Effects of Flexibility Training on Agility Performance
Group # 2
Cassandra Corlyon
Aly Gillis
Aaron McDonald
Shannon Robichaud
Dr. Sasho Mackenzie
Hkin 396: Quantitative Research Methods
Department of Human Kinetics
St. Francis Xavier University
Monday, April 7, 2014
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INTRODUCTION
Most high-level performance sports involve a high level of agility. Athletes with an
increasing intensity of competition level will incorporate agility-training techniques to improve
their level of performance. Agility is highly dependent on coordination and movement control.
Apart from coordination and control, there are a number of factors that affect agility such as
strength, speed, mobility of joints, dynamic balance, power, flexibility, and level of energy
resources (Sprois et al., 2010). Agility has been defined as the ability to accurately and rapidly
change direction, make quick stops; and the ability perform fast, smooth, efficient and repetitive
movements. Skills contributing to an athlete’s ability to move quickly include: technical
footwork, movement speed, decision-making, and accuracy of movement (Galpin et al., 2008).
Considering the importance of agility in many sports such as soccer, football, basketball, and
racket sports, it’s important to determine the components of agility. Assessments of these
components can be used to train and ultimately improve agility performance in athletes.
Traditionally, agility tests have been performed to test rapid acceleration and change of
direction. There are a variety of agility tests to account for the many components of agility. For
example, the T-test, Balsom agility test, zigzag test and 505 agility test, are all used to determine
speed with directional change (Jordan et al., 2012). Directional change includes forward
sprinting, backpedaling and side shuffling. Another test, the Illinois agility test, is used to
determine the ability to accelerate, decelerate, turn in different directions, and run at different
angles (Asadi, 2013). In contrast, the force plate agility test determines quickness and power by
measuring ground contact time while hopping this test requires an athlete to remain balanced in
order to shift their body weight in several different directions (Miller et al., 2006). Lastly, the
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physical agility test is used to incorporate the strength aspect of agility performance, in which
case many resistance performances will be measured. A common form of this test is the
countermovement jump (CMJ) where participants perform an unconstrained vertical jump from a
standing upright position that includes the initial counter-movement (Sporis et al., 2010). By
observation of the plethora of reliable testing procedures on agility, and the incongruous
definitions provided in previous research articles, it’s reasonable to consider agility a multidimensional skill, encompassing more than one bio-motor ability.
Considering the many aspects of agility, there are many training techniques to improve
agility performance. Coaches often incorporate ladder, and pylon drills within the warm-ups of
practices, to enhance athletes’ reaction time, and their ability to change direction. Athletes’
training can include strength training regimes, and plyometric training to improve the peak
power aspect of agility performance. Additionally, computerized agility training can be used to
enhance reaction time and quick decision-making.
A noteworthy component of agility is speed. Maximum speed is the maximal velocity at
which a player can sprint (Little & Williams., 2005). If an athlete can improve their speed by
participating in specific speed drills, then they can improve their overall agility performance. In
Galpin’s et al. (2008) study, the operational definition of agility included movements that
comprised of three components: quickness (movement speed), choice reaction, and change of
direction. According to Galpin et al. (2008), four weeks of foot-speed training improved the
agility performance of non-agility trained, as well as active men and women (foot speed (p =
0.004), Reaction time (p = 0.011), and Change of Direction (p =0.049) )
In a six-week study by Bloomfield et al (2007), two methodologies for speed and agility
conditioning were compared. The first method consisted of specific SAQ (speed, agility,
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quickness) conditioning, whereas in the second method participants played small sided soccer
games. The results of the study showed that the SAQ exercises appeared to be the best and
superior method for improving speed and agility performance (p<0.01).
Plyometric training involves the use of high speed power movements, such as jumping
variations and throwing that involve an eccentric movement followed by a fast concentric
movement (Baechle and Earle, 2000). Miller et al. (2006) found that if participants followed a
six-week plyometric program they were able to significantly improve their times with the T-test
agility measure(-0.62±0.24s), the Illinois Agility test(-0.50 ± 0.32s), and a force plate agility test
-26.37 ± 21.89 msec). Another six-week program involving standing long jumps, depth jumps,
and vertical jumps has also been determined to be effective in increasing young basketball
player’s agility as well as their vertical jump and standing long jump, both related to agility
(Asadi et al., 2013).
Resistance training on agility was investigated by Johnson, Burns, & Azevedo (2012).
They had two groups of high school football complete six-weeks of either traditional or circuit
training and, among other measures, had the participants complete an agility pro test
(participants sprinted five yards, turned around, sprinting another ten yards, then turned around
and sprinted five yards to the starting line). They found that neither a traditional block training
routine nor a circuit training routine significantly increased scores on agility (Johnson et al.,
2012). However, Negrete and Brophy (2000) did find that strength did play a role in agility.
They had participant’s complete three isokinetic leg strength tests, single leg hops, vertical
jumps, and an agility test. Negrete and Brophy (2000) were able to find a strong positive
correlation between leg strength and both kinds of jumps (single leg hop: r = 0.73, vertical jump:
r = 0.56), as well as a strong negative correlation between leg strength and agility test times (r
Effects of Flexibility on Agility Performance
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ranged from -.47 to -.59, i.e. those that had stronger legs performed better). The research done on
strength and agility seems to be inconclusive at this point in time.
Flexibility is most often overlooked as a component of agility. Consequently, there is a
lack of confident research on the agility-flexibility relationship, and performance gains from
flexibility training alone. As previously discussed, speed, resistance, and plyometric training are
components of agility that have been researched inducing positive gains in agility performance.
However, flexibility is a component of agility that has potential for additional performance
benefits.
An improvement in flexibility is typically enhanced by dynamic, static, and/or
proprioceptive neuromuscular facilitation (PNF) stretching. The general advantage of a preexercise stretch is to increase blood flow and body temperature, and to enhance free coordinated
movement. This relates directly to the concept of agility, which by definition requires mobility
throughout the joints. However, the relationship between flexibility training and agility has not
been clearly defined. McMillian et al. (2006) conducted a study investigating the acute effect of
dynamic versus static stretching on improving agility and power. Their findings show that
dynamic stretching lead to modest enhancements on agility and power, relative to static
stretching and a control group (p < 0.01). A thorough study by Chaouchi et al. (2010)
investigated static, and dynamic stretching, or a combination thereof. This study revealed that
there were no significant agility impairments or enhancements done by either acute static or
dynamic stretching. Further research presented by Jordan et al. (2012) explored the effects of
PNF stretching, compared to static stretching, with the hypothesis that acute PNF stretching
could increase agility due to increased stiffness in musculotendinous unit (MTU) thus reduced
contraction time, and greater mechanical efficiency (Rees et al., 2007). Their findings report no
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significant evidence to support their hypothesis; however they did discover that PNF and static
stretching showed no negative effects on agility in male soccer players (Jordan et al., 2012).
With the current discrepancy in regards to flexibility and performance, further research is
required.
There is a lack of confident research done on the effects of flexibility training on agility.
Stretching techniques are commonly used in both athletic and clinical settings to enhance both
active and passive ranges of motion to optimize motor performance. Seeing that the definition of
agility is a quick and accurate change in direction, with mobility through the joints, and optimal
coordination, one could hypothesize that a flexibility training regime could improve agility
performance tests. Agility is a critical factor in many team and individual sports, which is why
further research is important. As outlined above, the research conducted in this subject area has
only explored the acute effects of a variety of stretching techniques by incorporating dynamic,
static, or PNF stretches during warm-up, prior to a series of controlled and tested fitness
conditions. The purpose of the study was to observe the effects of chronic flexibility training and
to determine if proprioceptive neuromuscular facilitation (PNF), as compared to static and
dynamic stretching shows improvement in agility performance. It was hypothesized that PNF
stretching would result in the greatest improvements in agility performance.
METHODS
Experimental Approach to the Problem
A 8-week training program, which focused on flexibility training in three different groups
required participants to stretch five days per week. There was also a control group that did not
perform any stretching training. There were two independent variables, group assignment, and
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time. Group assignment included static stretching (SS), dynamic stretching (DS), proprioceptive
neuromuscular facilitation stretching (PNFS), and a control group (NS). Time contained two
levels (pre-test, post-test). The dependent variable was the participants’ score on the Illinois
agility test.
Orientation
Subjects attended differentiated group orientation sessions providing instructions for
static, dynamic, or proprioceptive neuromuscular facilitation (PNF) stretching exercises. In this
orientation session, demonstrations of each stretch were performed with proper technique and
specific stretching instructions (duration, frequency). They were also asked to perform the
Illinois agility test during orientation, purely for familiarization with the testing procedures;
results were not recorded. To ensure proper technique and maximum flexibility enhancements,
participants were given feedback on their execution of stretching exercises and test performance.
Participants
The participants in this study included a total of 120 male and female university students
pursuing degrees in the department of Human Kinetics in their third or fourth year of study from
St. Francis Xavier University. All participants who volunteered were 20 to 23 years of age, and
were actively engaged in physical activity approximately 250 minutes a week. Physical activities
included exercising at the university’s wellness centre, participating in skill activities for classes,
and extracurricular involvement in athletics. Generally, their everyday physical activity came
from participating in aerobic, anaerobic, and resistance training. Participants were selected from
within the department of Human Kinetics because of their in-depth knowledge of human
movement. Participants were screened for balance disorders, recent surgery on lower or upper
extremities, and injuries that could impair flexibility improvements or agility testing. Using
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Human Kinetics students, as well as screening participants, permits the assumption that all
participants had the physical and intellectual capacity to abide by an eight week prescribed
training program.
Procedure
The participants were randomly assigned to one of four groups. Each group had 30
participants (15 male, 15 female). The participants were administered a pre-agility test before
the eight week flexibility training period, and then a post-agility test after the eight week training
period. The test administered was specific to evaluation of agility performance. In this case, the
Illinois Agility Test (IAT) was used.
Performance Testing. The IAT consisted of a grid with a length of 10m and a width of
5m. The course was marked using pylons with four centre ones that made a vertical line that
divides the grid in half, which are 3.3m apart from each other, and four corner pylons marked
2.5m from the centre (Figure 4.0). The participant started the test when a whistle was blown.
Participants ran to the other side of the grid and back, then weaved through pylons (without
knocking them over), and then finished with running to the other side of the grid and back again.
The time was then recorded in seconds by volunteers in Human Kinetics department, who were
unaware of the participants’ group assignment during testing. This test was administered in the
gymnasium facilities at St. Francis Xavier University.
Treatment. All participants were instructed to continue regular daily physical activities
and not to change their fitness regimes in any way. Controlling this increased internal validity,
which increased the certainty that changes in agility test performance were related to the
independent variable (group assignment), and not due to changes uncontrolled by the study
design. Each stretching group was instructed to perform their stretches after they completed a
Effects of Flexibility on Agility Performance
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warm up of 5-10 minutes performed at 40-60% of VO2max (McMillan et al., 2006). They were
told to do perform the stretches five times a week (Monday-Friday), for a total of eight weeks.
Post exercise/physical activity was an opportune time because all of the muscles were equally
warmed up. The stretches performed include all body parts but focused mostly on the lower
body.
Dynamic
Dynamic stretching involves controlled movements through the range of motion that are
related to the activity about to be performed (Baechle and Earle, 2000). Stretches performed for
this group are:
Figure 1.1 Arm Circles- Move arm in a 360 degree rotation and do 10 in the forward direction
and then do 10 going in the reverse direction.
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Figure 1.2 Trunk Rotation- Keep feet planted and rotate trunk from side to side while
maintaining original feet position
Figure 1.3 Hip Rotation- Hold hands on hips and rotate hips in a clockwise direction completing
a full rotation
Figure 1.4 Front and Back Leg Swings- One leg at a time, perform flexion of the leg at the hip
and then extension of the leg. Keep leg straight ( slight knee flexion) at all times.
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Figure 1.5 Side to Side Leg Swings- One leg at a time, Keep leg straight ( slight knee flexion )
and adduct leg to cross the center of your body, then abduct leg and swing leg away from body.
Figure 1.6 Lunge- Keeping an upright torso position at all times, step out in front of you with
one leg then perform flexion at the knee ( close to 90 degree flexion- thigh to torso) , while other
foot stays planted.
These stretches are completed by three sets of 10 repetitions (10 for each leg for leg
swings and lunges) in a circuit fashion as seen in table 1.0.
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Table 1.0: Dynamic Stretching number of sets and repetitions performed in one training session.
Five sessions were completed each week.
Stretch
Sets
Time(s)
Arm Circles
Trunk rotations
Hip rotations
Front and back leg swings
Side-to-side legs swings
Half squat
Lunge
3
3
3
3
3
3
3
10
10
10
10 (for each side)
10 (for each side)
10
10
Static
Static stretching involves slowly moving the body or a limb into a specific position and
holding it until an uncomfortable but not painful exertion is felt. Stretches performed by this
group are:
Figure 2.1 Arm Across Chest- Move arm across your chest while your other arm holds in place.
Effects of Flexibility on Agility Performance
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Figure 2.2 Pectoral Stretch - Hold onto wall with one arm and then face opposite direction ,
keeping your arm straight ( slight flexion at elbow)
Figure 2.3 Seated Trunk Twist- Sitting on the ground, take arm and move it across your body to
the other side and twist torso facing the side that your arms are on.
Figure 2.4 Standing Quadriceps- Standing up, one leg at a time, perform flexion of your knee
and bring heel to touch gluteus and hold.
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Figure 2.5 Toe Touch- While maintaining just a slight flexion at the knee, reach down and touch
your toe or ground.
Figure 2.6 Seated Butterfly- While sitting on the ground, bring feet together and touch soles
together while pushing knees out to the side.
Figure 2.7 Laying Knee to Chest- While lying on your back, perform flexion at the knee and hip
and bring knee to your chest and hold.
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Figure 2.8 Standing Calf- While standing in a split squat position ( one leg in front of you, one
leg behind you) , perform flexion of the knee in the leg in front of you and keep the other leg
straight.
Participants performed three sets of 30 seconds (30s for each leg, arm, and direction) for
each stretch as seen in table 2.0.
Table 2.0: Static Stretching number of sets and time held in one training session. Five sessions
were completed each week. Participants rested for 15 seconds between sets.
Stretch
Sets
Time(s)
Arm across chest
Wall-assisted
horizontal
extension at shoulder
Seated trunk twist
Standing quadriceps
Seated butterfly
Laying knee to chest
Step calf
3
3
30
30
3
3
3
3
3
30
30
30
30
30
Proprioceptive Neuromuscular Facilitation
PNF stretching is usually done with a partner and involves a muscle activation
(contraction) followed by a passive static stretch (Baechle and Earle, 2000). Participants in this
group completed these PNF stretches with a partner:
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Figure 3.1 Laying Hamstring- Laying on your back, one leg at a time, perform flexion of leg at
hip and keep leg straight, then partner rests leg on shoulder and causes even more flexion
Figure 3.2 Laying Quadriceps - Laying on stomach, one leg at a time, perform flexion of knee
so heel touches gluteus (or comes close) , then partner holds foot that is being used.
Figure 3.3 Seated Groin- Perform seated butterfly stretch ( see above for directions) then have
partner kneel behind you or in front of you and press down on your knees with a hand on each
knee.
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Figure 3.4 Seated Calf- While sitting on the ground, one leg at a time, straighten leg and perform
dorsal flexion at the ankle while your partner holds your foot.
Figure 3.5 Kneeling Chest- While kneeling on the ground, put hands on back of your hand. Then
have partner grab your elbows, pulling them further behind you and stretching your chest.
These stretches were done in three activation and relaxation cycles for each stretch. The
activation portion of the cycle consisted of the participant contracting the muscle being stretched
as intense as they could for ten seconds then they would relax for twenty seconds (relaxation
portion of cycle) as seen in table 3.0.
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Table 3.0: PNF Stretching number of cycles repeated in one training session by each partner.
Stretch
Number of Cycles
Laying hamstrings
Laying quadriceps
Seated groin
Seated calf
Kneeling chest
3
3
3
3
3
Statistical Analyses
Repeated measures of analysis of variance (ANOVA) was used to assess the results.
Repeated measures (2 [test] x 4 [groups]) was used to measure the effects of the four stretching
protocols over an eight week training program. For post hoc analysis, Scheffe was administered
with a significance set at p<0.05.
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RESULTS
Subjects
All 120 subjects completed the 8 weeks of training with no subjects withdrawing from
the study and no participants were considered significant outliers.
Statistical Analysis
Descriptive statistics representing the performance on the dependent variable based on
training conditions are presented in Table 4.0. Using repeated measures (2 [Test] x 4 [Groups])
analysis of variance (ANOVA), it was determined that there was significance difference between
the four training condition groups on the dependent variable f(116)=7.67, p < .001. The results
were also practically meaningful as the partial eta squared was .165. Further analysis using the
post hoc test, Scheffe was administered for each interaction having a significance level set at p ≤
0.05. Scheffe’s revealed that there was a significant difference between the mean differences of
time in the PNF training condition compared to the control group (p=.001) as well as the static
stretching training condition (p=.004). This shows that participants in the PNF training condition
completed the Illinois agility posttest with the most improvement through the 8-week training
sessions. There was no significant difference found between the mean differences of time in the
dynamic stretching training condition compared to the control group (p=.068), the PNF training
condition (p=.586), or the static stretching training condition (p=.138). There was also no
significant difference found between the mean differences of time in the static stretching training
condition compared to the control group (P=.990). The post hoc test, Scheffe revealed that the
PNF training condition significantly improved from pretest time (19.0) to posttest time (16.6)
when compared to all other training conditions after an 8-week PNF flexibility training program.
Effects of Flexibility on Agility Performance
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With a decrease in time of completing the Illinois agility test of 2.4s this is significant enough to
state that PNF training overall improves agility performance.
Table 4.0 Mean (SD) Illinois agility test scores.
Training
Condition
Control
Dynamic
PNF
Static
Illinois Agility Test (s)
Pretest
18.7 (2.1)
18.7 (1.9)
19.0 (2.1)
18.8 (1.6)
Posttest
18.9 (2.2)
17.2 (2.3)
16.6 (2.7)
18.8 (2.3)
DISCUSSION
It was hypothesized that PNF stretching would produce the greatest results for increasing
agility in the participants. The results support the hypothesis, with the PNF stretching group
reducing their times on the IAT when comparing to the pre and posttests (-2.4s) and having mean
group scores that were significantly lower than the control and static groups. The dynamic
group’s time also decreased from pre to post-tests (-1.5s) but their mean group score were not
significantly lower than any other of the groups, meaning that the PNF stretching was most
effective. This may be due to PNF having one of the greatest abilities, through muscular
inhibition (Baechle and Earle, 2000), to increase joint mobility which is one of the factors of
agility (Sprois et al., 2010). Another reason is the training effect PNF stretching causes in
muscles which may cause them to recover faster.
In this study, a factor that was not controlled was the types of exercise programs people
were assigned during the eight weeks. A possible new direction for research would be matching
exercise program types and flexibility training types to see which combinations are most
effective. For example, compare the types of flexibility training when the participants are only
Effects of Flexibility on Agility Performance
21
doing plyometric programs. In future studies it would also be important to include more than
one measure in the testing procedures to ensure all aspects of agility are examined.
In conclusion, this study found evidence that PNF flexibility training was most effective
in increasing agility performance and it was significantly better than static and control
groups. Future research should focus on different exercise programs and the use of multiple tests.
Practical Application
Based on the present study and previous studies, PNF training should be implemented by
team conditioning coaches to gain further improvement in agility performance. As athletes with
an increasing intensity of competition level will be more likely incorporate agility-training
techniques to improve their level of performance. PNF stretching can also provide relaxation to
high performance athletes.
Acknowledgments
The authors wish to thank Group #1 member, Emma Gibson for fabricating the data of
the study in timely manner Further acknowledgments are extended to Dr. Sasha Mackenzie and
his Quantitative Research Methods class, for instruction and guidance throughout this process.
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