STRETCHING

INTRODUCTION:

 Stretching is a form of physical exercise in which a specific muscle or tendon (or muscle group) is deliberately flexed or stretched in order to improve the muscle's felt elasticity and achieve comfortable muscle tone. The result is a feeling of increased muscle control, flexibility, and range of motion. Stretching is also used therapeutically to alleviate cramps and to improve function in daily activities by increasing range of motion.

In its most basic form, stretching is a natural and instinctive activity; it is performed by humans and many other animals. It can be accompanied by yawning. Stretching often occurs instinctively after waking from sleep, after long periods of inactivity, or after exiting confined spaces and areas.

Increasing flexibility through stretching is one of the basic tenets of physical fitness. It is common for athletes to stretch before (for warming up) and after exercise in an attempt to reduce risk of injury and increase performance.

Stretching can be dangerous when performed incorrectly. There are many techniques for stretching in general, but depending on which muscle group is being stretched, some techniques may be ineffective or detrimental, even to the point of causing hypermobility, instability, or permanent damage to the tendons, ligaments, and muscle fiber. The physiological nature of stretching and theories about the effect of various techniques are therefore subject to heavy inquiry.

Though static stretching is a part of some pre and post-workout routines, a review article that was published in January 2020 by the Scandinavian Society of Clinical Physiology and Nuclear Medicine, indicated that pre-exercise static stretching did in-fact reduce an individuals overall muscular strength and maximal performance. Furthermore, theses findings present a uniform effect, regardless of an individuals age, gender, or training status. For this reason, an active dynamic warm-up is recommended before exercise in place of static stretching.

 

Physiology

Studies have shed light on the function, in stretching, of a large protein within the myofibrils of skeletal muscles named titin. A study performed by Magid and Law demonstrated that the origin of passive muscle tension (which occurs during stretching) is actually within the myofibrils, not extracellularly as had previously been supposed. Due to neurological safeguards against injury such as the Golgi tendon reflex, it is normally impossible for adults to stretch most muscle groups to their fullest length without training due to the activation of muscle antagonists as the muscle reaches the limit of its normal range of motion.

Types of stretches

Stretches can be either static or dynamic, where static stretches are performed while stationary and dynamic stretches involve movement of the muscle during the stretch. Stretches can also be active or passive, where active stretches use internal forces generated by the body to perform a stretch and passive stretches involve forces from external objects or people to facilitate the stretch. Stretches can involve both passive and active components.

• Assisted stretching may be performed when the athlete is unable to stretch optimally independently. For example, during cramping of the hamstrings, assistance in stretching out the muscles may help.

Dynamic stretching

Dynamic stretching is a movement based stretch aimed on increasing blood flow throughout the body while also loosening up the muscle fibers. Standard dynamic stretches typically involve slow and controlled active contraction of muscles. An example of such a dynamic stretch are lunges. Another form of dynamic stretching is ballistic stretching, which is an active stretch that involves bouncing or swinging back and forth at a high speed in order to take a muscle beyond its typical range of motion using momentum. Ballistic stretching may cause damage to the joints.

Static stretching

The simplest static stretches are static-passive stretches, according to research findings, this brings the joint to its end range of motion and hold it there using external forces. There are more advanced forms of static stretching, such as proprioceptive neuromuscular facilitation (PNF), which involves both active muscle contractions and passive external forces. PNF stretching may involve contracting either the antagonist muscles, agonist muscles, or both (CRAC).

Effectiveness

 

Stretching has been found both effective, and ineffective based on its application for treatment.

Although many people engage in stretching before or after exercise, the medical evidence has shown this has no meaningful benefit in preventing specifically muscle soreness. It may reduce the lactic acid build up in the muscles, making your next workout more bearable.

Stretching does not appear to reduce the risk of injury during exercises, except perhaps for runners. There is some evidence that pre-exercise stretching may increase athletes' range of movement.

There are different positives and negatives for the two main types of stretching: static and dynamic. Static stretching is better at creating a more intense stretch because it is able to isolate a muscle group better. But this intense of a stretch may hinder one's athletic performance because the muscle is being over stretched while held in this position and, once the tension is released, the muscle will tend to tighten up and may actually become weaker than it was previously. Also, the longer the duration of static stretching, the more exhausted the muscle becomes. This type of stretching has been shown to have negative results on athletic performance within the categories of power and speed. However to be able to do usual daily activities, a certain amount of range of motion is needed from each muscle. For example "The calf muscles are one of the muscle groups that have the most need for adequate flexibility since they are deeply related to normal lower limb function. When the goal is to increase flexibility, the most commonly used technique is stretching". Chronic static stretching was shown to increase range of motion of Dorsiflexion or bringing ones foot closer to their shin by an average of 5.17 degrees in healthy individuals versus 3.77 degrees when solely using ballistic stretching.

Dynamic stretching, because it is movement-based, may not isolate the muscle group as well or have as intense of a stretch, but it is better at increasing the circulation of blood flow throughout the body, which in turn increases the amount of oxygen able to be used for an athletic performance. This type of stretching has shown better results on athletic performances of power and speed, when compared to static stretching.

However, both of these types of stretching have been shown to have a positive impact on flexibility over time by increasing muscle and joint elasticity, thus increasing the depth and range of motion an athlete is able to reach. This is evident in the experiment "Acute effects of duration on sprint performance of adolescent football players". In this experiment, football players were put through different stretching durations of static and dynamic stretching to test their effects. They were tested on maximum sprinting ability and overall change in flexibility. Both static and dynamic stretching had a positive impact on flexibility but, whereas dynamic stretching had no impact on sprint times, static stretching had a negative result, worsening the time the participants were able to sprint the distance in. While the duration of stretching for dynamic had no impact on the overall results, the longer the stretch was held for static, the worse the results got, showing that the longer the duration of stretching held, the weaker the muscle became.

Stretching tool

• BOSU(Bionic Oscillatory Stabilization Unit)
• Flexcushion
• Foam roller
• Stretch Band

Types of Stretching

Just as there are different types of flexibility, there are also different types of stretching. Stretches are either dynamic (meaning they involve motion) or static (meaning they involve no motion). Dynamic stretches affect dynamic flexibility and static stretches affect static flexibility (and dynamic flexibility to some degree).

The different types of stretching are:

1. ballistic stretching
2. dynamic stretching
3. active stretching
4. passive (or relaxed) stretching
5. static stretching
6. isometric stretching
7. PNF stretching

Ballistic Stretching

Ballistic stretching uses the momentum of a moving body or a limb in an attempt to force it beyond its normal range of motion. This is stretching, or "warming up", by bouncing into (or out of) a stretched position, using the stretched muscles as a spring which pulls you out of the stretched position. (e.g. bouncing down repeatedly to touch your toes.) This type of stretching is not considered useful and can lead to injury. It does not allow your muscles to adjust to, and relax in, the stretched position. It may instead cause them to tighten up by repeatedly activating the stretch reflex .

Dynamic Stretching

Dynamic stretching, according to Kurz, "involves moving parts of your body and gradually increasing reach, speed of movement, or both." Do not confuse dynamic stretching with ballistic stretching! Dynamic stretching consists of controlled leg and arm swings that take you (gently!) to the limits of your range of motion. Ballistic stretches involve trying to force a part of the body beyond its range of motion. In dynamic stretches, there are no bounces or "jerky" movements. An example of dynamic stretching would be slow, controlled leg swings, arm swings, or torso twists.

Dynamic stretching improves dynamic flexibility and is quite useful as part of your warm-up for an active or aerobic workout (such as a dance or martial-arts class).

According to Kurz, dynamic stretching exercises should be performed in sets of 8-12 repetitions. Be sure to stop when and if you feel tired. Tired muscles have less elasticity which decreases the range of motion used in your movements. Continuing to exercise when you are tired serves only to reset the nervous control of your muscle length at the reduced range of motion used in the exercise (and will cause a loss of flexibility). Once you attain a maximal range of motion for a joint in any direction you should stop doing that movement during that workout. Tired and overworked muscles won't attain a full range of motion and the muscle's kinesthetic memory will remember the repeated shorted range of motion, which you will then have to overcome before you can make further progress.

Active Stretching

Active stretching is also referred to as static-active stretching. An active stretch is one where you assume a position and then hold it there with no assistance other than using the strength of your 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 that extended position. The tension of the agonists in an active stretch helps to relax the muscles being stretched (the antagonists) by reciprocal inhibition (see section Reciprocal Inhibition).

Active stretching increases active flexibility and strengthens the agonistic muscles. Active stretches are usually quite difficult to hold and maintain for more than 10 seconds and rarely need to be held any longer than 15 seconds.

Many of the movements (or stretches) found in various forms of yoga are active stretches.

Passive Stretching

Passive stretching is also referred to as relaxed stretching, and as static-passive stretching. A passive stretch is one where you 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. The splits is an example of a passive stretch (in this case the floor is the "apparatus" that you use to maintain your extended position).

Slow, relaxed stretching is useful in relieving spasms in muscles that are healing after an injury. Obviously, you should check with your doctor first to see if it is okay to attempt to stretch the injured muscles (see section Pain and Discomfort).

Relaxed stretching is also very good for "cooling down" after a workout and helps reduce post-workout muscle fatigue, and soreness. See section Cooling Down.

Static Stretching

Many people use the term "passive stretching" and "static stretching" interchangeably. However, there are a number of people who make a distinction 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 who is relaxed (passive) while some external force (either a person or an apparatus) brings the joint through its range of motion.

Notice that the definition of passive stretching given in the previous section encompasses both of the above definitions. Throughout this document, when the term static stretching or passive stretching is used, its intended meaning is the definition of passive stretching as described in the previous section. You should be aware of these alternative meanings, however, when looking at other references on stretching.

Isometric Stretching

Isometric stretching is a type of static stretching (meaning it does not use motion) which involves the resistance of muscle groups through isometric contractions (tensing) of the stretched muscles (see section Types of Muscle Contractions). The use of isometric stretching is one of the fastest ways to develop increased static-passive flexibility and is much more effective than either passive stretching or active stretching alone. Isometric stretches also help to develop strength in the "tensed" muscles (which helps to develop static-active flexibility), and seems to decrease the amount of pain usually associated with stretching.

The most common ways to provide the needed resistance for an isometric stretch are to apply resistance manually to one's own limbs, to have a partner 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 your foot to keep it from flexing while you are using the muscles of your calf to try and straighten your instep so that the toes are pointed.

An example of using a partner to provide resistance would be having a partner hold your leg up high (and keep it there) while you attempt to force your leg back down to the ground.

An example of using the wall to provide resistance would be the well known "push-the-wall" calf-stretch where you are actively attempting to move the wall (even though you know you can't).

Isometric stretching is not recommended for children and adolescents whose bones are still growing. These people are usually already flexible enough that the strong stretches produced by the isometric contraction have a much higher risk of damaging tendons and connective tissue. Kurz strongly recommends preceding any isometric stretch of a muscle with dynamic strength training for the muscle to be stretched. A full session of isometric stretching makes a lot of demands on the muscles being stretched and should not be performed more than once per day for a given group of muscles (ideally, no more than once every 36 hours).

The proper way to perform an isometric stretch is as follows:

1. Assume the position of a passive stretch for the desired muscle.
2. Next, tense the stretched muscle for 7-15 seconds (resisting against some force that will not move, like the floor or a partner).
3. Finally, relax the muscle for at least 20 seconds.

Some people seem to recommend holding the isometric contraction for longer than 15 seconds, but according to SynerStretch (the videotape), research has shown that this is not necessary. So you might as well make your stretching routine less time consuming.

PNF Stretching

PNF stretching is currently the fastest and most effective way known to increase static-passive flexibility. PNF is an acronym for proprioceptive neuromuscular facilitation. It is not really a type of stretching but is a technique of combining passive stretching (see section Passive Stretching) and isometric stretching (see section Isometric Stretching) in order to achieve maximum static flexibility. Actually, the term PNF stretching is itself a misnomer. PNF was initially developed as a method of rehabilitating stroke victims. PNF refers to any of several post-isometric relaxation stretching techniques in which a muscle group is passively stretched, then contracts isometrically against resistance while in the stretched position, and then is passively stretched again through the resulting increased range of motion. PNF stretching usually employs the use of a partner to provide resistance against the isometric contraction and then later to passively take the joint through its increased range of motion. It may be performed, however, without a partner, although it is usually more effective with a partner's assistance.

Most PNF stretching techniques employ isometric agonist contraction/relaxation where the stretched muscles are contracted isometrically and then relaxed. Some PNF techniques also employ isometric antagonist contraction where the antagonists of the stretched muscles are contracted. In all cases, it is important to note that the stretched muscle should be rested (and relaxed) for at least 20 seconds before performing another PNF technique. The most common PNF stretching techniques are:

the hold-relax

This technique is also called the contract-relax. After assuming an initial passive stretch, the muscle being stretched is isometrically contracted for 7-15 seconds, after which the muscle is briefly relaxed for 2-3 seconds, and then immediately subjected to a passive stretch which stretches the muscle even further than the initial passive stretch. This final passive stretch is held for 10-15 seconds. The muscle is then relaxed for 20 seconds before performing another PNF technique.

the hold-relax-contract

This technique is also called the contract-relax-contract, and the contract-relax-antagonist-contract (or CRAC). It involves performing two isometric contractions: first of the agonists, then, of the antagonists. The first part is similar to the hold-relax where, after assuming an initial passive stretch, the stretched muscle is isometrically contracted for 7-15 seconds. Then the muscle is relaxed while its antagonist immediately performs an isometric contraction that is held for 7-15 seconds. The muscles are then relaxed for 20 seconds before 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 in conjunction with static and isometric stretches. It is very risky, and is successfully used only by the most advanced of athletes and dancers that have managed to achieve a high level of control over their muscle stretch reflex (see section The Stretch Reflex). It is similar to the hold-relax technique except that a dynamic or ballistic stretch is employed in place of the final passive stretch.

Notice that in the hold-relax-contract, there is no final passive stretch. It is replaced by the antagonist-contraction which, via reciprocal inhibition (see section Reciprocal Inhibition), serves to relax and further stretch the muscle that was subjected to the initial passive stretch. Because there is no final passive stretch, this PNF technique is considered one of the safest PNF techniques to perform (it is less likely to result in torn muscle tissue). Some people like to make the technique even more intense by adding the final passive stretch after the second isometric contraction. Although this can result in greater flexibility gains, it also increases the likelihood of injury.

Even more risky are dynamic and ballistic PNF stretching techniques like the hold-relax-swing, and the hold-relax-bounce. If you are not a professional athlete or dancer, you probably have no business attempting either of these techniques (the likelihood of injury is just too great). Even professionals should not attempt these techniques without the guidance of a professional coach or training advisor. These two techniques have the greatest potential for rapid flexibility gains, but only when performed by people who have a sufficiently high level of control of the stretch reflex in the muscles that are being stretched.

Like isometric stretching (see section Isometric Stretching), PNF stretching is also not recommended for children and people whose bones are still growing (for the same reasons. Also like isometric stretching, PNF stretching helps strengthen the muscles that are contracted and therefore is good for increasing active flexibility as well as passive flexibility. Furthermore, as with isometric stretching, PNF stretching is very strenuous and should be performed for a given muscle group no more than once per day (ideally, no more than once per 36 hour period).

The initial recommended procedure for PNF stretching is to perform the desired PNF technique 3-5 times for a given muscle group (resting 20 seconds between each repetition). However, HFLTA cites a 1987 study whose results suggest that performing 3-5 repetitions of a PNF technique for a given muscle group is not necessarily any more effective than performing the technique only once. As a result, in order to decrease the amount of time taken up by your stretching routine (without decreasing its effectiveness), HFLTA recommends performing only one PNF technique per muscle group stretched in a given stretching session.

THOSE ABOVE ARE COLLECTED FROM SOME BOOKS AND WEBSITES..

THANK YOU,

SRIKUMARAN PHYSIOTHERAPY CLINIC & FITNESS CENTER