Flexibility is depicted both in the media and in the fitness industry as a key factor in joint and muscle health. The current train of thought appears to be, “The more flexible you are, the less likely you are to injure yourself.” The recent popularity of yoga in the United States bolsters this perspective. It is difficult to walk down the street without seeing someone toting a yoga mat.

Yoga, if practiced correctly and within the constraints of one's ability, has the potential to be a useful tool in maintaining health. Many yoga poses have functional relevance. For example, the cobra position facilitates extension of the lower back, a position that is often lost from sitting on an office chair for eight hours daily. The tree pose addresses strength and balance within one's center of gravity.

Many people derive positive mental and physical benefits from yoga who would have otherwise been sedentary. The focus of this article however deals with how to correctly attain IDEAL flexibility.

The reality of yoga is somewhat different from its public persona. The simple truth is many practitioners of yoga either have have, or develop through the practice of yoga, too much flexibility. Excessive flexibility can result in stretched out joints and muscles that do not function optimally.

A common injury to see with practitioners of yoga is chronic lower back pain. Upon examining these individuals, abnormal amounts of flexibility both in the hips and in the joints of the vertebral segments of the lower back is seen. These people often have pelvises that are “unstable”, and translate too much from side to side with gait.

While lying on the examination table, a hyper-mobile person is able to bring his or her leg well above ninety degrees while keeping the knee straight. This is a sign of muscles that are in a chronically lengthened position. All of this can arise from performing an activity that is heralded as slow, kind, and gentle.

The dangers of over stretching are two-fold. The first danger is that muscles that are too long, or over stretched, can not provide adequate support to the surrounding joints. Over stretched muscles under-perform when asked by the brain to contract through a full range of motion. This phenomenon is typically the result of maintaining a stretched position for long periods of time. This phenomena has been identified and labeled “over stretch weakness” in physical therapist Shirley A Sahrmann's book, Diagnosis and Treatment of Movement Impairment Syndromes.

A common example of chronically stretched muscles involve the abductors of the hip. Women, who have broader pelvises than do men, are in danger of stretching out their hip abductor muscles from sleeping on their sides. Picture a woman side-lying on a bed: with the placement of her knee from the top leg on the bed, a stretch is placed on the outer part of the “top hip” (the hip not in contact with the bed). The long and slow stretches that are often seen in yoga are analogous to sleeping with a muscle in a stretched position. Although yoga stretches are not typically imposed for as much time, the intensity of the stretch is far greater.

A chronically over-stretched muscle in many cases barely has an overlapping of the parallel fibers. The result can be an inhibited ability of the cellular bands to move over one another: a diminished quality of contraction is observed.

One of the functions of healthy muscle is to absorb the stress that we place on our bodies through walking, sitting, and performing other functional activities. An elongated and weakened muscle has a diminished capacity to absorb stress: the result is increased stress on the joints of the body. This is why a “sachet” style of walking that is often seen in hyper-flexible people, with the pelvis moving excessively from side to side, can be harmful to joint health. The joints of the lower back and the pelvis are constantly in a state of over-use as they are not receiving the “cushioned” effect that normal muscle bought to be providing.

Individuals who have muscles that are chronically overstretched are seldom aware of it. Many people actually develop neuroses about stretching. They stretch every time they get a chance and feel that it is a necessary part of their fitness routine, even if they are encountering pain. Newcomers to yoga witness the flexibility of their classmates and instructors and immediately feel inadequate. As with any group activity, a sense of competition with fellow students may also develop. There is also the basic psychological need to please your teacher. All of these factors contribute to the larger picture of muscles that are in a chronically lengthened state.

It is also worth mentioning that many people are born with an excess amount of joint and muscle flexibility. There are many people who can, while standing, touch the palms of both hands to the floor without any prior stretching or practice. These people in short do not need to pursue stretching as a form of exercise: they would be much better off working on core strengthening through activities such as Pilates. Women are more likely than men to fall into this category.

A second danger arising from excessive spending involves the muscles, but the ligamentous structures that support the joints. Clinically speaking, this is a more serious problem for the reason that joint structures respond to over-stretching differently than muscles do. Muscles that are too long can be retrained to work at a more ideal length. Exercises to shorten lengthened muscles will be demonstrated later in this article in detail.

The ligaments and cartilage that protect joints are likened to the plastic that surrounds a six pack of beer: once you have stretched out that plastic by pulling a can out of the six pack, there is no turning back. The plastic will forever remain in the stretched out position, just as the joint and the ligament develop permanent length changes.

As an example, let us use the hip joint in relation to stretching of the hip flexor muscles. As many of you know, the hip flexors are the muscles located in the front portion of the upper thigh, some of which originates on the lower spine and front of the pelvis. These muscles allow us to lift our leg and help to stabilize various various bodily positions.

For most individuals with ideal muscle health, when the leg is lowered to the horizontal position to the table (in a 2 joint hip flexor stretch, I could not download the photo !!!), a light stretching sensation may be felt in the front portion of the hip and thigh. In this position, the muscles in the front of the hip encounter a stretch. This limit in the muscle length blocks the hip from further extension.

Now consider what would happen if you focused a great amount of time and energy on stretching out your hip flexors to the point where you could lower your knee considering below the horizontal position of a 2 joint hip flexor test.

If the leg is brought down far enough, the ligaments that support the front portion of the hip joint are now placed under a stretch. Many people often misinterpret this ligament and joint capsule stretching as muscle stretching, and, therefore, consider it a good thing. Nothing could be further from the truth. Over time, we are left with muscles that are too long to support the joints correctly and joints that have been unreparably stretched out.

My initial instruction to patients that I see with this “over-stretched” phenomena is simple: Stop stretching. In most cases, a cessation of stretching will greatly reduce their lower back pain within a few weeks.

Most people when confronted with this information inevitably begin to question the merits of stretching as a means of improving their health. Have we been lied to by the countless trainers, therapists, instructors, and media about the virtues of stretching? There is, after all, widespread clinical data that supports the positive effects of stretching. In my clinical setting I, admittedly, stretch people every day.

How do we know what in fact is the appropriate amount to stretch?

The key to answering this question lies in the knowledge of normal muscle and joint ranges. If you have an excess range in a certain position, there is no inherent benefit in continuing to stretch into that position. An exception to this rule would involve people that need excessive range of motion for some job or activity. Dancers, acrobats, and other professional athletes may require considering more than the normal range of flexibility to perform selected activities.

On the other end of the spectrum are individuals who lack normal muscle flexibility. I routinely see people who could not lean forward to touch their toes if their lives depended on it, myself included. This is the population that would in fact benefit from a bit of muscle stretching. I have treated many of these “stiff” patients who have, in fact, benefited from joining a yoga class. It may even be possible that a tight muscle group may be contributing to an imbalance in your body that is causing pain.

The overall message here should be quite clear: it is a good idea to gently stretch muscle groups that lack normative range, and it is a bad idea to stretch muscles that already have more than normal range. If you have muscles that meet the normal ranges, then stretching needs only to be used as a “warm-up”, or for the purpose of maintenance. Your goal should not be surpass normal ranges of muscle flexibility.

Muscles that are too long actually need to be re-trained to work in a more normal range. This is why it is key to be able to readily identify exactly which muscle groups in your body are in need of stretching, and which muscle groups are in need of re-training.