Download Warm-Up and Stretching

chapter
14
Warm-Up
and Stretching
Chapter Objectives
• Identify the benefits and components of a preexercise
warm-up.
• Assess the suitability of performing stretching
exercises for a warm-up.
• Identify factors that affect flexibility.
• Describe flexibility exercises that take advantage of
proprioceptive neuromuscular facilitation.
• Explain the mechanisms that cause the muscular
inhibition that improves the stretch.
• Select and apply appropriate static and dynamic
stretching methods.
Warm-Up
• Warming up can have the following positive
impacts on performance:
– Faster muscle contraction and relaxation of both agonist
and antagonist muscles
– Improvements in the rate of force development and
reaction time
– Improvements in muscle strength and power
– Lowered viscous resistance in muscles
– Improved oxygen delivery due to the Bohr effect whereby
higher temperatures facilitate oxygen release from
hemoglobin and myoglobin
– Increased blood flow to active muscles
– Enhanced metabolic reactions
– An increased psychological preparedness for performance
Warm-Up
• Components of a Warm-Up
– A general warm-up period may consist of 5 to 10
minutes of lower intensity aerobic exercise, such as
jogging or skipping.
– A specific warm-up period incorporates movements
similar to the movements of the athlete’s sport. It
involves 8 to 12 minutes of dynamic stretching
focusing on movements that work through the range
of motion required for the sport.
Key Point
• The warm-up is an integral part of the
training session. Strength and conditioning
professionals should plan warm-ups
incorporating short-, medium-, and longterm considerations that will contribute to
the overall development of the athlete.
Warm-Up
• RAMP protocol:
– Raise: Elevate body temperature, heart rate,
respiration rate, blood flow, and joint fluid viscosity
via low-intensity activities that simulate the
movement patterns of the upcoming activity.
– Activate and Mobilize: Actively move through a
range of motion.
– Potentiate: Perform sport-specific activities that
progress in intensity until the athlete is performing at
the intensity required for the subsequent competition
or training session.
Dynamic Stretching During Warm-Up
• Research suggests dynamic stretching is the
preferred option for stretching during warm-up.
• Consider the range of motion and stretch-shortening
cycle requirements of the sport when designing a
warm-up.
Lunge With Twist
Walking Knee Lift
Walking Side Lunge
Flexibility
• Flexibility is a measure of range of motion
(ROM) and has static and dynamic components.
• Static flexibility is the range of possible
movement about a joint and its surrounding
muscles during a passive movement.
• Dynamic flexibility refers to the available
ROM during active movements and
therefore requires voluntary muscular
actions.
Flexibility
• Factors Affecting Flexibility
– Joint Structure
• Structure determines the joint’s range of motion.
– Age and Sex
• Older people tend to be less flexible than younger
people; females tend to be more flexible than males.
– Connective Tissue
• Elasticity and plasticity of connective tissues affect
ROM.
Flexibility (continued)
• Factors affecting flexibility
– Stretch tolerance
• The ability of an athlete to tolerate the discomfort
of stretching.
– Neural control
• Range of motion is controlled by the central and
peripheral nervous system, including both
afferent and efferent mechanisms.
(continued)
Flexibility
• Factors Affecting Flexibility
– Resistance Training
• Exercise through a full ROM and develop both agonist
and antagonist muscles to prevent loss of ROM.
– Muscle Bulk
• Large muscles may impede joint movement.
– Activity Level
• An active person tends to be more flexible than an
inactive one, but activity alone will not improve
flexibility.
Flexibility
• Frequency, Duration, and Intensity of
Stretching
– Acute effects of stretching on ROM are transient;
for longer-lasting effects a stretching program is
required.
– Minimum of twice a week for at least 5 weeks
– Individual stretches should be held to the point of
mild discomfort, but not pain, for at least 15-30 sec.
Flexibility
• When Should an Athlete Stretch?
– Following practice and competition
• Post-practice stretching facilitates ROM improvements
because of increased muscle temperature.
• Stretching should be performed within 5 to 10 minutes
after practice.
• Post-practice stretching may also decrease muscle
soreness although the evidence on this is ambiguous.
Flexibility
• When Should an Athlete Stretch?
– As a separate session
• If increased levels of flexibility are required, additional
stretching sessions may be needed.
• In this case, stretching should be preceded by a
thorough warm-up to allow for the increase in muscle
temperature necessary for effective stretching.
• This type of session can be especially useful as a
recovery session on the day after a competition.
• For longer-lasting effects, a daily stretching program
is required.
• Stretching should be preceded by a thorough warmup to allow for the increase in muscle temperature
Can stretching Reduce Injury Risks and
Enhance Athletic Performance?
•
–
There are data that show that stretching can both
enhance and hinder performance.
–
•
Probably depends on the sport/activity and the amount of
initial flexibility a person has.
Excessive flexibility decreases stability, while insufficient
flexibility decreases ROM and may hinder normal
movement patterns (both too much and too little can
cause problems).
For example, both excessive ER & inadequate IR in the
throwing arm of a pitcher increases the risk of internal
impingement. However, a pitcher with inadequate ER in
the throwing shoulder (normal is approx 120-130 deg) will
not be able to throw hard & performance may decrease.
Can stretching Reduce Injury Risks and
Enhance Athletic Performance?
•
–
–
•
Although stretching helps warm up the neuromuscular
system, a general warm-up (e.g., 5 min walk on a
treadmill) may be even more effective in warming up
muscle tissue.
Both muscle and nerves function better when warm
Warm muscles are less likely to be injured compared to cold
muscles
Stretching has not conclusively been shown to result
in either a decrease or increase in injuries rates
Proprioceptors and Stretching
• Stretch reflex and reciprocal
inhibition
– A stretch reflex occurs when
muscle spindles in the agonist
(quadriceps in the example
shown) are stimulated due to a
rapid stretch of the agonist,
causing the agonist to contract.
– Reciprocal inhibition occurs by
stimulation of an inhibitory
interneuron that inhibits the
antagonist (hamstrings in the
example shown), promoting
relaxation of the antagonist.
– By reciprocal inhibition, when an
agonist contracts, the antagonist
relaxes.
Proprioceptors and Stretching
• Autogenic inhibition
– Autogenic inhibition
occurs when high tension
in the agonist (quadriceps
in the example shown)
stimulates golgi tendon
organs in the tendon of
the agonist, causing
relaxation in the agonist
due to stimulation of an
inhibitory interneuron that
inhibits the agonist.
Types of Stretching
• Static Stretch
– A static stretch is slow and constant, with the end position
held for 30 seconds.
• Ballistic Stretch
– A ballistic stretch typically involves active muscular effort
and uses a bouncing-type movement in which the end
position is not held (which may evoke the stretch reflex).
• Dynamic Stretch
– A dynamic stretch is a type of functionally based
stretching exercise that uses sport-specific movements to
prepare the body for activity.
• Proprioceptive Neuromuscular Facilitation (PNF)
– A neuromuscular inhibition technique which stimulates
proprioceptors in a manner that results in muscle
lengthening and increased ROM (the muscle being
stretched is arbitrarily referred to as the antagonist).
Static Stretching
•
•
–
–
•
•
•
Muscle slowly elongated beyond point of tissue resistance,
but individual should be comfortable, relaxed, & pain-free.
15s, 30s, and 60s stretch durations have all demonstrated
significant increases in muscle elongation.
In younger individuals, no differences in muscle elongation
between 30s or 60s durations, but both more effective than 15s
duration.
In individuals > 65 y.o., 60s durations produced greater ROM
gains that persisted longer compared to 15s or 30s durations.
Repeat stretch at least 1-2 times for maximum improvement.
Progressively increase stretch as muscle tension decreases.
Safer than ballistic stretching, with less tissue trauma and
post-exercise soreness.
Precautions for Static Stretching
• Decrease stretch intensity if you experience pain,
radiating symptoms, or loss of sensation.
• Use caution when stretching a hypermobile joint.
• Avoid combination movements that involve the
spine (e.g., extension with lateral flexion; flexion
with rotation).
• Stabilizing muscles should be active to protect
other joints and prevent unwanted movements.
Static Stretching Exercises
Look Right and Left
Flexion and Extension
Straight Arms Behind Back
Seated Lean-Back
Behind-Neck Stretch (Chicken Wing)
Cross Arm in Front of Chest
Arms Straight Up Above Head (Pillar)
Spinal Twist (Pretzel)
Semi–Leg Straddle
Forward Lunge (Fencer)
Supine Knee Flex
Side Bend With Straight Arms
Side Bend With Bent Arm
Side Quadriceps Stretch
Sitting Toe Touch
Semistraddle (Figure Four)
Straddle (Spread Eagle)
Butterfly
Wall Stretch
Step Stretch
Guidelines for Dynamic Stretching
• Carry out 5 to 10 repetitions for each movement,
either in place or over a given distance.
• Progressively increase the ROM on each
repetition, but control the movement throughout.
• Increase the speed of motion on subsequent sets
where appropriate.
• Actively control muscular actions as you move
through the ROM.
• Maintain good form and technique throughout
Dynamic Stretching Exercises
Arm Swings
Inchworm
Lunge Walk
Lunge With Overhead Side Reach
Walking Knee Lift
Forward Lunge With Elbow to Instep
Heel-to-Toe Walk
Walking Over and Under
Walking Over and Under (continued)
Inverted Hamstring Stretch
(continued)
Inverted Hamstring Stretch (continued)
Straight-Leg March
Spiderman Crawl
PNF (Hold-Relax Technique)
Figures 13.3, 13.4, and 13.5
• a) Initial passive prestretch (10-15 s) of antagonist
(hamstrings in example shown)
• b) Isometric muscle action of antagonist (6 s) – autogenic
inhibition
• c) Longer passive stretch of antagonist (30 s) with increased
ROM.
• Repeat technique1-2 times.
a
b
c
PNF (Contract-Relax Technique)
Figures 13.6, 13.7, and 13.8
• a) Initial passive prestretch (10-15 s) of antagonist
(hamstrings in example shown)
• b) Concentric muscle action of antagonist through full ROM
(6 s) – autogenic inhibition
• c) Longer passive stretch of antagonist (30 s) with increased
ROM.
• Repeat 1-2 times.
PNF (Hold-Relax With Agonist
Contraction
Technique)
Figures
13.3, 13.4,
and 13.5
• a) Initial passive prestretch (10-15 s) of antagonist
(hamstrings in example shown)
• b) Isometric muscle action of antagonist (6 s) – autogenic
inhibition
• c) Both a longer passive stretch of antagonist (30 s) AND
concentric or isometric action of agonist (hip flexors in
example shown) used to increase the stretch with increased
ROM – autogenic inhibition and reciprocal inhibition.
• Repeat technique1-2 times.
a
b
cc
Key Points
• The hold-relax with agonist contraction is
the most effective PNF stretching technique
due to facilitation via both reciprocal
inhibition and autogenic inhibition.
• Muscle stretching is also occurring during
PNF stretching techniques, especially
during hold-relax with agonist contraction
(both agonist and antagonist are
strengthened).
Common Partner PNF Stretching
(Hamstrings PNF Shown Previously)
Figures 13.12 and 13.13
Calves
Chest
Shoulders
Quadriceps/
Hip Flexors
Groin