Download - Stretching Lecture

8/13/2019 Stretching Lecture

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STRETCHINGSTRETCHINGLoris BertolacciLoris Bertolacci


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STRETCHINGSTRETCHING

PNFPNFStretchingStretching

Passive stretchingPassive stretching

Active stretchingActive stretching

Static stretchingStatic stretching

Dynamic stretchingDynamic stretching

Ballistic stretchingBallistic stretching

Resistance StretchingResistance Stretching


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STRETCHREFLEXSTRETCHREFLEX

The Stretch ReflexThe Stretch Reflex

The more sudden the change in muscle length, theThe more sudden the change in muscle length, thestronger the muscle contractions will bestronger the muscle contractions will be

(plyometric, or "jump", training is based on this(plyometric, or "jump", training is based on thisfact). This basic function of the muscle spindlefact). This basic function of the muscle spindlehelps to maintain muscle tone and to protecthelps to maintain muscle tone and to protect

the body from injury.the body from injury.

One of the reasons for holding a stretch for aOne of the reasons for holding a stretch for aprolonged period of time is that as you hold theprolonged period of time is that as you hold the

muscle in a stretched position, the musclemuscle in a stretched position, the musclespindle habituates (becomes accustomed to thespindle habituates (becomes accustomed to the

new length) and reduces its signaling.new length) and reduces its signaling.Gradually, you can train your stretch receptorsGradually, you can train your stretch receptorsto allow greater lengthening of the muscles.to allow greater lengthening of the muscles.

BUT?BUT?


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SomeWordsSomeWords

Reciprocal InhibitionReciprocal Inhibition

Bodybuilders should stretchBodybuilders should stretch

Contortionists should strenghtenContortionists should strenghten

Specific Joint LaxitySpecific Joint Laxity

Muscular Imbalances: Janda?Muscular Imbalances: Janda?

PNF STRETCH?PNF STRETCH?Yoga SpinYoga SpinA sequence ofA sequence ofstretching and breathing used in conjunction withstretching and breathing used in conjunction withflowing chi (energy). A great preflowing chi (energy). A great pre--event treatmentevent treatment

to increase flexibility and balance the body andto increase flexibility and balance the body andmind connection.mind connection.


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30%.

??????

Is that

Ballisitic?


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MUSCLEMUSCLE

Muscle FiberMuscle Fiber

MyofibrilsMyofibrils--SarcomeresSarcomeres

MyofilamentsMyofilaments--Actin/Myosin. ( Sliding myofilament theory)Actin/Myosin. ( Sliding myofilament theory)

Function of muscle is to develop tensionFunction of muscle is to develop tension

Muscle BalanceMuscle Balance

Muscle ControlMuscle Control

AgeAge

ImmobilizationImmobilization


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CONNECTIVETISSUECONNECTIVETISSUE

AlterScience ofStretchingAlterScience ofStretching

Fibrous connective tissueFibrous connective tissue--CollagenCollagen Elastic connective tissueElastic connective tissue--Elastic fibreElastic fibre ROMROM--Blend of these two factors.Blend of these two factors.

Total Resistance of fibresTotal Resistance of fibres 10% tendon/47% ligament/41% fascia.10% tendon/47% ligament/41% fascia.

Thus connective tissue must be fully stretchedThus connective tissue must be fully stretched

with the muscle relaxed for flexibility to bewith the muscle relaxed for flexibility to beoptimally developed.optimally developed.


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AfterTraining versusAfterTraining versus

DevelopmentalStretchingDevelopmentalStretching Once the muscle fiber is at its maximum resting length (allOnce the muscle fiber is at its maximum resting length (all

the sarcomeres are fully stretched), additional stretchingthe sarcomeres are fully stretched), additional stretchingplaces force on the surrounding connective tissue (see Asplaces force on the surrounding connective tissue (see Asthe tension increases, the collagen fibers in the connectivethe tension increases, the collagen fibers in the connectivetissue align themselves along the same line of force as thetissue align themselves along the same line of force as the

tension.tension.

Hence when you stretch, the muscle fiber is pulled out to itsHence when you stretch, the muscle fiber is pulled out to itsfull length sarcomere by sarcomere, and then the connectivefull length sarcomere by sarcomere, and then the connectivetissue takes up the remaining slack. When this occurs, ittissue takes up the remaining slack. When this occurs, ithelps to realign any disorganized fibers in the direction of thehelps to realign any disorganized fibers in the direction of the

tension. This realignment is what helps to rehabilitatetension. This realignment is what helps to rehabilitatescarred tissue back to health.scarred tissue back to health.

From Book Science of StretchingFrom Book Science of StretchingAlterAlter


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DynamicWU (or Stretches?)DynamicWU (or Stretches?)


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Screening or

Functional Flexibilityor Dynamic

Movement or Full

Range Movement orSquatting with a

stick above ones

head.


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SCREENING

From AFL Study

on predicting

hamstringsthrough

screening.


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PNFPNF2 Receptors2 Receptors

1)1) Golgi Tendon Organs: Sensitive to changes in tension.Golgi Tendon Organs: Sensitive to changes in tension.2)2) Muscle Spindles: Senstive to change in length.Muscle Spindles: Senstive to change in length.

AUTOGENIC INHIBITIONAUTOGENIC INHIBITION

Isometric contraction of a muscle placed on a slight stretch isIsometric contraction of a muscle placed on a slight stretch isfollowed byfollowed byrelaxation.relaxation.

Inhibition which is mediated by afferent fibers from a stretchedInhibition which is mediated by afferent fibers from a stretched muscle andmuscle andacting on the alpah motorneurons supplying that muscle,thus causacting on the alpah motorneurons supplying that muscle,thus causing iting it

to relax.to relax.

Ruch and Patton 1965Ruch and Patton 1965

FOR: Balance/Strength/ROM/CoFOR: Balance/Strength/ROM/Co--ordination etc etcordination etc etc

AGAINST: ? Dangerous/Valsalva?/AGAINST: ? Dangerous/Valsalva?/

Challenges to the theory of PNF and Golgi Organs onlyChallenges to the theory of PNF and Golgi Organs onlymomentarily depressed after a contraction?momentarily depressed after a contraction?


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PNFPNF

The holdThe hold--relax or contract/relaxrelax or contract/relax

After assuming an initial passive stretch, the muscle being streAfter assuming an initial passive stretch, the muscle being stretched is isometricallytched is isometricallycontracted for 7contracted for 7--15 seconds, after which the muscle is briefly relaxed for 215 seconds, after which the muscle is briefly relaxed for 2 --3 seconds, and3 seconds, and

then immediately subjected to a passive stretch which stretchesthen immediately subjected to a passive stretch which stretchesthe muscle even furtherthe muscle even furtherthan the initial passive stretch. This passive stretch is heldthan the initial passive stretch. This passive stretch is heldfor 10for 10--15 seconds. The15 seconds. The

muscle is then relaxed for 20 seconds before performing anothermuscle is then relaxed for 20 seconds before performing anotherPNF technique.PNF technique.

The holdThe hold--relaxrelax--contract CRACcontract CRAC

This technique is also called the contractThis technique is also called the contract--relaxrelax--contract, and the contractcontract, and the contract--relaxrelax--

antagonistantagonist--contract (or CRAC). It involves performing two isometric contraccontract (or CRAC). It involves performing two isometric contrac tions: first of thetions: first of theagonists, then, of the antagonists. The first part is similar toagonists, then, of the antagonists. The first part is similar to the holdthe hold--relax where, afterrelax where, after

assuming an initial passive stretch, the stretched muscle is isoassuming an initial passive stretch, the stretched muscle is isometrically contracted for 7metrically contracted for 7--15 seconds. Then the muscle is relaxed while its antagonist imme15 seconds. Then the muscle is relaxed while its antagonist immediately performs andiately performs an

isometric contraction that is held for 7isometric contraction that is held for 7--15 seconds. The muscles are then relaxed for 2015 seconds. The muscles are then relaxed for 20

seconds before performing another PNF technique.seconds before performing another PNF technique.

The holdThe hold--relaxrelax--swingswing

Bounce after contractBounce after contract....


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Contemporaryview proposesthat PNFContemporaryview proposesthat PNF

stretchinginfluences thepoint atwhichstretchinginfluences thepoint atwhich

stretchis perceivedor toleratedstretchis perceivedor tolerated

Sports Med. 2006;36(11):929Sports Med. 2006;36(11):929--39.39.

SharmanSharman

Proprioceptive neuromuscular facilitation stretching : mechanismProprioceptive neuromuscular facilitation stretching : mechanisms ands andclinical implications.clinical implications.

PNF stretching is positioned in the literature as the most effecPNF stretching is positioned in the literature as the most effec tive stretching technique when the aim is totive stretching technique when the aim is toincrease ROM, particularly in respect to shortincrease ROM, particularly in respect to short --term changes in ROM.term changes in ROM.

3 seconds at no more than 20% of a maximum voluntary contraction3 seconds at no more than 20% of a maximum voluntary contraction . The greatest changes in ROM generally. The greatest changes in ROM generallyoccur after the first repetition and in order to achieve more laoccur after the first repetition and in order to achieve more la sting changes in ROM, PNF stretching needs tosting changes in ROM, PNF stretching needs tobe performed once or twice per week.be performed once or twice per week.

PNF stretching has traditionally been attributed to autogenic anPNF stretching has traditionally been attributed to autogenic an d/or reciprocal inhibition.d/or reciprocal inhibition.

Instead, and in the absence of a biomechanical explanation, theInstead, and in the absence of a biomechanical explanation, the contemporary view proposes that PNFcontemporary view proposes that PNFstretching influences the point at which stretch is perceived orstretching influences the point at which stretch is perceived ortolerated.tolerated.

The mechanism(s) underpinning the change in stretch perception oThe mechanism(s) underpinning the change in stretch perception or tolerance are not known, although painr tolerance are not known, although painmodulation has been suggested.modulation has been suggested.


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ActiveIsolated Stretching(AIS)ActiveIsolated Stretching(AIS)

ContractContract--RelaxRelax--Antagonist ContractAntagonist Contract--Relax or CRACRRelax or CRACR

2 Secs Hold

< Stretch Reflex?


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Acute Effects of Static and ProprioceptiveAcute Effects of Static and Proprioceptive

Neuromuscular Facilitation Stretching onNeuromuscular Facilitation Stretching on

Muscle Strength and Power Output.Muscle Strength and Power Output.

J Athl Train. 2005 Jun;40(2):94J Athl Train. 2005 Jun;40(2):94--103.103.

Conclusions: Both static and proprioceptiveConclusions: Both static and proprioceptive

neuromuscular facilitation stretching causedneuromuscular facilitation stretching caused

similar deficits in strength, power output, andsimilar deficits in strength, power output, andmuscle activation at both slow (60 degrees .s)muscle activation at both slow (60 degrees .s)

and fast (300 degrees .s) velocities.and fast (300 degrees .s) velocities.


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Injuries in Australian Army RecruitsInjuries in Australian Army Recruits

Military Medicine, Vol. 162, pp. 481Military Medicine, Vol. 162, pp. 481--483, 1997483, 1997

During the 11During the 11--week period, 40 actual workouts were completed by theweek period, 40 actual workouts were completed by therecruits, adding up to 50 total hours of hard physical effort. Trecruits, adding up to 50 total hours of hard physical effort. Thehe

training was divided into route marching (10 hours), running (10training was divided into route marching (10 hours), running (10.5.5hours), obstaclehours), obstacle--course workouts (12.5 hours), circuit training (7.5course workouts (12.5 hours), circuit training (7.5

hours), swimming (four hours), and battle training (5.5 hours).hours), swimming (four hours), and battle training (5.5 hours).

333 lower333 lower--limb injuries were recordedlimb injuries were recorded175 in the control group and 158175 in the control group and 158in the stretching recruits, which represented an overall injuryin the stretching recruits, which represented an overall injury rate ofrate of

5.5 injuries per 1000 hours of training5.5 injuries per 1000 hours of training

Stretching during warmStretching during warm--up had no statistically significant effect on the riskup had no statistically significant effect on the risk

of injury, either for softof injury, either for soft--tissue problems or bony disorderstissue problems or bony disorders..


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LallyLally, D. A. (1994)., D. A. (1994). StretchingStretchingand injury in distance runners.and injury in distance runners.

Medicine and Science in Sports and ExerciseMedicine and Science in Sports and Exercise

47% of all male runners who stretched regularly were injured dur47% of all male runners who stretched regularly were injured duringinga onea one--year periodyear period

33% of male runners who didn't stretch were hurt33% of male runners who didn't stretch were hurt

When Lally threw the males with previous injuries out of his stuWhen Lally threw the males with previous injuries out of his study,dy,

things were still bad for the stretchers, who had a 33% greaterthings were still bad for the stretchers, who had a 33% greater risk ofrisk ofinjury, compared to noninjury, compared to non--stretching runners.stretching runners.

lady stretchers had the same rate of injury as lady nonlady stretchers had the same rate of injury as lady non--stretchers.stretchers.

* Females* Females.( ACL comment).( ACL comment)

However, those athletes who stretched after their workouts actuaHowever, those athletes who stretched after their workouts actuallyllyenjoyed a lower risk of getting hurt.enjoyed a lower risk of getting hurt.


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Dynamic vs. staticDynamic vs. static--stretching warm up: thestretching warm up: the

effect on power and agility performanceeffect on power and agility performance

United States Military Academy, West Point, USA.United States Military Academy, West Point, USA.

On 3 consecutive days, subjects performed 1 of the 2 warm upOn 3 consecutive days, subjects performed 1 of the 2 warm uproutines (DWU or SWU) or performed no warm up (NWU). The 3routines (DWU or SWU) or performed no warm up (NWU). The 3warm up protocols lasted 10 minutes each and werewarm up protocols lasted 10 minutes each and were

counterbalanced to avoid carryover effects.counterbalanced to avoid carryover effects.

After 1After 1--2 minutes of recovery, subjects performed 3 tests of2 minutes of recovery, subjects performed 3 tests ofpower or agility. The order of the performance tests (Tpower or agility. The order of the performance tests (T--shuttleshuttlerun, underhand medicine ball throw for distance, and 5run, underhand medicine ball throw for distance, and 5 --stepstep

jump) also was counterbalanced.jump) also was counterbalanced.

Results of this study indicate a relative performanceResults of this study indicate a relative performanceenhancement with the DWU, warm up routines that use staticenhancement with the DWU, warm up routines that use staticstretching as a standstretching as a stand--alone activity should be reassessed.alone activity should be reassessed.


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Flexibility enhancement with vibration:Flexibility enhancement with vibration:

Acute and longAcute and long--term.term.

Med Sci Sports Exerc. 2006 Apr;38(4):720Med Sci Sports Exerc. 2006 Apr;38(4):720--5.5.

CONCLUSION: This study showed that vibration can beCONCLUSION: This study showed that vibration can be

a promising means of increasing range of motiona promising means of increasing range of motion

beyond that obtained with static stretching in highlybeyond that obtained with static stretching in highlytrained male gymnasts.trained male gymnasts.


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The effectiveness of 3 stretching techniquesThe effectiveness of 3 stretching techniques

on hamstring flexibility using consistenton hamstring flexibility using consistent

stretching parameters.stretching parameters.

J Strength Cond Res. 2005 Feb;19(1):27J Strength Cond Res. 2005 Feb;19(1):27--3232

The criterion for subject inclusion was tight hamstrings as defiThe criterion for subject inclusion was tight hamstrings as defined by aned by a

Group 1 (n = 5) was selfGroup 1 (n = 5) was self--stretching, group 2 (n = 5) was static stretching, groupstretching, group 2 (n = 5) was static stretching, group3 (n = 5) was proprioceptive neuromuscular facilitation incorpor3 (n = 5) was proprioceptive neuromuscular facilitation incorpor ating the theoryating the theoryof reciprocal inhibition (PNFof reciprocal inhibition (PNF--R), and group 4 (n = 4) was control.R), and group 4 (n = 4) was control.

Each group received the same stretching dose of a single 30Each group received the same stretching dose of a single 30--second stretch 3second stretch 3days per week for 4 weeks. Knee extension angle was measured befdays per week for 4 weeks. Knee extension angle was measured before the startore the startof the stretching program, at 2 weeks, and at 4 weeks.. These daof the stretching program, at 2 weeks, and at 4 weeks.. These data indicate thatta indicate thatstatic stretching 1 repetition for 30 seconds 3 days per week instatic stretching 1 repetition for 30 seconds 3 days per week increased hamstringcreased hamstringlength in young healthy subjects. These data also suggest that alength in young healthy subjects. These data also suggest that active selfctive self--stretching and PNFstretching and PNF--R stretching 1 repetition for 30 seconds 3 days per week isR stretching 1 repetition for 30 seconds 3 days per week isnot sufficient to significantly increase hamstring length in thinot sufficient to significantly increase hamstring length in this population.s population.


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The effect of time on static stretch on theThe effect of time on static stretch on the

flexibility of the hamstring musclesflexibility of the hamstring muscles

Phys Ther. 1994 Sep;74(9):845Phys Ther. 1994 Sep;74(9):845--50;50;

FiftyFifty--seven subjects (40 men, 17 women), ranging in age from 21 to 37seven subjects (40 men, 17 women), ranging in age from 21 to 37years and with limited hamstring muscle flexibility (ie, 30 degryears and with limited hamstring muscle flexibility (ie, 30 degrees loss ofees loss ofknee extension measured with femur held at 90 degrees of hip fleknee extension measured with femur held at 90 degrees of hip flexion),xion),

were randomly assigned to one of four groups.were randomly assigned to one of four groups.

Three groups stretched 5 days per week for 15, 30, and 60 secondThree groups stretched 5 days per week for 15, 30, and 60 seconds,s,respectively. The fourth group, which served as a control group,respectively. The fourth group, which served as a control group, did notdid not

stretch.stretch.

CONCLUSION AND DISCUSSION. The results of this study suggest thaCONCLUSION AND DISCUSSION. The results of this study suggest that at aduration of 30 seconds is an effective time of stretching for enduration of 30 seconds is an effective time of stretching for en hancing thehancing the

flexibility of the hamstring muscles. Given the information thatflexibility of the hamstring muscles. Given the information that

no increase inno increase in

flexibility of the hamstring muscles occurred by increasing theflexibility of the hamstring muscles occurred by increasing the duration ofduration ofstretching from 30 to 60 seconds, the use of the longer durationstretching from 30 to 60 seconds, the use of the longer duration of stretchingof stretching

for an acute effect must be questionedfor an acute effect must be questioned