
is an explosive movement that requires full and complete ankle, hip, and knee extension.
Procedures
Before data collection, all subjects participated in an introductory mini-lecture to
become familiar with the structure of the entire testing procedures. All subjects would
report to the football field for testing on two non-consecutive days. All subjects
performed the two randomized warm-up conditions, with at least 24hr and no more than
19
72hr between sessions. The participants were asked to refrain from stretching and
fatiguing activity other than those they were already performing at team practice and
exercise sessions. Participants were also asked to refrain from caffeine intake on each
testing day and to avoid food consumption in the two hours prior to testing. Additionally,
sessions were performed at the same time ofday (afternoon) to avoid any diurnal
variations. Finally, the participants were asked to be consistent in their pre-experiment
activities onthose days.
The DS protocol consisted of a five-minute-self-paced jog followed by a series of
lower body dynamic stretches. The exercises chosen for this study were the
following:form run, heel-to-butt walk, knee-tuck walk, knee cradle walk, walk-to lunge,
"Spiderman" hip flexor/hamstring stretch, and carioca. These particular stretches are
ordinarily used by soccer players and are very familiar. These movements were carried
out covering a 15 yard span (a walk back recovery was employed between exercise sets
to minimize any chances of fatigue). The athlete’s performed each exercise twice,
meaning walking forward 15 yards, and coming back 15 yards. The duration of the entire
dynamic warm-up routine was approximately 10 minutes. These stretches should be
considered active dynamic stretches since the movements were carried out while jogging
(Fletcher & Jones, 2004).
The AIS protocol consisted of a five-minute-self-paced jog followed also by a
series of lower body AIS stretches. Each stretch exercise was demonstrated to the group
once, and then each stretch exercise was performed with the group. A verbal signal to
begin was given; following two seconds a "release," signal was given to indicate the
20
point where one returns the limb to starting position. The exercises chosen were the
following: quadriceps-stretch (in the prone position one pulls a rope attached to the front
of the foot), hamstring-stretch (in the supine position one pulls a rope attached to the
bottom of the foot), hip-flexor stretch (in the kneeling position oneapplies a forward lean
at the hip), abductor-stretch (in the supine position one pulls a rope attached to the ankle
away from the body laterally), adductor-stretch (in the supine position one pulls a rope
attached to the ankle across the body medially), and the gluteus maximus-stretch (in the
prone position with ones' hands a pull behind the knee is applied); all of these exercises
were designed by Aaron Mattes (1996). All the stretches require that the athletes provide
a two-second stretch to the muscle being targeted (antagonist) while simultaneously
contracting the opposing muscle (agonist) (Mattes, 1996; Kochno, 2002). The athletes
performed 10 repetitions per leg, repeated for all of the stretches. All AIS stretches were
performed while lying stationary on the ground. These particular stretches were also
designed to stretch the same muscles as the DS protocol.
Instrumentation
The power portion of the experimental protocol involved the vertical jump test.
The vertical jump was tested using a Vertex vertical jump tester.
Data Collection
The data for this study was collected upon completion of each test. Each athlete
was responsible for having the researcher present to observe the actual attempts that the
21
athletes would take. The mean of the three trials and the mean of the groups were
recorded and were used for this study.
Statistical Analysis
An independent t-test (SPSS) was used to test for between group differences for
both the dynamic stretch group and the AIS group. The independent variables in this
study were the dynamic and AIS stretch groups. The dependent variable in this study
was vertical jump heights.The level of significance was set at p<.05.
22
Chapter 4
RESULTS
Initially, 24 subjects were recruited for this study. Due to injury and/or illness,
only 18 players participated in the study. Subjects in the present study were male, and of
the same age range (18-22). All had previous soccer playing experience through club,
high school, and some collegiate experience. Each subject was randomly placed into one
of two stretching groups, which were, the dynamic stretch group, and the active isolated
stretch group.
Vertical Jump
In the vertical jump, the dynamic group averaged 24.23+ 3.09 inches while the
AIS group averaged 24.35 + 3.22 inches. An independent samples t-test revealed no
significant difference between the groups in the vertical jump (t = -.116, p = .908).
Table 1.
Mean and SD of performance measures for test
conditions (n=18).*
Condition
Countermovement jump
(inches)
DS
24.23 + 3.09*
AIS
24.35 +3.24*
Note. DS=dynamic warm-up; AIS=active isolated warm-up.
23
Hypotheses
1. There will be no significant increase in performance in the warm-up incorporating
active isolated stretches compared to the warm-up combined with dynamic
stretches. This hypothesis was supported by the results of the data.
2. There will be no significant increase in performance in the warm-up incorporating
dynamic stretches compared to the warm-up combined with active isolated
stretches. This hypothesis was supported by the results of the data.
Summary
There was no significant difference (P<.05) found in the vertical jump between
the groups. Results for this study led to the acceptance of both hypotheses one and two,
which stated that there would be no significant difference in vertical jump performance
between the groups. Results showed that AIS stretching did not elicit improvements in
vertical jump performance any further than dynamic stretching.
24
Chapter 5
DISCUSSION
The purpose of this study was to examine the effect of implementing AIS as part
of a warm-upon vertical jump performance in division onemale soccer players. This
study examined a comparison between a new stretching modality versus a traditional
stretching modality after a warm-up on vertical jump performance. The new stretching
modality was active isolated stretching, and the traditional stretching modality was
dynamic stretching.
Although no previous studies have reported the effect AIS on power, previous
studies have found dynamic stretching to be superior to other stretch modalities on power
(Fletcher & Jones, 2004; Fletcher & Anness, 2007; Little & Williams, 2006; Mcmillan et
al., 2006; Yamaguchi & Ishii, 2005). However, results from this study did show an
almost similar performance outcome when comparing AIS to dynamic stretching.
Vertical Jump
Results from this study showed neither significant improvements nor decrements
in vertical jump performance between groups. Previous studies have shown significant
decrements in performance using static, ballistic, and/or PNF stretching when compared
to dynamic stretching (Behm, Button, & Butt, 2001; Cornwell, Nelson, & Sidaway, 2002;
Fletcher & Anness, 2007; Nelson, Allen, Cornewell, & Kokkonen, 2001; Nelson &
Kokkonen, 2005). Thus, it was interesting to find no difference between AIS and DS.
25
Recommendations for Future Studies
Although many studies exist havingexamined the effects of dynamic stretching on
performance, lack of sufficient evidence on the effects of AIS exist. Therefore, more
research is warranted to determine exactly if AIS can in fact improve performance.
Future studies may test AIS on other performance measures such as agility, speed, and/or
strength, or compare AIS to other modalities like static or PNF stretching on such
performance measures.
Another future direction for researchers to pursue would be to test the effect of
using AIS on another type of sport. Also, the majority of studies discussed in this paper
used male college or professional athletes. A study using female athletes would help
determine if any differences may exist between male and female athletes when using
AIS.Since the team used in this study was new to AIS, the next step for researchers
would also be to study the effects of AIS on athletes who are completely familiar and/or
already incorporate AIS as part of their training regimen.
Other factors that can be tested by future research are the number of assessment
days used and number of subjects used. Unlike this study, most studies had an average of
three tests days on three non-consecutive days (Amiri-Khorasani, Abu-Osman, &Yusof,
2011; Faigenbaum et al., 2006; Little & Williams, 2006; Yamaguchi & Ishii, 2005;
Yamaguchi, Ishii, Yamanaka, & Yasuda, 2006). Also, most of the studies discussed in
this paper had an average of 21 subjects used which is more than this study was allowed.
26
Further studies could manipulate some of these factors and potentially reveal different
results.
Conclusion
Past studies have come to the agreement that DS is the best and most appropriate
stretch method for warm-up purposes. Aside from the DS group results in this study
however, the AIS group did not result in an increase in performance nor a decrease any
further than the DS group. One can then conclude that when if necessary, AIS may be a
substitute to DS during a warm-up. If space is not available for warming-up for example,
one can simply locate a spot on the ground and begin a series of AIS stretches before
training or competition. Decreasing performance by incorporating static or PNF
stretching with the warm-up is out of the question. Therefore, AIS may be included as
part of the warm-up without worry of compromising power performance.
27
APPENDIX A
Consent to Participate in Research
You are being asked to participate in research which will be conducted by Sergio
Pena, a graduate student in Kinesiologyat California State University, Sacramento.
The purpose of this study will be to examine the effects of implementing active
isolated stretching as part of a warm-up on vertical jump performance in collegiate
soccer players.
You will be asked to complete a questionnaire about your health history on
whether you were subject to any recent musculoskeletal injury. If you have nothing in
your health history that would exclude you then you may participate in this study.
You will be asked to participate in an introductory session and then in two testing
sessions on two nonconsecutive days. The total time commitment for participating in
this study is approximately 30:00 minutes. During the two testing sessions you will
be asked to perform a five-minute self-paced jog around a flat track. You will be
allowed two minutes to recover. Then you will participate in one stretching routine
on one day and the other stretching routine on the following day. The first routine
will consist of undergoing a series of dynamic stretches to the lower body that are
commonly used in training. The second routine will consist of undergoing a series of
active isolated stretches to the lower body. All of the routines will be run by the
researcher of this study. You will rest another two minutes after stretching and then
participate in a vertical jump test.
There will be minimal-risk to you as a participant in this study. The tests and
stretching protocols involved in this study should not increase your risk of injury
beyond those encountered in normal activities of daily living. However, there is some
risk associated with these testing and stretching techniques, such as rapid breathing,
increased heart rate, increased blood pressure, sweating, some muscular discomfort,
and some fatigue mostly during the testing procedures for this study.
You may gain additional knowledge on another form of stretching modality that
may be useful to an athlete of your sport. It is hoped that the results of the study will
be beneficial for both Coaches and Athletes alike who may have considered or
already use this type of stretching modality. The results will provide an answer as to
whether active isolated stretching is effective or not in positively aiding in
performance.
Your responses on the questionnaires will be kept confidential. A pseudonym
will be used when collecting all data. Your test results will be kept separately from
your health history & informed consent document. All documents will be kept stored
away in a computer only I, the researcher can see. Any and all results will be
28
reported in aggregate form only and without the release of information that could be
used to identify you.
You will not receive any compensation for participating in this study.
If you have any questions about this research, you may contact Sergio Pena at
(xxx) xxx-xxxx or by e-mail xxxxxxx@netzero.net.
Your participation in this research is entirely voluntary. You have the right to
discontinue participation in this research project at any time without penalty or loss of
rights to which you are otherwise entitled. If you encounter a research related injury
you will be referred to the Student Health Center at (916) 278-6461. Your signature
below indicates that you have read this page, had any and all of your questions
regarding this research answered and agree to participate voluntarily in the research.
Signature of Participant
Date
29
APPENDIX B
Physical Activity Readiness Questionnaire (PAR-Q)
Please take a second to complete this questionnaire with full honesty in attempts to
ensure your full safety while participating in this study.
(Please circle answer)
1. Have you ever fallen over or ever lost consciousness as a result of dizziness
during or after exercise? Yes No
2. Has a doctor ever said that you have high blood pressure? Yes No
3. Has a doctor ever said that you have a heart condition and recommended only
medically supervised physical activity? Yes No
4. Do you ever experience chest pain or an irregular heart-beat as a result of
exercise?
Yes No
5. Do you have a bone or joint problem that can be aggravated by the proposed
physical activity? Yes No
6. Do you suffer at all from lower back pain, i.e., chronic pain or associated
numbness in the lower extremity? Yes No
7. Is there a good physical reason, not mentioned here, as to why you should not
participate in the proposed physical activity? Yes No
8. Have you had any surgery as a result of an injury to the back or lower extremity
(ankle, knee, hip) in the last 6 months? Yes No
If YES, please specify
9. Have you had a recent (within the last 6 months) injury to the lower body that has
received medical attention? Yes No
I certify that the above statements are true and correct. I understand that a Doctor's
note may be requested. If a note is requested, I should not proceed with this
experiment until the note is received.
Signature of Participant
Date
30
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