Go to the previous, next chapter. The different types of stretching are: Ballistic stretching uses the momentum of a moving body or a limb in anattempt to force it beyond its normal range of motion. This isstretching, or "warming up", by bouncing into (or out of) a stretchedposition, using the stretched muscles as a spring which pulls you out ofthe stretched position. (e.g. bouncing down repeatedly to touch yourtoes.) This type of stretching is not considered useful and can lead toinjury. It does not allow your muscles to adjust to, and relax in, thestretched position. It may instead cause them to tighten up byrepeatedly activating the stretch reflex (see section The Stretch Reflex). Dynamic stretching, according to Kurz, "involves moving partsof your body and gradually increasing reach, speed of movement, orboth." Do not confuse dynamic stretching with ballistic stretching!Dynamic stretching consists of controlled leg and arm swings that takeyou (gently!) to the limits of your range of motion. Ballisticstretches involve trying to force a part of the body beyond itsrange of motion. In dynamic stretches, there are no bounces or "jerky"movements. An example of dynamic stretching would be slow, controlledleg swings, arm swings, or torso twists. Dynamic stretching improves dynamic flexibility and is quite useful aspart of your warm-up for an active or aerobic workout (such as a danceor martial-arts class). See section Warming Up. According to Kurz, dynamic stretching exercises should be performedin sets of 8-12 repetitions. Be sure to stop when and if you feeltired. Tired muscles have less elasticity which decreases the range ofmotion used in your movements. Continuing to exercise when you aretired serves only to reset the nervous control of your muscle length atthe reduced range of motion used in the exercise (and will cause a lossof flexibility). Once you attain a maximal range of motion for a jointin any direction you should stop doing that movement during thatworkout. Tired and overworked muscles won't attain a full range ofmotion and the muscle's kinesthetic memory will remember the repeatedshorted range of motion, which you will then have to overcome beforeyou can make further progress. Active stretching is also referred to as static-activestretching. An active stretch is one where you assume a position andthen hold it there with no assistance other than using the strength ofyour agonist muscles (see section Cooperating Muscle Groups). For example,bringing your leg up high and then holding it there without anything(other than your leg muscles themselves) to keep the leg in thatextended position. The tension of the agonists in an active stretchhelps to relax the muscles being stretched (the antagonists) byreciprocal inhibition (see section Reciprocal Inhibition). Active stretching increases active flexibility and strengthens theagonistic muscles. Active stretches are usually quite difficult tohold and maintain for more than 10 seconds and rarely need to be heldany longer than 15 seconds.
Just as there are different types of flexibility, there are alsodifferent types of stretching. Stretches are either dynamic (meaningthey involve motion) or static (meaning they involve no motion).Dynamic stretches affect dynamic flexibility and static stretches affectstatic flexibility (and dynamic flexibility to some degree).Ballistic Stretching
Dynamic Stretching
Active Stretching
Many of the movements (or stretches) found in various forms of yoga areactive stretches.
Passive Stretching
- Static Stretching: (next section)
- Active Stretching: (previous section)
- Types of Stretching: (beginning of chapter)
Passive stretching is also referred to as relaxed stretching,and as static-passive stretching. A passive stretch is one whereyou assume a position and hold it with some other part of your body,or with the assistance of a partner or some other apparatus. For example,bringing your leg up high and then holding it there with your hand. Thesplits is an example of a passive stretch (in this case the floor isthe "apparatus" that you use to maintain your extended position).
Slow, relaxed stretching is useful in relieving spasms in muscles thatare healing after an injury. Obviously, you should check with yourdoctor first to see if it is okay to attempt to stretch the injuredmuscles (see section Pain and Discomfort).
Relaxed stretching is also very good for "cooling down" after a workoutand helps reduce post-workout muscle fatigue, and soreness.See section Cooling Down.
Static Stretching
- Isometric Stretching: (next section)
- Passive Stretching: (previous section)
- Types of Stretching: (beginning of chapter)
Many people use the term "passive stretching" and "static stretching"interchangeably. However, there are a number of people who make adistinction between the two. According to M. Alter,Static stretching consists of stretching a muscle (or group of muscles)to its farthest point and then maintaining or holding that position,whereas Passive stretching consists of a relaxed person whois relaxed (passive) while some external force (either a person oran apparatus) brings the joint through its range of motion.
Notice that the definition of passive stretching given in theprevious section encompasses both of the above definitions.Throughout this document, when the term static stretchingor passive stretching is used, its intended meaning isthe definition of passive stretching as described in the previoussection. You should be aware of these alternative meanings, however,when looking at other references on stretching.
Isometric Stretching
- PNF Stretching: (next section)
- Static Stretching: (previous section)
- Types of Stretching: (beginning of chapter)
Isometric stretching is a type of static stretching (meaning itdoes not use motion) which involves the resistance of muscle groupsthrough isometric contractions (tensing) of the stretched muscles(see section Types of Muscle Contractions). The use of isometric stretchingis one of the fastest ways to develop increased static-passiveflexibility and is much more effective than either passive stretching oractive stretching alone. Isometric stretches also help to developstrength in the "tensed" muscles (which helps to develop static-activeflexibility), and seems to decrease the amount of pain usuallyassociated with stretching.
The most common ways to provide the needed resistance for an isometricstretch are to apply resistance manually to one's own limbs, to have apartner apply the resistance, or to use an apparatus such as a wall(or the floor) to provide resistance.
An example of manual resistance would be holding onto the ball of yourfoot to keep it from flexing while you are using the muscles of yourcalf to try and straighten your instep so that the toes are pointed.
An example of using a partner to provide resistance would be having apartner hold your leg up high (and keep it there) while you attempt toforce your leg back down to the ground.
An example of using the wall to provide resistance would be the wellknown "push-the-wall" calf-stretch where you are actively attempting tomove the wall (even though you know you can't).
Isometric stretching is not recommended for children andadolescents whose bones are still growing. These people are usuallyalready flexible enough that the strong stretches produced by theisometric contraction have a much higher risk of damaging tendons andconnective tissue. Kurz strongly recommends preceding any isometricstretch of a muscle with dynamic strength training for the muscle to bestretched. A full session of isometric stretching makes a lot of demandson the muscles being stretched and should not be performed more thanonce per day for a given group of muscles (ideally, no more than onceevery 36 hours).
The proper way to perform an isometric stretch is as follows:
- Assume the position of a passive stretch for the desired muscle.
- Next, tense the stretched muscle for 7-15 seconds (resisting againstsome force that will not move, like the floor or a partner).
- Finally, relax the muscle for at least 20 seconds.
Some people seem to recommend holding the isometric contraction forlonger than 15 seconds, but according to SynerStretch (thevideotape), research has shown that this is not necessary. So you mightas well make your stretching routine less time consuming.
- How Isometric Stretching Works
How Isometric Stretching Works
- Isometric Stretching: (beginning of section)
Recall from our previous discussion (see section How Muscles Contract)that there is no such thing as a partially contracted muscle fiber:when a muscle is contracted, some of the fibers contract and someremain at rest (more fibers are recruited as the load on the muscleincreases). Similarly, when a muscle is stretched, some of thefibers are elongated and some remain at rest (see section What Happens When You Stretch). During an isometric contraction, some of theresting fibers are being pulled upon from both ends by the musclesthat are contracting. The result is that some of those restingfibers stretch!
Normally, the handful of fibers that stretch during an isometriccontraction are not very significant. The true effectiveness of theisometric contraction occurs when a muscle that is already in astretched position is subjected to an isometric contraction. In thiscase, some of the muscle fibers are already stretched before thecontraction, and, if held long enough, the initial passive stretchovercomes the stretch reflex (see section The Stretch Reflex) and triggersthe lengthening reaction (see section The Lengthening Reaction), inhibitingthe stretched fibers from contracting. At this point, according toSynerStretch, when you isometrically contracted, some restingfibers would contract and some resting fibers would stretch.Furthermore, many of the fibers already stretching may be preventedfrom contracting by the inverse myotatic reflex (the lengtheningreaction) and would stretch even more. When the isometric contractionis completed, the contracting fibers return to their resting length butthe stretched fibers would remember their stretched length and (for aperiod of time) retain the ability to elongate past their previouslimit. This enables the entire muscle to stretch beyonds its initialmaximum and results in increased flexibility.
The reason that the stretched fibers develop and retain the ability tostretch beyond their normal limit during an isometric stretch has to dowith the muscle spindles (see section Proprioceptors): The signal whichtells the muscle to contract voluntarily, also tells the musclespindle's (intrafusal) muscle fibers to shorten, increasing sensitivityof the stretch reflex. This mechanism normally maintains thesensitivity of the muscle spindle as the muscle shortens duringcontraction. This allows the muscle spindles to habituate (becomeaccustomed) to an even further-lengthened position.
PNF Stretching
- Isometric Stretching: (previous section)
- Types of Stretching: (beginning of chapter)
PNF stretching is currently the fastest and most effective wayknown to increase static-passive flexibility. PNF is an acronymfor proprioceptive neuromuscular facilitation. It is notreally a type of stretching but is a technique of combining passivestretching (see section Passive Stretching) and isometric stretching(see section Isometric Stretching) in order to achieve maximum staticflexibility. Actually, the term PNF stretching is itself a misnomer.PNF was initially developed as a method of rehabilitating strokevictims. PNF refers to any of several post-isometric relaxationstretching techniques in which a muscle group is passively stretched,then contracts isometrically against resistance while in thestretched position, and then is passively stretched again throughthe resulting increased range of motion. PNF stretching usuallyemploys the use of a partner to provide resistance against theisometric contraction and then later to passively take the jointthrough its increased range of motion. It may be performed, however,without a partner, although it is usually more effective with apartner's assistance.
Most PNF stretching techniques employ isometric agonistcontraction/relaxation where the stretched muscles are contractedisometrically and then relaxed. Some PNF techniques also employisometric antagonist contraction where the antagonists of thestretched muscles are contracted. In all cases, it is important to notethat the stretched muscle should be rested (and relaxed) for at least 20seconds before performing another PNF technique. The most common PNFstretching techniques are:
- the hold-relax
- This technique is also called the contract-relax. After assumingan initial passive stretch, the muscle being stretched is isometricallycontracted for 7-15 seconds, after which the muscle is briefly relaxedfor 2-3 seconds, and then immediately subjected to a passive stretchwhich stretches the muscle even further than the initial passivestretch. This final passive stretch is held for 10-15 seconds. Themuscle is then relaxed for 20 seconds before performing another PNFtechnique.
- the hold-relax-contract
- This technique is also called the contract-relax-contract, and thecontract-relax-antagonist-contract (or CRAC). It involvesperforming two isometric contractions: first of the agonists, then, ofthe antagonists. The first part is similar to the hold-relax where,after assuming an initial passive stretch, the stretched muscle isisometrically contracted for 7-15 seconds. Then the muscle is relaxedwhile its antagonist immediately performs an isometric contraction thatis held for 7-15 seconds. The muscles are then relaxed for 20 secondsbefore performing another PNF technique.
- the hold-relax-swing
- This technique (and a similar technique called the hold-relax-bounce)actually involves the use of dynamic or ballistic stretches inconjunction with static and isometric stretches. It is veryrisky, and is successfully used only by the most advanced of athletesand dancers that have managed to achieve a high level of controlover their muscle stretch reflex (see section The Stretch Reflex). Itis similar to the hold-relax technique except that a dynamic orballistic stretch is employed in place of the final passive stretch.
Notice that in the hold-relax-contract, there is no final passivestretch. It is replaced by the antagonist-contraction which, viareciprocal inhibition (see section Reciprocal Inhibition), serves to relaxand further stretch the muscle that was subjected to the initial passivestretch. Because there is no final passive stretch, this PNF techniqueis considered one of the safest PNF techniques to perform (it is lesslikely to result in torn muscle tissue). Some people like to make thetechnique even more intense by adding the final passive stretch afterthe second isometric contraction. Although this can result in greaterflexibility gains, it also increases the likelihood of injury.
Even more risky are dynamic and ballistic PNF stretching techniqueslike the hold-relax-swing, and the hold-relax-bounce. If you arenot a professional athlete or dancer, you probably have no businessattempting either of these techniques (the likelihood of injury isjust too great). Even professionals should not attempt thesetechniques without the guidance of a professional coach or trainingadvisor. These two techniques have the greatest potential for rapidflexibility gains, but only when performed by people who have asufficiently high level of control of the stretch reflex in themuscles that are being stretched.
Like isometric stretching (see section Isometric Stretching), PNFstretching is also not recommended for children and people whosebones are still growing (for the same reasons. Also like isometricstretching, PNF stretching helps strengthen the muscles that arecontracted and therefore is good for increasing active flexibilityas well as passive flexibility. Furthermore, as with isometricstretching, PNF stretching is very strenuous and should be performedfor a given muscle group no more than once per day (ideally, nomore than once per 36 hour period).
The initial recommended procedure for PNF stretching is to perform thedesired PNF technique 3-5 times for a given muscle group (resting 20seconds between each repetition). However, HFLTA cites a 1987study whose results suggest that performing 3-5 repetitions of a PNFtechnique for a given muscle group is not necessarily any more effectivethan performing the technique only once. As a result, in order todecrease the amount of time taken up by your stretching routine (withoutdecreasing its effectiveness), HFLTA recommends performing onlyone PNF technique per muscle group stretched in a given stretchingsession.
- How PNF Stretching Works
How PNF Stretching Works
- PNF Stretching: (beginning of section)
The isometric contraction of the stretched muscle accomplishes severalthings:
- As explained previously (see section How Isometric Stretching Works),it helps to train the stretch receptors of the muscle spindle toimmediately accommodate a greater muscle length.
- The intense muscle contraction, and the fact that it is maintained for aperiod of time, serves to fatigue many of the fast-twitch fibers of thecontracting muscles (see section Fast and Slow Muscle Fibers). This makesit harder for the fatigued muscle fibers to contract in resistance to asubsequent stretch (see section The Stretch Reflex).
- The tension generated by the contraction activates the golgi tendonorgan (see section Proprioceptors), which inhibits contraction of the musclevia the lengthening reaction (see section The Lengthening Reaction).Voluntary contraction during a stretch increases tension on the muscle,activating the golgi tendon organs more than the stretch alone. So,when the voluntary contraction is stopped, the muscle is even moreinhibited from contracting against a subsequent stretch.
PNF stretching techniques take advantage of the sudden "vulnerability"of the muscle and its increased range of motion by using the period oftime immediately following the isometric contraction to train thestretch receptors to get used to this new, increased, range of musclelength. This is what the final passive (or in some cases, dynamic)stretch accomplishes.
Go to the previous, next chapter.
