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Stretching the Truth: Why Do People Stretch?

Thomas L. Teter Jr. DC

Recently there have been many gym members asking various questions about stretching, its use, and forms of application. Stretching is a topic that is often confusing, polarizing, or that offers an incomplete message. There are a lot of things about stretching we know, but there are also a lot of things we are not completely sure about. Since this is a very vast and complicated subject, In order to do it justice we must break down the many facets of stretching in order to gain a complete picture of its use in a fitness setting. Because of this, I will be writing a five part series on the subject, starting with one of the more important topics of conversation regarding the issue - Part one : Why do people stretch?

When challenged, many stretching enthusiasts have a hard time explaining why they are stretching. Everyone just “knows” that it is a good thing, but they haven’t really thought about why. When pressed for reasons, most people can cough up a few predictable goals of stretching. The most common reasons people give for stretching include:

            1. Warming up

            2. Prevention of injury

            3. Prevention of muscle soreness

            4. Increasing flexibility

            5. Improving performance

Some of these overlapping stretching goals have serious problems. Either they have been long ago been proven to be impossible, or they lack sensible rationale. There is a multitude of research on this particular topic that shows that stretching for any of the aforementioned reason is a waste of time. Stretching may be beneficial for other reasons, which we will get to later, but for these goals, there may be better options.

The research on stretching shows that it is not an effective warmup. Nothing about stretching has been more clear. A 2011 review of the research on stretching showed that stretch durations of 30 to 45 seconds imparted no significant effect on muscle tissue, and even some evidence of harm. One of the main goals of a warmup should be to increase tissue temperature, as we know that warm muscles perform better than cold ones. However, body heat is generated by metabolic activity, especially muscle contractions. It is impossible to raise your metabolic activity without working up a sweat, which cannot be done with static type stretching. The concept of warming up could refer to readiness for activity, or being neurologically responsive and coordinated. Many research studies have shown that stretching actually delays muscular contraction times and decreases intramuscular coordination. Because of these findings, stretching does not qualify as an appropriate measure for preparing for activity.

According to the evidence, stretching probably does not prevent injury either. In 2005, the Clinical Journal of Sports Medicine published a review of the studies to date, that found that the evidence showed stretching had no effect on reducing injury rates. It actually showed that injury rates for all kinds of injuries were the same, with or without the use of stretching. Stretching made no difference whatsoever.

Another popular idea about stretching is that it prevents deep muscle soreness following a hard workout. This soreness is referred to as delayed onset muscle soreness. Current studies strongly suggests that stretching is completely useless for preventing soreness. In fact, there have been a few studies that have suggested that stretching can actually prolong the soreness of exercise, as by attempting to elongate muscle fibers that have been damaged due to exercise creates a low level of inflammation.

Another reason people justify the use of stretching is to become more flexible, or to increase range of motion. The real question that needs to be asked in this regard, is do you need to be more flexible. Most people have relatively normal amounts of joint range of motion, so unless you are frustrated with a specific lack of joint range of motion, you probably do not need to be more flexible. The truth of the situation is the only way you can deform a muscle in an attempt to make it longer, is to apply large amounts of force of at least 65% of the muscle’s tensile strength, for a minimum of 30 to 45 minutes. This means that if you are truly trying to change the length of a muscle, you have to hold a really hard stretch for at least 30 minutes of a static position. Anything other than this is not actually changing muscle length, assuming that we actually can, and at best is causing damage to the passive connective tissues such as the tendon or ligaments surrounding the joint. Prolonged use can actually create long term damage such as tendonopathy, and ligamentous laxity that can lead to joint instability.

The last major argument you get for stretching is that stretching can improve your physical performance. Some suggest that it might make you faster, or even be able to produce more power. Research has shown that stretching does not improve your sprinting times or power output, but actually it makes it worse. In one study average power output dropped by 30% following a routine of static stretching of 45 seconds. There are obviously many mitigating factors in the use and effectiveness of static stretching, but it is clear that it is not very useful for performance improvements.

As you can see, this topic can be very complicated as there is not one correct answer regarding the effectiveness for the different reasons that people stretch. The evidence is very clear that as a general statement stretching is not the most effective intervention for the goals that we stated above. In fact, stretching can in some instances have detrimental effects. This information is presented to you to outline the facts of stretching, so as a fitness enthusiast you can make the best informed decision on whether its use is right for you and your goals.

Next time in part two, we will discuss the different types of stretching and the ways each type is used in fitness and sport.

If you have any specific questions, please feel free to contact me at my office, and in the mean time, use this as some food for thought to help you move well.