Why Do We Stretch?
For most, stretching is something that comes with the territory. If you’re about to lift, you get a stretch in, and off you go. You’ve always done it. But why do we stretch? Surely, it’s not because “well, everyone’s doing it”?
Maybe, as part of your sign up, your gym offered personal trainer “evaluation” and they told you to stretch. Even better, your workout partner bestowed their wisdom on you and urged you to stretch your hamstrings before squatting.
But you’re past the taking advice, you want to know for yourself. You’ve become serious about exercising and want to take it to the next level.
So as you’re going over your workout regimen, your nutrition, and your recovery, and you realize that you’ve been stretching for years, but you don’t know why. Better yet, you don’t even know if you’re doing it right.
Maybe you can squat more with proper stretches? Or maybe they’re good for nothing?
Luckily for you, we’ve gone through the science. The results are … surprising.
There’s more to stretching than the quick routine that most follow. Specifically, you can break it down into two categories; static and dynamic.
While both methods are distinct, their benefits aren’t far off from each other. Supposedly, they both increase your range of motion, prevent injury, and increase flexibility.
Hence, the distinction is in how they achieve the purported benefits.
So, here’s a breakdown of these two types. Our explanation addresses the differences, the pros, the cons, and ultimately answers; why do we stretch?
Static stretching is the most basic stretch. It’s the one size fits all approach. This stretch is the least challenging and most do it as an afterthought.
But with all that comfort, how much benefit can static stretching possibly confer?
Fortunately, several studies have examined static stretching and the supposed benefits.
A Journal of Strength and Conditioning Research published study1 examined whether there was any link between pre-workout static stretching and peak torque performance.
The study authors used a calibrated dynamometer to measure the difference in power output between a subjects’ stretched and un-stretched legs.
Surprisingly, not only did the study find no benefit from static stretching, it actually noted a detriment.
Specifically, the article concluded that “overall, these findings, in conjunction with previous studies, indicated that static stretching impairs maximal force production. “
A further study2, in The Physician and Sportsmedicine Journal, cited “misconceptions and conflicting research reports” when making stretching recommendations.
Even after pouring over the available data, the article recommended a paltry “one 15 to 30 second static stretch per day as sufficient for most patients.”
After, the authors recommended an individualized approach “if one is even necessary.”
Let’s be clear, it’s not because static stretching is so effective that 15 seconds will remedy all your problems. Instead, the researchers simply don’t see much wisdom in the static stretching one size fits all approach.
In our minds, stretching served many purposes; increased flexibility, reduced soreness, injury prevention, and optimal performance.
Naturally, when a Clinical Journal of Sports Medicine article3 disputed the link between soreness and stretching, it caught our attention.
The study conducted two separate experiments examining stretching as it relates to delayed-onset muscle soreness (DOMS). Hence, the data was unique in that it reflected two separate studies. It also examined effects from stretching before and after eccentric exercise.
But in both cases, the results were the same, stretching showed no reduction in DOMS.
A 2002 paper4 analyzed two previous studies linking stretching and injury prevention.
The two studies “evaluated the effects of stretching before exercising on the risk of injury in new military recruits undergoing 12 weeks of initial training.”
Both sets of data yielded similar risk reduction estimates. Specifically, the analysis found that “exercising does not seem to confer a practically useful reduction in the risk of injury.”
Of the two underlying studies, the first subjected participants to supervised muscle stretches, while the second “investigated effects of stretching six muscle groups in the lower limbs before and risk of soft tissue, bone, and other injuries.”
Needless to say, the data was thorough.
So if static stretching isn’t effective, are there alternatives?
Dynamic stretching is the more involved alternative. This method is more challenging, but still relatively comfortable.
Unlike static stretching, dynamic stretch requires more coordination and is performed in sets with reps. It’s more of an exercise itself, and less of a warm-up routine.
But are these added benefits any more conducive to better performance and injury prevention?
A 2008 study5 examined the short-term effects of warm-up, static, and dynamic stretching on hamstring flexibility. The study was significant for several reasons.
First, it included several pre-workout regiments; warm-up, static stretching, and dynamic stretching. In this sense, it was more encompassing than others.
This was particularly salient as it allowed researchers to examine effects of different pre-workout regiments, and didn’t confine them to one particular mode.
Second, the study’s multi-faceted examination evinced a clear distinction between the three methods. Specifically, “warm-up significantly increased hamstring flexibility. Static stretching also increased hamstring flexibility, whereas dynamic did not.”
While the findings reflect favorably on static stretching as it related to flexibility, don’t assume that increased flexibility translates to injury prevention or reduced soreness.
A 2013 article6 examining whether “we have enough evidence on stretching during warm-up” shed further light on the connection – or lack thereof – between flexibility and injury prevention.
The authors noted that “research on stretching demonstrates a five to twenty percent increase in flexibility within four to six weeks of stretching.” However, this increased flexibility does not translate to injury prevention.
One possible reason for the broken link is that “increased joint mobility may come at a cost of decreased joint stability.” In fact, this instability may account for “higher injury rate of athletes in the highest 20 percent flexibility distribution.”
To sum it up, increased flexibility may be causing joint instability, which in turn increases injury likelihood.
More Harm than Good
A 2013 study7 examining dynamic stretching as it affects performance overall, put it in the same camp as its static counterpart.
Initially, the authors noted that “research documenting the performance benefits of stretching is limited.” They went on to conclude that “support for the notion that performance can be enhanced if stretching is undertaken just prior to an event is lacking.”
No performance advantage, no reduced soreness, and injury is just as likely. So again, why do we stretch?
Dynamic v. Static
It’s not all doom and gloom, however, a 2008 study8 comparing effects of static versus dynamic stretching highlighted one particular difference.
The study’s results suggested that “overall, an acute bout of dynamic stretching may be less detrimental to muscle strength than static stretching.”
Unfortunately, even when dynamic stretching appears to be better, it’s only comparatively so.
Yoga and Stretching
Maybe the benefits aren’t all there like we thought. But keep in mind, we’re looking for different kind of “benefits.” Specifically, we’re looking at stretching as it relates to injury prevention and better physical performance.
But it would be short-sighted to overlook the myriad of other benefits. For example, yoga’s physical and mental benefits are well documented. But the data trove advocating for the ancient stretching discipline is not nearly as important as the anecdotal evidence.
Both athletes and regular folks alike cite yoga and ‘regular’ static stretching as a conduit to greater life qualify. So if stretching is working for you in the way you desire, that’s all that matters.
Our objective was to look at the relationship between stretching and injury prevention and better physical performance.
We found that static and dynamic stretching do increase flexibility, but those gains don’t translate to injury prevention or optimal performance.
So why do we stretch? Because there’s a life outside the gym.
Because for millennia people experienced different benefits from stretching and to an extent yoga.
Whether it’s physical; through greater flexibility and better posture, or spiritual; through better breathing, mood control, and optimistic outlooks, if it works for you, then you know exactly why you’re stretching.