The Science of Stretching: Part I

Happy New Year! I started this blog back in June, and did not post as much as I intended, but am happy that I managed to keep it up at all. The intention with the blog was to offset some of the more academic research I am doing in school, and share some of my musings on (loosely) health-related topics. For this coming year, I am hoping to do more frequent shorter posts. With that in mind, stay tuned for PART TWO of this blog later in the week. 

The science of pain and injury seems to be similar to the science of nutrition: no one really knows what is good for you. Eggs used to be the enemy, now they are healthy. Fats used to be poo-pooed, now people are going paleo and caveman. (And let’s not even get started on coconut oil!) The same confusion surrounds pain and injury: do we ice an injury or not? How much rest is beneficial for pain versus detrimental? And the big one currently is…. STRETCHING! There is a whole industry built around stretching (certain types of yoga, particularly Yin Yoga), and stretches are often included in programs given by physiotherapists, massage therapists, and other bodywork practitioners. We tend to think the most flexible student looks the best in a yoga class and often strive to seriously stretch our hamstrings so we can look just like the yoga models (props to Musicians' Health Collective for a great recent post on hypermobility.) BUT - researchers and movement therapists are trying to get the word out that stretching might not actually be all that great for you! Wait, what?… what about all those recommendations from health care practitioners? And what about the fact that stretching just feels so good?

First, let’s stop for a minute to consider why pain is such a complicated area. Pain messages come from the brain, so pain does not always equal damage. Someone with tissue damage can feel virtually no pain, while someone with chronic pain can have no visible damage. It doesn’t mean one type of pain is more valid than the other, but just reinforces the complexity of it all. The function of pain is to warn us of something dangerous happening, so we can (theoretically) then avoid the danger (an aside: the stuff out there on the relationship of pain to emotion, mental states, and trauma is just incredible!) To show the immense complexity of pain, just think about this: surgeons can perform intricate surgery at the drop of a hat, yet no one has figured out a “cure” for chronic low back pain (I use low back pain (LBP) as an example here because LBP is often quoted as an epidemic: it is estimated that 80% of the American adult population will experience LBP at some point in their lives, and treatment expenses are growing each year).

Now back to stretching. Stretching is very popular, but there are many myths surrounding stretching. Jules Mitchell is an expert in this area: she is a certified in yoga training, massage therapy, and a number of other movement therapies, but she is unique in that she also has a Masters of Science degree in exercise science/biomechanics, and her Masters Thesis was on the science of stretching. About a year into her thesis work she discovered that what she learned from the yoga community was not supported by science. The myth in the yoga community is that if you stretch more and harder, the muscle you are stretching will get longer, increase range, and increase flexibility. The science says this is not true and is just damaging tissue; she illustrates this by saying that if you hold a rubber band and stretch it, once you release it (thereby releasing the load) it will go back to its original shape. We have the idea that if something hurts, we should stretch it. But alternatively, someone in pain should leave it alone and instead move frequently in full ranges of motion and gradually increase the load.

The science of stretching seems to say: Stretching is not an effective warm up. Stretching does not prevent injury. Stretching, especially long held stretches, can cause injury. Stretching probably doesn’t improve athletic performance.  

So then why does it feel so good, and why do we often have the “urge” to stretch? As Greg Leman of Pain Science explains, lots of things feel good without have any clear physiological benefit. There might very well be actual benefits (aside from feeling good) to stretching, but it seems that no one knows them yet. Also, it might not just be about the stretching but what you are doing while you are stretching. If you are in a yoga class, you might be getting benefits from the breathing, meditation, and flow at the same time as the stretching.