Flexibility: More is not necessarily better.


Juan Carlos Santana, MEd, CSCS

If you ask coaches or trainers why their athletes or clients should stretch you will get a myriad of different answers. You will hear that it increases range of motion (ROM), prevents injuries, it prepares the body for work, it creates balance between opposing muscle groups, it relaxes you and its fun! Well I suppose that all of these reasons are true to some degree. However, they are not all true, to all individuals, at all times. The reasons to stretch and increase flexibility are individual as your clients.

I have seen stretching nightmares in every gym I have ever been in, trainers doing the same stretches with all of their clients – some right out a torture handbook. The worst and most common offender is the “client on his/her back, knees to the chest, back rounded, butt off the floor, and the 200 lb trainer pushing down on the legs – asking for submission” stretch. Many times it resembles more a pinning combination from professional wrestling than a stretch. Even within the scientific literature, I have rarely seen a real practical and organized approach taken when it concerns flexibility. It is a simple case of “everyone knows that flexibility is good – so more must be better”.

One of the problems with delineating protocols and recommendations is the ambiguous use of terminology. Many times, stretching and flexibility are used interchangeably. The assessments used are also many times inappropriate and do not provide accurate information about specific muscles. Therefore, it would be prudent to start by drawing a distinction between flexibility and stretching.

Stretching is the practice of elongating soft tissue. Flexibility can be defined as “the range of motion possible around a specific joint or a series of articulations”. This definition implies that the body, or joint in question, is at rest while the range of motion is being measured or expressed. This is why it is also termed “static flexibility”. However, motion is an important factor when it comes to flexibility. The consideration of motion into the flexibility equation allows us to draw a distinction between “static” and “dynamic flexibility”.

Dynamic flexibility is the most “functional” (i.e. flexibility you can use). Outside of certain sports, such as gymnastics, flexibility is expressed dynamically and fluidly. Dynamic flexibility also requires control over the entire range of motion at any given movement. This control comes only through a perfect blend of mobility and stability (i.e. functional flexibility and strength). Gary Gray and Vern Gambetta call this blend “mostability”. Gary defines mostability as the “ability to functionally take advantage of just the right amount of motion, at just the right joint, in just the right plane, in just the right direction, at just the right time”.

Practicing stretching will certainly improve flexibility. However, just because you stretch does not mean your are “functionally flexible”. I, along with many of my colleagues, have trained with many elite athletes who practiced stretching regularly and only acquired moderate flexibility levels. Flexibility is very individualized and it is influenced by several factors. These factors include joint structure, tissue mass, age, gender, activity level, training protocol and motion. Joint structure will greatly dictate the flexibility of a joint.

High levels of flexibility have been typically associated with improved athletic performance and reduced incidences of injury. However, scientific research does not unanimously support this notion. Data from several military studies indicate that the most, and least, flexible recruits displayed higher incidences of injury when compared to recruits with “normal” flexibility. There is also a strong body of sports research that shows no correlation between flexibility and improved performance, or injury prevention. Furthermore, many of the injuries that we regularly attribute to lack of flexibility are actually related to neural inefficiency in stabilizing structures. For example, the work by Hodges, et. al. clearly establishes the relationship between lower back pain and inefficient muscular stabilization of the trunk (e.g. transverse abdominus). Lower back pain is just one of the many symptoms that is regularly attributed to lack of flexibility and nothing else.

Flexibility should be seen like any other aspect of physiology and flexibility training should be addressed as any other training component, individually. Would you demand that your tennis player look and move like a middle-linebacker? NO. Then why would we want to make our tennis player as limber as a gymnast? Flexibility, and its development (i.e. stretching) should be specific to the individual and the activity. Activities that require fast changes of direction (e.g. power-dominated sport and manual labor) require stable and firm joints. A hyper-mobile joint, due to “too much” flexibility, is a definite liability in these activities and a sure sight for an injury. However, the same hyper-mobile joint may be seen be an asset in any activity requiring extreme ranges of motions (e.g. gymnastics and dance). “Not all flexibility is created equal.”

Assessing flexibility is another concept we have managed to distort from what is logical and practical. Standard flexibility, and corresponding “norms”, have been developed by the medical and fitness industry. They are used to assess ROM during rehabilitation and screening, and more importantly, provide objective numbers to insurance carriers, patients and clients. For the healthcare industry, this insures payment by the insurance companies. In the fitness industry, it allows trainers to screen clients and track progress. However there is a problem – “these numbers” for the most part don’t mean anything when it comes to functional flexibility. The “sit and reach”, shoulder rotation and trunk rotation tests are all static tests that don’t really correlate to muscle function or performance. These tests do not accurately describe the strength or control of any joint musculature through the range of motion. This is the essence of functional flexibility.

Now, lets talk about flexibility protocols and their particulars. Although I may offer a look at some of the stretching/strengthening exercises I use, I will not offer “one size fits all” protocols. As we alluded to before, stretching and flexibility needs differ from person to person. Therefore, it becomes impossible to offer a single stretching protocol.

Next in line is the big question, why stretch? In my opinion, the primary reason for stretching is to prepare the body for work. A combination of proper warm-up and stretching allows a host of physiological reactions to occur that are conducive to proper function. These processes include:
– Warms up muscle tissues and joint fluids
– Prepares the neurological system for movement
– Increases heart and respiratory rates
– Turns on processes necessary for accelerated energy production
– Psychologically prepares the individual for work

All of these factors may play an important role in injury prevention, improved performance and prolonged athletic careers. However, they are more associated with proper preparation rather than chronically elongating tissue.

There are some instances where the stretching protocol goes beyond preparation for activity. One circumstance would be acquiring an extreme ROM for successful participation in some sport/activity. This situation would obviously be encountered in wrestling, ballet, and gymnastics. Another situation would be to chronically elongate muscles, which in their shortened state negatively effect the proper movement of a structure. This is often found in individuals who perform too much bench pressing. Their shoulders (i.e. shoulder blade) become so protracted (i.e. shoulders rounded), they compromise the function of the external rotators of the arm. This condition would lead to an injury if the individual tried to partake in any overhead activity, especially involving external rotation. A third instance would be to correct a flexibility imbalance between a pair of muscles. This condition exists in one-sided, repetitive sports such as weightlifting, golf and throwing events. In either of these cases a stretching protocol, conducive to chronically elongating specific muscles would be appropriate.

There are four primary categories of traditional stretching exercises. Although a detailed description of each category is not possible, we will provide an abridged description here with some recommendations on their use. The four categories fall under two major groups, active stretching and passive stretching. Active stretching is where an individual’s own muscular force provides the force for the stretch, that is, with no outside assistance. In passive stretching, a partner or outside force provides the force for the stretch.

The most common type of stretching is “static stretching”. It is easy to learn, it’s effective and results in minimal soreness. Static stretching involves complete relaxation while the muscle is elongated. Each stretch is held to the point of minimal discomfort for 10-30 seconds and repeated up to three times. Each stretch should yield a larger ROM than the previous. A slow toe touch, with a 20-second hold is an example of a static stretch. These are the best stretches for a post workout cool down. They are appropriate for all populations. To use them in the warm-up, precede them with 3-5 minutes of light aerobic activity.

The next category of stretching is “dynamic stretching”. This category uses some momentum to create a greater stretch. The stretches are usually functional movements used to prepare for training or competition/activity. The speed of the stretch is kept under control as not to violate safe ranges of motion. This type of stretch is the most popular amongst athletes, especially during the warm-up for explosive, power dominated events. It wakes up the nervous system and really gets the cardiorespiratory system going. Dynamic stretches are not only effective at increasing sport specific ROM, they also serve as biomotor skill training. High knee running is an example of a dynamic stretch for a sprinting athlete.

Ballistic stretching is very explosive, high speed stretching. Although very effective at increasing ROM, it emphasizes the eccentric loading, resulting in a high rate of “delayed onset muscle soreness” (DOMS). It is discouraged for most individuals due to the high risk of the activity. The difference between dynamic and ballistic is one of speed, and more importantly, control over the ROM. Many times the two categories are combined into one, making semantics a cumbersome obstacle when communicating on this subject. The take home message on movement speed and stretching, “is keep it under control and within a safe ROM.
The last category of stretches in “proprioceptive neuromuscular facilitation” (PNF). This type of stretch has about three permutations. It combines a cycle of stretching, contraction and relaxation. Although this stretching method is the most effective at increasing ROM it carries some risk of injury if overdone. The reason for this is that the cycle of contraction and relaxation, of the muscle being stretched, essentially allows us to override the protective receptors we have that safeguard us against over-stretching! PNF is usually partner assisted. It is imperative that the partner be experienced with PNF techniques to keep the risk of injury low. This stretching is best used after the workout, when muscles are very pliable and elastic, to chronically increase ROM.
Now, there is another way to see stretching and flexibility – functional flexibility. I try to incorporate most of my flexibility training in my functional strength program. If a special corrective approach has to be taken, I’ll refer my client to our director of physical a manipulative therapy. I learned from Olympic weightlifters that resistance training can dramatically increase range of motion in the absence of stretching. These athletes are among the most flexible in the Olympics and do very little stretching. However, they train to full ranges of motion. Therefore, I train my clients and athletes to control the ranges they will encounter in their environment. If this means picking up a napkin in a semi-lunge position then that becomes the ROM and stretch I use. If a client who golfs presents a lower cross syndrome and complaints of lower back pain, I may suspect a tight soas. Therefore, I’ll use some golf-related stretch to functionally address this dilemma. Regardless, I personally choose not manually stretched my clients, although I understand they love it and it’s a great “feel good” and marketing technique.

When to stretch, is by far the most agreed upon issue amongst conditioning professionals. Since we have already established that stretching helps prepare the body for work, it is common practice to make it part of every warm up. Since muscle has many of the elastic qualities of rubber, higher temperature increase its pliability and elasticity. Therefore, it is recommended that some light aerobic activity be used to increase muscle temperature prior to stretching in the warm-up session. A post workout (i.e. activity) stretching session may also be included to address the various aspects of structural function targeted for improvement. If you need to elongate the muscle for any reason, this part of the workout offers the best response to the stress of stretching. The increases in muscle temperature and reduced neural inhibition create the optimal environment for prolonged static stretching resulting in chronic muscle tissue elongation.
In conclusion, stretching is an effective method of increasing ROM. Active (no partner) and passive stretching (partner assisted) are two ways to approach a stretching session. Active stretching is the most popular and efficient. The main purpose of stretching is to prepare to body for work, and thus static or dynamic stretching should be part of every warm up. The warm-up, stretching session should proceed a 2-3 minute aerobic warm-up. Stretching can also be used to chronically elongate muscle tissue for specific purposes. For this application, post-workout stretching is the most effective. Passive, static and PNF stretching are the most effective, however, careful attention must be paid to not over-stretch since our protective neural mechanisms are over-ridden. Although the jury is still out on the efficacy of increasing flexibility, assessing it, or developing it, we should re-evaluate our past tendencies to want to turn ALL of our athletes and clients into gymnast or contortionists for the sake of improving their performance or reducing their risk of injury. Most important, remember what my colleague Vern Gambetta says, “stretching has a very specific purpose and its not to win a flexibility contest!”

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