Stretching Before Exercise or Running: Why You Should Stop It, According to Research

I have vivid memories of sitting in a circle with teammates as The Coach cycles us through our stretches before practice/gym.

“Ok, legs together and down. Touch your toes, and keep those knees straight! Now hold.”

I never wondered why we stretched, or if it actually worked. I just assumed that Coach knows best, and I made up reasons why it’s probably good for the muscle fibers and being “limber,” and the… tendons or something.

Well it turns out Coach was wrong, and we were all doing a dumb thing for no reason.

That’s right, as hard as it is to believe, generations of coaches have been teaching an ineffective warm-up routine (between deep hits of doctor-recommended Camel no-filters and leaded gasoline fumes).

Sports medicine has come a long way since we were 15, and we now have a scientific understanding of how, why and when to stretch. So we have no excuse anymore!

If you’ve always wondered what the research actually says about stretching, read on.

How does stretching affect performance?

Current Sports Medicine Reports found in 2014 that:

“Static stretching by itself immediately before strength and power activities diminishes performance […] When performed prior to speed and agility activity, static stretching is detrimental to performance… it is notable that no study shows a performance benefit from static stretching performed prior to [endurance] activities.”

The Effects of Stretching on Performance, PubMed

But there is good news: they found the opposite results for dynamic stretching, also known as “warming up to end-range.” To paraphrase their findings: dynamic stretching improves performance for strength and power, and speed and agility activities when performed immediately prior to the event.

While there is not enough data to say whether it also improves endurance performance, it was not found to be detrimental, and further research is ongoing.

Static stretching might not improve performance, but doesn’t it prevent injury? Isn’t that the reason we all engaged in the sacred circular “stretching ritual” in high school?

Does Static Stretching Prevent Injury?

The short answer is: nope.

A study published in the British Journal of Sports Medicine found stretching had no effect on preventing injury, while strength training had the greatest, statistically significant effect for reducing risk of injury.

When you break down what static stretching does to the muscle, this isn’t surprising. Stretching deactivates the muscle, reduces blood flow, and creates small tears in the fibers. These should all be red flags before exercise. 

McHugh (2009) reports

“There is an abundance of literature demonstrating that a single bout of stretching acutely impairs muscle strength, with a lesser effect on power”

McHugh is also quoted in Stretching: The Truth “there is a neuromuscular inhibitory response [created by] static stretching.” 

Translated into plain English, he is saying that static stretching makes your muscles less responsive to signals from your brain. It “inhibits,” or reduces, the connection between your nervous system and the muscles you want to use when running. Not good!

I recommend a warmup routine that activates and increases blood flow to muscles. My warmup routine is included in my ShamelessPlug.info running program.

So… Why Stretch At All?

This might be the most important question, and the answer depends on your goals. Your answer could be as simple as, “It feels good, and I have the time.” Now that we have more information on when to stretch to not increase risk of injury, and how to be effective in your stretching, go and enjoy. 

The article Can chronic stretching change the muscle-tendon mechanical properties? Reports that static, dynamic, or PNF (fancy static stretching with a partner) for 8 weeks had no perceptible effect on the properties of the tissue being stretched. It only seemed to alter our perception by increasing tolerance to a greater extension and applied force. Increased tolerance and a change in perception are a big deal, but it’s important to know that it appears to be all in our heads.

On the other hand, if you don’t have the range of motion needed to perform your sport, or certain tasks that are important to you, you should do strength training, and dynamic stretching to increase your tolerance to a greater range of motion. You should do the same if you find a mobility imbalance that is affecting your running form.

We all have imbalances in our bodies, but dynamic stretching might not be the solution. I will help you diagnose and fix form issues you may be unaware of in my RunningProgram.cool.

How Should I Stretch?

In short: active or dynamic stretching works, passive and static stretching doesn’t.

Passive, static stretching is what we are familiar with. Holding a stretch for 20-30 seconds while most of the body is relaxed. 

Dynamic stretching means that we flex the opposing muscle group to the end of our range of motion briefly, but not hold it at end-range. For example, activating the quad and hip flexor to straighten your leg, and feel a brief stretch of the hamstring. This is actually more like warming up muscle groups to their end range of motion, not what we consider stretching.

Should I Feel Guilty About Not Stretching?

If you don’t care about ‘mobility’ or that good stretch feeling, then don’t worry about it.

If your goal is to increase strength and endurance, you are happy with your current range of motion, or you think that stretching can replace resistance training or other forms of exercise, don’t stretch. It’s a waste of your time and energy. 

So spread the word and help end the myth that stretching before exercise prevents injury or improves performance.

Just don’t tell Coach. I don’t want him to yell at me. 

This article contributed by Evan Turner

Sources

1 Peck E, Chomko G, Gaz DV, Farrell AM. The effects of stretching on performance. Curr Sports Med Rep. 2014 May-Jun;13(3):179-85. doi: 10.1249/JSR.0000000000000052. PMID: 24819010.

2 Lauersen JB, Bertelsen DM, Andersen LB. The effectiveness of exercise interventions to prevent sports injuries: a systematic review and meta-analysis of randomised controlled trials. Br J Sports Med. 2014 Jun;48(11):871-7. doi: 10.1136/bjsports-2013-092538. Epub 2013 Oct 7. PMID: 24100287.

3 McHugh MP, Cosgrave CH. To stretch or not to stretch: the role of stretching in injury prevention and performance. Scand J Med Sci Sports. 2010 Apr;20(2):169-81. doi: 10.1111/j.1600-0838.2009.01058.x. Epub 2009 Dec 18. PMID: 20030776.

4 Reynolds, Gretchen Stretching: The Truth. The New York Times. 2008 Oct 31 

5 Freitas SR, Mendes B, Le Sant G, Andrade RJ, Nordez A, Milanovic Z. Can chronic stretching change the muscle-tendon mechanical properties? A review. Scand J Med Sci Sports. 2018 Mar;28(3):794-806. doi: 10.1111/sms.12957. Epub 2017 Oct 9. PMID: 28801950.