[podcast]https://edwardwillett.com/wp-content/upLoads//2009/07/Stretching.mp3[/podcast]
There’s a perception that science is always reversing itself. If you don’t like what science has to say about, say, the health benefits or risks of a particular food (eggs, for example, or coffee), you only have to wait awhile until a contradictory study comes out.
That’s because science progresses in fits and starts. Researchers put forward a possible explanation, a hypothesis, for the results of an experiment. Other researchers attempt to duplicate their results and refine the hypothesis. Sometimes the hypothesis is completely discarded, and a new hypothesis gains sway.
But in the media, this slow process is seldom reported. It’s much easier to pick up on the report of a single study—particularly if it has startling results—and present the hypotheses put forward by its authors as fact, rather than simply one possible interpretation.
I’m sure I’ve been guilty of that myself in this column, though I try to avoid it by using phrases which, if I could only charge a dollar to every reader for each use, would have long since made me rich: “One possible explanation…” “The researchers suggest…” and, of course, “More research is needed.”
By this time you’ve probably twigged to the fact that I’m about to tell you that something you may think is a fact is anything but—and you’re right.
Go to any gym, and you’re likely to see people engaging in the time-honored practice of static stretching, bending themselves into a pose that pulls muscles and tendons tight and holding it for a few seconds.
They do this because they’ve been told, at some point, that it’s important to “stretch out” before engaging in vigorous physical activity, in order to avoid injury.
Guess what? In all likelihood, they’re wasting their time.
This isn’t exactly news, or shouldn’t be. As Cynthia Billhartz Gregorian points out in a story in the St. Louis Post-Dispatch, it’s been five years since the Centers for Disease Control and Prevention reviewed 361 research studies done by its epidemiology program office and found no evidence that stretching either before or after exercise prevents either injury or muscle soreness.
In fact, some sports medicine experts say static stretching actually inhibits performance, decreasing power and speed, and can cause micro-tears in tendons, ligaments and muscles. Nor is stretching going to help you work out a strain: stretching it makes it worse, not better. Strained muscles should be rested, and then the focus should be on rebuilding strength.
So should you give up stretching altogether? (You know, just like you gave up coffee and chocolate before you found out both are good for you?)
No; but you might want to think twice about static stretching. Modern thinking—you know, as opposed to that old pre-2004 thinking—holds that dynamic stretching is the way to go: moving through stretches without pausing or holding a position, walking forward while grabbing the knee toward the chest, that kind of thing. A little jogging in place or skipping while swinging your arms, or going through the required motions of a particular sport at half-speed might help.
Now, static stretching does have some benefits. If you do it every day for three months, it will make you more flexible, for instance. “Senior athletes” can benefit by doing traditional stretching after—but not before!–their main workout, because it helps minimize the effects of arthritis and joint degeneration. And any athlete can benefit from static stretching after prolonged exercise because it reduces lactic acid accumulation in heavily exercised muscles.
But beforehand? Not recommended.
When you think about it, our physically active ancestors didn’t worry about stretching. As California doctor-and-author Dr. William Meller points out, “Can you imagine a caveman engaging in a program of stretching before heading out to chase down prey?” And I doubt most farm hands carefully stretched before going out for a day of tossing hay bales onto a wagon.
So why have we been stretching all these years? Because at some point, researchers decided it was good for us. Scientists continued to study the issue, however, and our knowledge evolved.
Which gives me great hope, because personally, I’m hoping for a study that says the whole “exercise is good for you” thing is similarly misguided.
If I find one, you’ll hear it here first!
3 comments
You are so right! This idea about the purported effects of a sugary diet began more than 80 years ago with a case report in the American Journal of Diseases in Children.It has only grown from there. I also have never found any science to back it up. The Straight Dope covered it very well about a year ago.
http://www.straightdope.com/columns/read/2747/does-giving-sweets-to-kids-produce-a-sugar-rush
I have also looked in the idea that milk products are “mucus forming” and traced them to a single quack doc in Southern California back in the second decade of the last Century! It is amazing how these things grow and spread.
Bill
Dr. Meller, thanks for dropping by. I suspect you’re right about where the stretching meme came from originally (and that did cross my mind when I was writing this…but it’s a hard thing to confirm one way or the other).
The other “what everybody knows isn’t necessarily right” thing I’m always trying to convince people of is that there’s no scientific evidence that eating sugar makes kids “hyper.” That one’s more entrenched than any of them, I think!
Dear Edward,
This post is great coverage of an important topic. I appreciate the mention of my recent book at the end. You will find a lot more counter conventional ideas like this in Evolution Rx.
I couldnt agree with you more about the process and progress of science. It is more the finding of truth by eliminating all the alternatives.
In one respect though I dont think we can blame the stretching myth on researchers. I think it came out of the sports and “wellness” community and then was adopted by physical therapists, a not very research based area of medical practice. It seemed to make sense so it took a long time for researchers to get around to questioning and testing it. A lot like the specious recommendations to drink 8 glasses of water a day and to use ice and/or heat when we have a sprain.
Keep up the great writing and spreading the word.
Dr William Meller