Is Stretching Harming You or Helping You?

Today I’m writing about the conflicting and often heated world of stretching.

After over a decade of studying, reading, and writing about the research on stretching, I have witnessed an enormous range of data and corresponding interpretations. I’ve seen studies that say stretching makes you weak and slow and I’ve seen studies that say stretching makes you strong and energy efficient. I’ve seen studies promoting stretching as an essential component of fitness and other studies arguing it should be eliminated altogether.

This span of conclusions is even greater in the court of public opinion. 🙄

As someone who receives a steady stream of messages from yoga teachers ranging from “Is stretching dangerous?” to “Will stretching heal me?” I understand how confusing and overwhelming the topic can be. I also understand that to navigate the complexity, it helps if you:

• are well-versed in the entire body of stretching literature.
• have a comprehensive background education in major areas of exercise science (e.g. tissue mechanics, physiology, rehab).
• embrace nonlinear and non-binary thinking.

Luckily for you, these are 3 attributes I proudly own. 🙋🏼‍♀️ Let me expand on each.

The Research on Stretching and Flexibility Exercises

As you probably know, I lead an evidence-based webinar on stretching twice per year. This webinar changes slightly each time I present it because, in the 6 months between each iteration, dozens of new stretching papers get published. I comb through them regularly and choose to highlight some of the more impactful studies (i.e. good-quality papers by well-established research teams that contribute to the field).

One that I’ll be including in the upcoming iteration is this 2024 paper by Warneke, titled Revisiting the stretch-induced force deficit: A systematic review with multilevel meta-analysis of acute effects. Here is a statement from the conclusion: “Since no effects could be found for athletic performance, our results do not support previous recommendations to exclude static stretching from warm-up routines prior to, for example, jumping or sprinting.“

Why is this important? There are a lot of people out there with very strong opinions about performance deficits caused by stretching. To be fair, the research was pointing that way back in the early 2010s. But it’s now 2024 and we know more. Yet I still come across a lot of people (including athletic coaches and academics) who hold on to this position tightly.

Recently, when a colleague of mine was sent an aggressive and arrogant message about her stretching practices having a detrimental effect on athletes, she was struggling to defend herself. She ended up attending my webinar and this was the feedback she sent me: “Your work is heads above everyone else. I encounter and think about how to respond to the anti-stretch narrative that is out there. Your webinar clarified some things for me and gave me concrete rebuttals to it. Thank you 🙏😍”

It’s my goal to help you think about stretching in a more complete, nuanced, and contextual manner.

In order to achieve that, you’ll want the whole story: what has been studied, what is being studied now, and what still needs to be studied. The webinar includes approximately 100 slides and I provide links to dozens of original studies so you can further your own studies on the topics that interest you most. There is no reason you should doubt your knowledge of stretching again!

The Background Education in Anatomy and Biomechanics for Yoga Teachers

Part of thinking about stretching in a more complete, nuanced, and contextual manner requires a solid background education in connective tissue mechanics, muscle physiology, pain science, research methodology, and more.

I recently got a comment on Instagram that suggested that pressing the heels down in Downward Facing Dog Pose was leading to “overstretched” Achilles tendons. While I appreciate exercising caution, understanding the mechanical properties of tendons would go a long way in realizing this might be an unnecessary concern.

Tendons undergo far more strain (length) and stress (load) during other activities like running, jumping, and weight lifting than during a yoga stretch (and we have studies that have measured this). The webinar, consequently, includes an overview of connective tissue mechanics.

Naturally, I received a new email question just last week from someone with an Achilles tendinopathy asking about which type of stretches will improve his flexibility the most (assuming that improving flexibility would alleviate the heel pain). This is literally the exact opposite message of the one above where stretching caused Achilles tendon problems – in this case, it was supposed to solve Achilles tendon problems. I see why everyone is so confused!

Here, I think understanding that flexibility is not always a peripheral tissue issue is a good place to start. Learning a bit about muscle physiology and how muscles behave when stretched (versus connective tissue) would help. It’s important to understand that being “tight” is primarily a feeling and that most of what limits range of motion is your ability to tolerate the sensations associated with stretching. These are all topics I expand upon in the 3-hour webinar.

The Nonlinear & Non-Binary Thinking: An Essential Practice for Yoga Teachers

One of the biggest traps you can fall into is thinking about stretching in a linear or binary fashion. Stretching does not follow a step-by-step straight path where A leads to B which leads to C and so on, nor does it follow a black-and-white or yes/no pattern. Biology is always nonlinear and multifactorial.

First of all, not all stretching techniques are the same, nor do they have the same outcomes, target tissues, or mechanisms of action. Understanding the 6 types of stretching helps you think contextually. Second, different people (and different muscle groups) respond differently to the same intervention. Recognizing this can help you appreciate why similar studies can yield conflicting results. Lastly, even when A does sometimes lead to B, we have to assume a multitude of things we did not or cannot measure occurred along the way, and we have to accept that A will not always lead to B.

For example, did you know you can do stretching exercises and feel better, but you don’t need to improve ROM? Or that you can do strengthening exercises and get out pain, but you don’t need to actually need get stronger? Or that you can do corrective exercises intended to improve faulty kinematics and your symptoms can improve without changing your kinematics? People with or without pain can be flexible or tight, strong or weak, and have “good” form or “bad” form.

Once you embrace all this uncertainty, each paper you read and each piece of evidence you gather just gets added to your vault of uncertainty™. The more you know, the more you know you don’t know. This makes you a more confident yoga teacher as you realize how much you already know and a more compassionate yoga teacher as you realize how much you don’t know you don’t know. Did you follow all of that? 😆

It is my goal to show you an intellectually fearless path where you are comfortable in uncertainty and crave endless curiosity.

Here is some recent post-webinar feedback that summarizes my teaching ethos: “Your combination of kind, compassionate, curious and science-based education is invaluable in our community.“