Transcript Slide 1

Outline:
1.Benefits of Good
Flexibility
2.Factors Affecting
Flexibility
3.Assessment of
Flexibility
4.Evaluating Body
Posture
5.Principles of Muscular
Flexibility Prescription
6.When to Stretch?
7.Flexibility Exercises
8.Preventing &
Rehabilitating Low-Back
Pain
Chapter 8
Muscular Flexibility
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Muscular Flexibility
• When joints are not regularly moved
through their full range of motion, muscles
and ligaments shorten over time, and
flexibility decreases
• Repetitive movement through regular/
structured exercise as in running, cycling,
or aerobics without proper stretching
causes muscles and ligaments to tighten
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Muscular Flexibility
• Flexibility is the achievable range of
motion at a joint or group of joints without
causing injury
• Some muscular/skeletal problems and
injuries, related to a lack of flexibility,
occur when a tight muscle is abruptly
forced beyond its achievable range of
motion
• A decline in flexibility can lead to poor
posture and aches and pains that lead to
limited, painful joint movement
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Muscular Flexibility
• 80% of all low-back problems in the U.S.
result from improper alignment of the
vertebral column and pelvic girdle as a
direct result of inflexible and weak
muscles
• This backache syndrome costs U.S.
industry billions yearly in lost productivity,
health services, and worker compensation
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Benefits of Good Flexibility
• Promotes healthy muscles and joints
• Improves elasticity of muscles and
connective tissue around joints, enhancing
freedom of movement
• Makes activities of daily living (turning,
lifting, and bending) easier to perform
• Regular stretching increases circulation to
the muscles
• Helps prevent low-back and other spinal
column problems
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Benefits of Good Flexibility
• Improves and maintains good postural
alignment
• Promotes proper and graceful body
movement
• Improves personal appearance and selfimage
• Helps develop and maintain motor skills
throughout life
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Flexibility in Older Adults
• Older adults lose mobility and may be
unable to perform simple tasks such as
bending forward or turning
• Individuals who lose range of motion with
age are unable to look over their shoulder
to switch lanes or parallel park, increasing
the risk for automobile accidents
• Lack of good range of motion can severely
hamper physical activity and exercise
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Flexibility in Older Adults
• Lack of flexibility may cause falls and
other injury
• A simple stretching program can alleviate
or prevent this problem and help people
return to an exercise program
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Factors Affecting Flexibility
• Genetic factors
• Physical activity
• Joint structure (shape
of the bones)
• Joint cartilage
• Ligaments
• Tendons
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Muscles
Skin
Tissue injury
Adipose tissue (fat)
• All influence range
of motion about a
joint
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Factors Affecting Flexibility
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Body temperature
Age
Gender
All affect flexibility
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Factors Affecting Flexibility
• Changes in muscle temperature can increase or
decrease flexibility by as much as 20%
– Warm muscles are more flexible
– Cool temperatures impede range of motion
• Flexibility is affected by the amount of adipose
tissue (fat) in and around joints and muscle
tissue
• Excess adipose tissue increases resistance to
movement, and the added bulk hampers joint
mobility because of the contact between body
surfaces
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Factors Affecting Flexibility
• Women are more flexible than men and retain
this advantage throughout life
• Aging decreases extensibility of soft tissue,
resulting in less flexibility in both sexes
• Sedentary living is the most significant
contributor to lower flexibility because muscles
lose elasticity and tendons and ligaments tighten
and shorten
• Adipose tissue increases with inactivity, which
decreases a joint’s range of motion
• Injury to muscle tissue and tight skin from
excessive scar tissue negatively effect range of
motion
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Evaluating Body Posture
• Good posture enhances
Personal appearance
Self-image
Confidence
Improves balance and endurance
Protects against misalignment-related aches
and pains
– Prevents falls
– Enhances overall sense of well-being
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Evaluating Body Posture
• Poor posture is a risk factor for
musculoskeletal problems of the neck,
shoulders, lower back, and strains the hips
and knees
• Bad posture, weak and inelastic muscles
are a leading cause of chronic low-back
problems
• Proper body mechanics means using
correct positions in all activities of daily
life, including sleeping, sitting, standing,
walking, driving, working, exercising
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Principles of Muscular Flexibility
Prescription
• Although genetics play a crucial role in
flexibility, range of joint mobility can be
increased and maintained through a
regular stretching program
• Since range of motion is highly specific to
each body part, a comprehensive
stretching program should include all body
parts and follow basic guidelines for
flexibility development
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Principles of Muscular Flexibility
Prescription
• Overload and specificity of training
principles apply to the development of
flexibility
• To increase total range of motion of a
joint, the specific muscles around the joint
must be stretched progressively beyond
their normal length
• Principles of mode, intensity, repetitions,
and frequency of exercise apply
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Modes of Training
• Three modes of stretching exercises can
increase flexibility
– Ballistic stretching
– Slow-sustained stretching
– Proprioceptive neuromuscular facilitation (PNF)
stretching
• Research shows all three types improve
flexibility
• Each technique has certain advantages
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Ballistic Stretching
• Ballistic (or dynamic) stretching: Exercises
done with jerky, rapid, bouncy movements
• May cause muscle soreness and injury from small
tears to the soft tissue
• Precautions must be taken not to overstretch
ligaments because they undergo plastic or
permanent elongation which leads to excessively
loose joints, increasing the risk for injuries
• Slow, gentle, controlled ballistic stretching is
effective in developing flexibility
• Most people can perform it safely
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Slow-Sustained Stretching
• Slow-sustained stretching: Exercises in
which the muscles are lengthened
gradually through a joint’s complete range
of motion and the final position is held for
a few seconds
• Relaxes muscles, achieving greater length
• Low risk for injury
• Most frequently used and recommended
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Proprioceptive Neuromuscular
Facilitation (PNF)
• Proprioceptive neuromuscular
facilitation (PNF): Stretching technique
that uses reflexes and neuromuscular
principles to relax the muscles being
stretched
• Based on a “contract-and-relax” method
• Partner assisted
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Proprioceptive Neuromuscular
Facilitation (PNF)
• Procedure is as follows:
– Assistant provides initial force by slowly pushing in the
direction of the desired stretch
– Person being stretched then applies force in the opposite
direction of the stretch, against the assistant who tries
to hold the initial degree of stretch, resulting in an
isometric contraction at the angle of the stretch
– The contraction is held 4-5 seconds, then the person
being stretched relaxes the muscles and the assistant
slowly increases the stretch
– The procedure is repeated
– Steps 1-4 are repeated 2-5 times with the final stretch
position held for 15-30 seconds
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Proprioceptive neuromuscular facilitation (PNF) stretching
technique: (a) isometric phase (b) stretching phase
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Proprioceptive Neuromuscular
Facilitation (PNF)
• Theoretically, the isometric contraction helps
relax the muscle being stretched, which results in
lengthening the muscle
• Increases strength of the muscle being stretched
from the isometric contraction
• Data shows about 17% and 35% increase in
absolute strength and muscular endurance in the
hamstring group after 12 weeks of PNF
• Results were consistent in men and women
• Disadvantages of PNF are more pain, the need for
a partner, time consuming
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Intensity
• Degree of stretch to the point of mild
discomfort or tightness at the end of the
range of motion
• All stretching should be done slightly
below the pain threshold
• Participants should try to relax the muscle
being stretched
• If you feel pain, the load is too high and
may cause injury
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Repetitions
• Time required for a flexibility session is based on
the number of repetitions and the length of time
each repetition is held in the final stretched
position
• General recommendation
– Each exercise should be done 2-4 times
– Each time hold the final position 15-30 seconds
– Gradually increase the time each repetition is held to a
maximum of 1 minute
• Individuals susceptible to flexibility injuries
should limit each stretch to 20 seconds
• Pilates exercises are recommended for these
individuals to increase joint stability
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Frequency of Exercise
• Flexibility exercises should be performed a
minimum of 2-3 days per week, ideally 57 days per week
• After 6-8 weeks, flexibility can be
maintained with only 2-3 sessions per
week of 3 repetitions of 15-30 seconds
each
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When to Stretch
• Warming up means starting a workout
slowly followed by gentle stretching (not
through entire range of motion)
• A warm-up that progressively increases
muscle temperature and mimics
movement that will occur during training
enhances performance
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When to Stretch
• Gentle stretching with warm-up
recommended for some activities
– 3- to 5-minute warm-up for steady activities
– Up to 10 minutes for stop-and-go activities
and athletic participation in general
• Extensive stretching prior to performing
events that rely on strength and power for
peak performance is not recommended
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When to Stretch
• Evidence is unclear regarding whether
stretching before or after exercise is best
for injury prevention
• Good time to stretch is after aerobic
exercise due to higher body temperature
• Stretching helps fatigued muscles
reestablish their normal resting length and
prevent unnecessary pain
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Preventing & Rehabilitating LowBack Pain
• Over 95% of all back pain is related to
muscle/tendon injury
• 1%-5% is related to intervertebral disc
damage
• Most common cause of low-back pain is
physical inactivity, particularly sitting,
which causes back muscles to shorten,
stiffen, and weaken
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Incorrect & correct pelvic
alignment
• Weakening of the
abdominal and gluteal
muscles, along with
tightening of the lower
back muscles, causes
an unnatural forward
tile of the pelvis
resulting in lower back
pain
• Pelvis tilt is
aggravated by fat
around the midsection
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Effects of Stress
• Excessive stress causes muscles to contract
• Frequent tightening of the muscles can throw the
back out of alignment and constrict blood vessels
that supply oxygen and nutrients to the back
• Chronic stress releases hormones linked to
muscle and tendon injuries
• People under stress forget about proper body
mechanics, increasing risk for injury
• Proper stress management should be in your
back care program
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Personal Flexibility & Low-Back
Conditioning Program
• Recommendations call for isometric
contractions of 2-20 seconds during each
repetition for some exercises for back
health
• Length of the hold will depend on your
current fitness level and difficulty of each
exercise
• Most exercises begin with a 2-10 second
hold
• After several weeks increase the hold to
30 seconds
© 2010 Cengage-Wadsworth