Transcript File - IMSA Sports Medicine

Dynamic
Stretching
1
Objectives
• Discuss the different advantages/disadvantages of ballistic,
static and dynamic stretching
• Determine what type of stretching is most appropriate for
different sports
• Demonstrate proper mechanics with dynamic stretches
• Design a sport-specific warm-up for each sport
• Discuss importance of cool-down stretching
• Have fun!
2
Effects of Stretching
Acute Effects
• Elongating the elastic component of the musculotendinous
unit
• Improving blood flow
Chronic Effects
• Adding sarcomeres
• Lengthen shortened tissues
• Decrease muscle/joint stiffness
3
Types of Stretching Activities
•
•
•
•
Static Stretching
Ballistic Stretching
Dynamic Stretching
Proprioceptive Neuromuscular Facilitation
Stretching
4
Static Stretching
• The muscles and connective tissue being stretched are held in a
stationary position at their greatest possible length for some
period.
• Held a minimum of 15-30 seconds 1 2 3
• Maintain good limb alignment
• Advantages
• Less overall force (decreases danger of exceeding tissue
extensibility limits)
• Lower energy requirements
• Lower likelihood of muscle soreness 4
• Less effect on Ia and II spindle afferent fibers
• Disadvantages
• May weaken muscles for up to 30 minutes following
• Easy to compensate
5
Ballistic Stretching
• Uses quick movements that impose a change in length of muscle
or connective tissue
• Appear to be jerky in nature
• Advantages
• Assist in preparing for plyometric activities
• Can increase long-term flexibility in athletes
• Disadvantages
• Greater chance of muscle soreness and injury
• Excessive uncontrolled forces
• Proposed neurologic inhibitory influences associated with
rapid-type stretching 5-7, 8, 9, 10, 11
6
PNF Stretching
• Capitalize on the use of the neurophysiologic concept of
stretch activation
• Contract-relax (CR) sequence, agonist contraction (AC) or
contract-relax-agonist contraction (CRAC)
• Works by activating the Golgi Tendon Organ, inhibiting the
muscle being stretched, and using the principle of reciprocal
inhibition 15
• Advantage: Can work well on stubborn muscles
• Disadvantage: Requires therapist with constant
communication
7
Dynamic Stretching
• Somewhat similar to ballistic stretching
• Instead of bouncing, has repeated motions
through full-range
• Recent evidence in the literature suggests this
is the best warm-up for athletes 12, 13, 14
8
ACUTE MUSCLE STRETCHING INHIBITS MAXIMAL
STRENGTH PERFORMANCE
Kokkonen, Nelson, Cornwell – Res. Q. Exercise Sport, 1998, 69, 411-415
• 15 male, 15 female
college PE majors
• One-repetition maximum
(1RM) lift of prone knee
flexion and seated knee
extension tested
• Two treatments: 10
minutes of quiet sitting
(NS) or 20 minutes of
passive static stretching of
hip, thigh, and calf groups
(ST)
• ST group demonstrated
16% improvement in
flexibility in sit-and-reach
test
• 8.1% decrease in 1RM of
knee flexors and extensors
• Recommend avoiding
intense static stretching
prior to any event in
which success is related to
maximal strength output
EFFECT OF ACTIVE RECOVERY ON ACUTE STRENGTH
DEFICITS INDUCED BY PASSIVE STRETCHING
Viale, Nana-Ibrahim, and Martin - Journal of Strength and Conditioning Research, 2007, 21(4), 1233–
1237
• 8 subjects used as own controls
• Both legs subjected to same
warm-up and stretching
treatments, then one leg
exposed to active recovery
(experimental treatment) and
other leg recovered passively
(control)
• Knee extensor single leg
maximal voluntary contraction
(MVC) measured at baseline,
post-stretching, and postrecovery
• MVC baseline strength of
control and treated legs
decreased post-stretching by
8.0% and 8.9%.
• MVC baseline strength further
decreased post-recovery by
1.3% and 1.2%
• Results confirm significant
strength is lost post-stretching.
• Results fail to show greater
improvement in strength in
active vs passive recovery
• Indicate that muscular exercises
during poststretching period are
unlikely to minimize stretchinduced strength deficits
ACUTE EFFECT OF STATIC AND PROPRIOCEPTIVE
NEUROMUSCULAR FACILITATION STRETCHING ON MUSCLE
STRENGTH AND POWER OUTPUT
Marek, et al – Journal of Athletic Training 2005; 40(2): 94-103
• Static and PNF stretching reduced peak torque,
mean power output, and EMG amplitute of vastus
lateralis and rectus femoris muscles at both slow
and fast velocities
• AROM and PROM increased as a result of static
and PNF stretching
• Practitioners need to consider the risk-to-benefit
ratio when incorporating static or PNF stretching
EFFECTS OF DIFFERENTIAL STRETCHING PROTOCOLS
DURING WARM-UPS ON HIGH-SPEED MOTOR
CAPACITIES IN PROFESSIONAL SOCCER PLAYERS
Little and Williams - Journal of Strength and Conditioning Research, 2006, 20(1), 203–207
• 18 professional soccer players
from English Premier League
• 3 different warm-up protocols
tested
– Static Stretching
– No Stretching
– Dynamic Stretching
• 4 outcomes measured
–
–
–
–
Vertical Jump
10-meter Acceleration
20-meter Maximal Speed
Zig-Zag Agility
•
•
•
•
No difference between static and
no stretch in vertical jump, 10meter acceleration, or zig-zag
agility
Static stretching better than no
stretching in 20-meter maximal
speed
Dynamic stretching superior to
both no stretching and static
stretching in 3 of 4 outcomes
Concluded that dynamic stretching
is probably most effective as
preparation for the high-speed
performances required in sports
such as soccer
ACUTE MUSCLE STRETCHING INHIBITS MUSCLE STRENGTH
ENDURANCE PERFORMANCE
Nelson, Kokkonen, Arnall - Journal of Strength and Conditioning Research, 2005, 19(2), 338-43
• Experiment 1: kneeflexion strength endurance
exercise measured at 60%
and 40% body weight
following either nostretching or stretching
regimen
• Stretching significantly
reduced muscle strength
endurance by 24% at 60%
body weight and by 9% at
40% body weight
• Experiment 2: knee
flexion muscle strength
endurance test performed
at 50% body weight on 4
different days, with 2 tests
following a no-stretch
regimen and 2 tests
following a stretching
regimen
• Stretching significantly
reduced muscle strength
endurance by 28%
Recommend avoiding stretching prior to any activity where endurance is needed.
THE EFFECT OF STATIC STRETCHING ON PHASES OF
SPRINT PERFORMANCE IN ELITE SOCCER PLAYERS
Sayers, Farley, Fuller, Jubenville, Caputo - J Strength Cond Res, 2008, 22(5), 1416-21
• 20 elite female soccer players
• Randomly assigned to stretch or no-stretch
• Looked at acceleration, maximal-velocity sprint
time, and overall sprint time between stretch and
no-stretch conditions
• Static stretching produces negative effect on sprint
performance and should not be included as part of
preparation routine for physical activity that
requires sprinting
Retention
• 2-4 weeks after a 6 week stretching program 16
• 3-5x / week can produce GAINS
• 1x / week may be sufficient to MAINTAIN
• May need to be part of daily routine for someone
with significant deficits
• Should be able to address your needs/modify as
needed (previous surgery, long-term disease,
upcoming race, etc)
15
How long???

One 30-second stretch is enough to decrease
strength by 5.4%
 Six 30-second stretches are enough to decrease
strength by 12.4%
A single 30-s stretch is sufficient to inhibit maximal voluntary
strength. Winchester, Nelson, Kokkonen. Res Q Exerc Sport.
2009 Jun; 80(2): 257-61
16
Summary
• Static stretching may make better cool-down in
sports that involve maximum strength, endurance,
sprinting, etc.
• Dynamic stretching may make better warm-up
• Be Functional
• Flexibility is still important part of overall
athleticism and treatment
• Have fun!
17
References
1. Bandy WD, Irion JM. The effect of time of static stretch on the flexibility of the hamstring muscles. Phys Ther 1994; 74:845-852.
2. Lentell G, Hetherington T, Eagan J, et al. The use of thermal agents to influence the effectiveness of a low-load prolonged stretch. J Orthop Sports
Phys Ther. 1992; 5: 200-207.
3. Madding SW, Wong JG, Hallum A, et al. Effects of duration of passive stretching on hip abduction range of motion. J Orthop Sports Phys Ther.
1987; 8:409-416.
4. deVries HA. Evaluation of static stretching procedures for improvement of flexibility. Res Q. 1962; 33:222-229.
5. Entyre BR, Abraham LD. Antagonist muscle activity during stretching: a paradox reassessed. Med Sci Sports Exerc. 1988; 20:285-99.
6. Entyre BR, Abraham LD. Ache-reflex changes during static stretching and two variations of PNF techniques. Electroencephalogr Clin
Neurophysiol. 1986; 63:174-179.
7. Entyre BR, Lee EJ. Chronic and acute flexibility of men and women using three different stretching techniques. Res Q. 1988; 222:228.
8. Moore M, Hutton R. Electromyelographic investigation of muscle stretching techniques. Med Sci Sports Exerc. 1980; 12:322-329.
9. Shindo M, Harayama H. Kondo K, et al. Changes in reciprocal Ia inhibition during voluntary contraction in man. Exp Brain Res. 1984; 53:400-408.
10. Zachazewski JE. Flexibility for sport. In: Sanders B, ed Sports Physical Therapy. Norwalk, CT: Appleton & Lange, 1990.
11. Zachazewski JE. Improving flexibility. In: Scully RM, Barnes MR, eds. Physical Therapy. Philadelphia: J.B. Lippincott; 1989.
12. Herman SL and Smith DT. Four-Week dynamic stretching warm-up intervention elicits longer-term performance benefits. J Strength and Cond Res.
2008; 22(4): 1286-1297.
13. Viale F, Nana-Ibrahim S, and Martin RJF. Effect of Active Recovery on Acute Strength Deficits Induced by Passive Stretching. J Strength and
Cond Res; 2007; 21(4):1233-1237.
14. Little T and Williams AG. Effects of differential stretching protocols during warm-ups on high-speed motor capacities in professional soccer
players. J Strength and Cond Res. 2006; 20(1): 203-207.
15. Hutton RS. Neuromuscular basis of stretching exercises. In: Komi PV, ed. Strength and Power in Sports. Boston: Blackwell Scientific; 1992:2938.
16. Zebas CJ, Rivera ML. Retention of flexibility in selected joints after cessation of a stretching exercise program. In : Dotson CO, Humphrey JH,
eds: Exercise Physiology: Current Selected Research Topics. New York: AMS Press; 1985.
18