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Flexibility
The Ability to Take a
Lever System Through
a Range of Motion
and the Time It Takes
to Go Through a
Range of Motion
04/2012
d:\Faculty\Allsen\EXSC 468\Winning Edge\EXSC46804Flexibility
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I.
Flexibility—Read in Appendix: Should Athletes Stretch Before Exercise?, p. 251
A. Ability to take a joint-lever system through a full range of motion
B. Time it takes to go through a full range of motion
C. A flexibility program should never be used solely for a warm-up for other activities. It is a
conditioning regimen itself, like strength and endurance training
II.
Joint Lever System
A. Striated muscle tissue
1. Agonist
2. Antagonist
3. You can stretch a muscle 60% of its resting length when it is relaxed
B. Connective tissue
C. Skeletal tissue
III.
Reasons for Flexibility
A. Helps to avert injuries to joint capsules by preventing movements from tearing excessively or too
tight of ligamentous structures
B. Prevents antagonistic muscles from strain while being eccentrically stretched during ballistic
limb motion
C. Provides a greater range of motion in a joint, creating the potential for greater force development
1. Speed of running = stride length x stride frequency
a. An increase of 4 inches in stride length, with the same stride frequency, will reduce
time in the 100-yard dash by .5 second and reduce the time in 220-yard dash by 1.1
seconds
D. Increased range of motion permits the freedom of movement so critical to performance
IV.
Resistance to Flexibility
STRUCTURE
A. Joint capsule
B. Muscle and surrounding connective tissue
C. Tendon
D. Skin
V.
% OF TOTAL RESISTANCE
47
41
10
2
Types of Stretching
A. Phasic—fast, jerky, bobbing type of movement
B. Static—slow, sustained type of movement
1. PNF = proprioceptive—neuromuscular—facilitation
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VI.
Proprioception—sensory feedback concerning joint position, joint movement, where the body is in
space
A. Proprioceptors involved in a flexibility program
1. Muscle spindles
a. When stimulated causes a myotatic reflex which brings about motor unit contraction in
a muscle
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2.
Golgi tendon organs
a. When stimulated causes an inverse myotatic reflex which brings about motor unit
relaxation and total muscle relaxation
VII. Tension Threshold on Muscle to Stretch Selected Proprioceptors
A. Muscle spindle = 3 to 19 grams of tension
B. Golgi tendon organ = 100 grams of tension
VIII. Time to Achieve Force of Tension and Sensory Units Stimulated
SENSORY (AFFERENT) IMPULSE FREQUENCY
TIME TO ACHIEVE FORCE
A. 1 second (phasic)
100 per second (muscle spindle)
B. 6+ seconds (static)
40 per second (Golgi tendon organ)
IX.
Stretch Reflex and Flexibility
A. The stretch reflex has some very interesting qualities for muscle stretching in developing
flexibility or warming-up athletes. There is very good evidence that the stretch reflex has two
components, one of which is the result of phasic (jerky) stretching and the other result of static
(maintained) stretch. The phasic response seems to be faster and stronger, and typified by
synchronous discharges of the spindles, whereas the static response is slower and weaker, and
typified by asynchronous discharge to the spindles.
From the practical standpoint, then we may say that the amount and rate of response of a
stretch reflex are proportional to the amount and rate of stretching. In other words, the use of
bouncing or jerky movements in stretching will cause the muscle to contract with a vigor
proportional to that of the bouncing and jerking. It is rather obvious that this is not desirable
either in warming-up cold muscles for athletic participation or in work that is designed to
improve flexibility.
It would seem intelligent, then, for the physical educator and coach to apply known
principles. If it be desired to loosen up, lengthen, and relax muscle tissue, the use of a sustained
pull on the muscle would tend to eliminate the phasic component of the stretch reflex, and the
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pull should be of sufficient force to reach the threshold of the tendon organs; this will then
initiate the inverse myotatic reflex, which will inhibit the muscle under stretch and thus further
aid in stretching the muscle.
A stimulus which increases slowly in intensity produces a lower frequency of impulses than
a stimulus which rises very rapidly to the same level. Thus, a pull on a muscle with a given
force attained within 1 second produces an afferent impulse frequency of more than 100/sec., but
a slower increase in stretch, until the same force is applied, will within 6 seconds give a peak
volley of about 40 impulses/sec.
To summarize, the attainment of flexibility would seem to be best accomplished by a static
pull with reasonably large force applied.
B. Phasic stretch ÷ stimulates muscle spindles ÷ myotatic reflex ÷ causes muscle contraction in
the muscle you are trying to lengthen
C. Static stretch ÷ stimulates Golgi tendon organs ÷ inverse myotatic reflex ÷ causes motor unit
relaxation and total muscle relaxation in the muscle you are trying to lengthen
D. The attainment of flexibility is best accomplished with static stretching with enough force
applied to reach the threshold of the Golgi tendon organs
X.
Static Stretching
A. It takes time to make progress in flexibility. Must have a daily stretching program
B. Select simple exercises to begin stretching muscle groups
C. Be sure to warm-up the muscles gradually before stretching
D. Move into the stretching position slowly, continuing until stretch on muscle is felt. Excessive
pain is not part of a good stretching program
E. After reaching a good stretch position, hold that position for 10–15 seconds
F. Over a period of weeks, the time can be increased to 45–60 seconds
G Muscles being stretched should be as relaxed as possible
H. When stretching exercise is completed, release the body slowly from the position
I. Stretching exercises are not meant to be competitive. Trying too hard can lead to injury and a
loss of flexibility
XI.
PNF—Proprioceptive-Neuromuscular-Facilitation—Read in Appendix: PNF Stretching, p. 246
Stabilize
Muscle
GTO
Stabilize
GTO
GTO
Stabilize
Muscle
Contracts
GTO
XII. Dynamic Stretching—a type of functionally based stretching exercise that uses sport-specific
movements to prepare the body for activity. Read in Appendix: Dynamic Stretching, p. 247
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APPENDIX
1. PNF Stretching
2. Dynamic Stretching
3. Should Athletes Stretch Before
Exercise? (including GSSI Supplement
Should You Stretch Before Exercise?
and Georgia Tech Sports Medicine &
Performance Newsletter The Diminished
Role of Static Stretching)
4. Memory Jogger—Developing a
Stretching Program
5. Self-Test for Muscle Imbalance
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PNF Stretching
Proprioceptive Neuromuscular Facilitation
What is PNF Stretching?
Proprioceptive Neuromuscular Facilitation (PNF) is a more advanced form of flexibility training that involves
both the stretching and contraction of the muscle group being targeted.
PNF stretching was originally developed as a form of rehabilitation, and to that effect it is very effective. It
is also excellent for targeting specific muscle groups, and as well as increasing flexibility, (and range of
movement) it also improves muscular strength.
Warning!
Certain precautions need to be taken when performing PNF stretches as they can put added stress on the targeted
muscle group, which can increase the risk of soft tissue injury. To help reduce this risk, it is important to include
a conditioning phase before a maximum, or intense effort is used.
Also, before undertaking any form of stretching it is vitally important that a thorough warm up be
completed. Warming up prior to stretching does a number of beneficial things, but primarily its purpose is to
prepare the body and mind for more strenuous activity. One of the ways it achieves this is by helping to increase
the body's core temperature while also increasing the body's muscle temperature. This is essential to ensure the
maximum benefit is gained from your stretching.
How to Perform a PNF stretch
The process of performing a PNF stretch involves the following. The muscle group to be stretched is positioned
so that the muscles are stretched and under tension. The individual then contracts the stretched muscle group for
5–6 seconds while a partner, or immovable object, applies sufficient resistance to inhibit movement. Please
note; the effort of contraction should be relevant to the level of conditioning.
The contracted muscle group is then relaxed and a controlled stretch is applied for about 30 seconds. The
muscle group is then allowed 30 seconds to recover and the process is repeated 2–4 times. Refer to the diagrams
for a visual example.
The athlete and partner assume the
position for the stretch, and then
the partner extends the body limb
until the muscle is stretched and
tension is felt.
Partner and subject leg and hand
positions for PNF hamstring stretch.
Passive prestretch of hamstrings
during hold-relax PNF hamstring
Isometric action during hold-relax PNF hamstring stretch.
The athlete then contracts the
stretched muscle for 5–6 seconds
and the partner must inhibit all
movement. (The force of the
contraction should be relevant to
the condition of the muscle. For
example, if the muscle has been
injured, do not apply maximum
contraction.)
The muscle group is relaxed, then
immediately and cautiously pushed
past its normal range of movement
for about 30 seconds. Allow 30
seconds recovery before repeating
the procedure 2–4 times.
Increased ROM during passive stretch of hold-relax PNF hamstring stretch.
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DYNAMIC STRETCHING
A dynamic stretch is a type of functionally based stretching exercise that uses sport-specific
movements to prepare the body for activity. Dynamic stretching—also called mobility drills—places
an emphasis on the movement requirements of the sport or activity rather than on individual muscles.
This type of exercise can closely duplicate the movement requirements of a sport or activity. For
example, a walking knee lift stretch mimics the knee lift of a sprinter. Essentially, one can think of
dynamic stretching as actively moving a joint through the ROM required for a sport.
Dynamic and Ballistic stretches may appear similar; however, a number of key differences
significantly alter the effects of these activities such that dynamic stretching avoids the negative
effects associated with ballistic stretching. Dynamic stretching avoids bouncing and is performed in a
more controlled manner than ballistic stretching. The result is a controlled ROM that is often smaller
than that produced by ballistic stretching.
The ability to actively move a joint through a ROM is generally far more sport specific that the
ability to statically hold a stretch. Advantages of dynamic stretching include its ability to promote
dynamic flexibility and to replicate the movement patterns and ROM required for sport activities. As
a consequence, dynamic stretches are increasingly the preferred method of stretching during warmup, and ideally match the requirements of the specific warm-up.
The use of dynamic stretches during the specific part of the warm-up provides a number of key
advantages. Dynamic stretching helps promote the temperature-related benefits of the general warmup, unlike static stretching, which can lead to reduction in temperature. Additionally, a number of
joints can be integrated into a single stretch, often including multiplanar movements similar to those
that occur in sport. Thus dynamic stretches are extremely time efficient, which can be important
where training time is limited.
In dynamic stretching, unlike static stretching, the muscle does not relax during the stretch but
instead is active through the ROM; this is also more specific to the movements that occur in sport.
Even though it is an ideal warm-up activity, dynamic stretching may be less effective than static or
PNF stretching at increasing static ROM in situations in which an increased static ROM is needed,
static or PNF methods may be preferred.
When one is designing a dynamic stretching program, the starting point should be a careful
analysis of the major movement patterns within the given sport and ROM required for those
movements. One can then select exercises that replicate those movements via a series of dynamic
stretches. In this way it is possible to achieve a highly specific stretching program.
Dynamic stretching provides the opportunity to combine movements. This gives the strength and
conditioning professional a large number of combinations that can be used to provide variety
combinations that can be used to provide variety in the warm-up. Athletes can perform dynamic
stretching exercises either for a series of repetitions in the same place (e.g., 10 lunges) or for a series
of repetitions to cover a given distance (e.g., lunge for 15 m). Regardless of the method chosen, each
drill should start slowly and gradually increase the ROM, the speed, or both during subsequent
repetitions or sets. For example, athletes can perform the knee lift exercise over a distance of 15 ,
starting at a walk, and build to a skip over subsequent repetitions. This progression provides for an
increase in both speed and ROM. An effective warm-up utilizing dynamic stretching can be achieved
in 10 to 15 minutes.
In a dynamic stretch that mirrors a sport skill—such as a sprinter’s knee lift drill—it is important
that the stretch also emphasize the key skill factors required for the movements so that the most
important mechanics of the drill are reinforced. For example, if the knee lift drill is used in the warmup, effective body mechanics should be emphasized along with key joint positions such as
dorsiflexion of the ankle of the lifted foot. The use of dynamic stretches must always be coordinated
with appropriate sport techniques and never compromise proper technique.
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Do not:
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Do not ignore your body. Do not stretch to the point of pain
Do not stretch a muscle beyond its natural range.
Do not bounce when performing muscle stretching.
Do not hold your breath. Continue to breathe deliberately while stretching.
Do not extend to the point of muscle stretch reflex.
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Do warm up your muscles for at least five minutes prior to stretching.
Do pay attention to your body, feel you muscle’s natural limit.
Do start stretching slowly and work into your full extension.
Do be patient. Take your time and do it right.
Do breathe deeply to your full lung capacity
Do concentrate on staying relaxed.
Do stretch even when you are sore
Do:
The Exercises
Joint Rotations
From a standing position with your arms hanging loosely at your sides, flex, extend and rotate each of
the following joints:
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Fingers
Wrist
Elbows
Shoulders
Neck
Trunk and shoulder blades
Hips
Knees
Ankles
Feet and toes
Neck Mobility



Flexion/Extension—tuck your chin into your chest, and then lift your chin
upward as far as possible. 6 to 10 repetitions.
Lateral Flexion—lower your left ear toward your left should and then your right
ear to your right shoulder. 6 to 10 repetitions.
Rotation—Turn your chin laterally toward your left shoulder and then rotate it
toward your right shoulder. 6 to 10 repetitions
Shoulder Circles

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
Stand tall, feet slightly wider than shoulder-width apart, knees slightly bent
Raise your right should towards your right ear, take it backward, down and then
up again to the ear in a smooth action
Repeat with the other shoulder
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Arm Swings
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Stand tall, feet slightly wider than shoulder-width apart, knees slightly bent.
Keep the back straight at all times
Overhead/Down and Back—Swing both arms continuously to an overhead
position and then forward, down and backwards. 6 to 10 repetitions
Slide/Front Crossover—Swing both arms out to your sides and then cross them
in front of your chest. 6 to 10 repetitions.
Side Bends



Stand tall with good posture, feet slightly wider than shoulder-width apart, knees
slightly bent, hands resting on hips.
Lift your trunk up and away from your hips and bend smoothly first to one side,
then the other, avoiding the tendency to learn either forwards or backwards.
Repeat the whole sequence sixteen times with a slow rhythm, breathing out as
you bend to the side, and in as you return to the [center].
Hip Circles and Twists


Circles—With your hands on your hips and feet spread wider than your
shoulders, make circles with your hips in a clockwise direction for 10 to 12
repetitions. Then repeat in a counter clockwise direction.
Twists—Extend your arms out to your sides, and twist your torso and hips to the
left shifting your weight on to the left foot. Then twist your torso to the right
while shirting your weight to the right foot. 10 to 12 reps on each side.
Half Squat
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Stand tall with good posture holding your hands out in front of you for balance
Now bend at the knees until your thighs are parallel with the floor
Keep your back long throughout the movement, and look straight ahead.
Make sure that your knees always point in the same directions as your toes
Once at your lowest point, fully straighten your legs to return to your starting
position
Repeat the exercise sixteen times with a smoother, controlled rhythm
Breath in as your descend, and out as you rise
Leg Swings
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Flexion/Extension—stand sideways onto the wall
Weight on your left leg and your right hand on the wall for balance
10 to 12 repetitions on each leg
Cross-Body Flexion/Abduction—leaning slightly forward with both hands on a
wall and your weight on your left leg, swing your right leg to the left in front of
your body, pointing your toes upwards as your foot reaches its furthest point of
motion
Then swing the right leg back to the right as far as comfortable, again pointing
your toes up as your foot reaches its final point of movement.
10 to 12 repetitions on each leg.
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Lunges
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Standing tall both feet together ( starting position)
Keeping the back straight lunge forward with the right leg approx. 1 to 1.5 meter
The right thigh should be parallel with the ground and the right lower
Spring back to the starting position
Repeat with the left leg
12 to 16 repetitions on each leg
Ankle Bounce
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Double Leg Bounce—Leaning forward with your hands on the wall and your
weight on your toes, raise and lower both heels rapidly (bounce).
Each time, lift your heels one to two inches from the ground while maintaining
ground contact with the ball of your feet.
12 to 16 repetitions
Single Leg Bounce—Leaning forward with your hands on a wall and all your
weight on your left foot, raise the right knee forward while pushing to the left heel
towards the ground.
Then lower the right foot to the floor while raising the left heel one or two inches
Repeat in a rapid, bouncy fashion
12 to 16 repetitions on each leg.
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Vol. 11 No. 3 November–December 2002
Sports Medicine
& Performance
N E W S L E T T E R
PERFORMANCE
The Diminished Role of
Static Stretching
ow many times have you seen publications, this one
included, recommend that you perform a stretch to its
farthest point and hold for 30 seconds or for three
ten-second periods?
This type of movement is called static stretching. It is safe,
easy to learn, easy to execute, and has been proven as a means
of increasing flexibility. It is also a type stretching that should
play a limited, or at least different, role in your exercise
program.
“Recent research,” says Todd Elleribecker, MS., PT.,
C.S.C.S, “has identified temporary decreases in skeletal muscle
performance after static stretching. This includes decreases in
muscular strength and power. Applying this research to elite
athletes has led sports scientists and medical professionals to
now recommend static stretching before vigorous training or
competition at least 30–60 minutes before that activity starts
(instead of immediately before).” Ellenbecker’s comments
appeared in High Performance Coaching. Others go so far as to
say that static stretching at any time before a training session or
contest is counterproductive to performance.
But even if static stretching is what you are supposed to do
30–60 minutes before practice or an event, what should you do
immediately before it starts? Michael Alter, MS., author of the
immensely popular book, Sport Stretch, and Ellenbecker
recommend dynamic stretching. Says Alter, “Dynamic
stretching develops optimum flexibility, which is essential for
all sports. Flexibility training must be velocity-specific to
condition uid train the velocity-specific stretch receptors.”
Ellenbecker suggests that, in addition to dynamic
stretching, the athlete or exerciser jog in place or ride a
stationary bicycle immediately before the activity. But neither
seems to be consistent with the sport-specific recommendations.
H
Dynamic vs Ballistic Stretching
There is a difference between dynamic stretching and ballistic
stretching. The latter involves bobbing, bouncing, rebounding,
and rhythmic types of movement, according to Alter. It is very
controversial because it can cause injury and soreness. It also
fails to provide adequate time for the tissues to adapt to the
stretch and it increases muscle tension, making it hard to stretch
connective tissues. Although there are ways to gradually work
up to safe ballistic stretches, they are generally not a good idea.
Dynamic stretching, on the other hand, does not end with
bouncing or jerky movements. Instead, the idea is to execute a
controlled, moving stretch.
Given the disadvantages already described, should static
stretching be a part of your exercise routine? Yes, says
Ellenbecker. “Static stretching is most commonly recommended
after the activity when the body is very warm and maximal
elongation via stretching can occur. Static stretching after a
workout is also thought to speed recovery, decrease soreness,
and extend muscle length. The timing of static stretching has
changed but the relative importance of effectiveness has not.
Static stretching is also still recommended to prevent flexibility
deficits in problem areas.”
He told the Newsletter that, even though the recent research
involved elite athletes, static stretching 30–60 minutes among
recreational athletes an hour or so before going out to play
might be beneficial in preventing injuries. There is no hard
evidence to support this claim.
Tom Jurz, another stretching advocate, advises athletes to
use dynamic stretches before an activity and static stretches
when the major part of the workout has been completed and the
person is in a cool-down mode.
Sequence of Activities
Ellenbecker recommends the following sequence of activities
prior to, during, and after a game, event, or training session for
tournament level tennis players and other high- performance
athletes:
•
•
•
•
Active warm-up for 3–5 minutes immediately before the
activity
Dynamic, sport-specific stretches, including traditional
warm-up activities
Game, event, or training
Static stretches
The Newsletter, after consulting with Ellenbecker, offers a
variation of this sequence for serious exercisers and recreational
athletes.
•
•
•
•
•
Static stretches (30–60 minutes before an activity)
Active warm-up for 3–5 minutes immediately before
the activity
Dynamic, sport-specific stretches, including traditional
warm-up activities
Game, event, or training
Static stretches
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INJURY PREVENTION
Self-Test for Muscle Imbalance
Athletes are more susceptible to injuries when one muscle group is tighter than its opposing group. Newsletter
Editorial Board member Lyle J. Micheli, author of Healthy Runner's Handbook, tells us that there are three
muscle groups that are most likely to cause problems. They are the hip flexors, the hamstrings, and the calves
(along with the Achilles tendons).
Micheli suggests three self-tests to determine muscle group tightness. For the hip
flexors, lie on your back and draw both knees to your chest. Continue holding the
right knee to the chest while extending the left leg until it lies flat on the floor.
Repeat the procedure to the other side. If you can't lay the extended leg flat, your hip
flexors are too tight and in need of stretching exercises.
(Recommended exercise: Tubed Leg Swing)
To test hamstring flexibility, start lying with knees bent and
soles of your feet touching a wall. Raise both legs, keep
your knees straight, and move your buttocks as close to the
wall as possible. If you cannot move your buttocks closer
than eight inches from the wall, your hamstrings are excessively tight. (Recommended
exercise: Hamstring Stretch)
For the calves/Achilles tendons, sit on the floor with your left leg tucked inward and
right leg extended. Reach forward, try to grasp the toes of your right foot, and pull
them toward you. The bottom of your foot should form a right angle with the floor. If not, you have a tight calf
and Achilles tendon. (Recommended exercise: Wall Stretch)
GEORGIA TECH
SPORTS MEDICINE & PERFORMANCE NEWSLETTER
December 2001