How Flexible Should Runners Really Be?
Flexibility – as an aspect of overall fitness – is a pretty interesting and controversial topic. Of course, experts agree that it is important. But, like so many things in the health and fitness world, balance is needed. Runners have traditionally been taught that they should be flexible enough to lean forward and place their palms flat on the ground. Unfortunately, most runners can’t pull off this particular feat of flexibility. So, what’s the problem? Is this really an issue? How flexible should runners really be?
Running and Flexibility
To fully understand this question, it’s important to first explore the relationship that exists between running and flexibility. And, to be clear, this relationship is two-sided.
First, as you run and progress in your training, certain muscles and tendons in your legs do naturally tighten. Specifically, a runners calves tend to be fairly rigid. Traditionally, this has been seen as a bad thing. But more on the modern scientific understanding later.
For now, let’s consider the opposite side of the equation – how your flexibility impacts your running. Try to imagine the form and function of your lower leg as you run. When you step down, your feet, ankles, calves and knees all soften to absorb the impact, compressing like a giant, complicated spring. During the forward motion, though, that stored up potential energy is released to move your bodyweight.
There is a complex interaction, then, between your training as a runner and the flexibility of your legs. While it is obvious and well-documented that running decreases your flexibility, though, it’s the other side of things that tends to be so hotly debated. How does flexibility affect your athletic performance?
Historically, the primary reason for coaches and athletes to emphasize flexibility training was based on the idea that it can prevent injuries. Which, logically, makes a lot of sense. After all, the more flexible you are, the better prepared your joints will be to handle any unexpected changes to your running surface which – in turn – could help you avoid falls and strains.
But this is theory. Does this concept actually work in the real world?
Unfortunately, no. It doesn’t seem that way. One particularly telling piece of research analyzed the results of 361 different studies and papers on the subject, all in an effort of understanding whether or not flexibility has anything to do with injury rates. And, in all that data, the team found no relationship. Flexibility did not have any statistically significant impact on a runner’s risk of suffering from an injury.
So the injury thing has been largely debunked, despite the efforts of a few hold-outs who refuse to let their stretching routine go. But what about the idea that increased flexibility can enhance your athletic performance?
In large part, this is based on the spring illustration discussed earlier. The more flexible and responsive the spring of your muscles and tendons is, the more efficiently they will be able to handle your weight. Or, at least, that’s how the theory goes.
The research, however, doesn’t necessarily agree. One study from Cal Poly compared the running economy of 21 male runners with their ability to touch their toes. Interesting, the less flexible men were statistically better runners. Which is opposite the standard understanding.
Looking at this, the tendency might be to jump in the other direction and conclude that it’s actually better to be stiffer. Which is pretty great news for everyone out their who hates stretching. Science, sadly, is rarely that straightforward.
Further research has found that stiff tendons around the knees increasing running performance while stiff plantar flexors actually decreases performance. The issue of running efficiency and flexibility, then, isn’t just a simple matter of whether or not it’s better to be more flexible. It all really comes down to which tendons and muscles you’re talking about.
What It All Means
With all of this seemingly contradictory and convoluted research in your head now, what should you do with it? How does all of this help you understand how flexible you should be as a runner?
The studies discussed above highlight two key points. First, flexibility – generally speaking – doesn’t improve your athletic performance or reduce your risk of injury. Second, we have to remember that your legs and feet are incredibly complex machines with lots of moving parts. While increase flexibility in one area might be a good thing, other regions could benefit from being more ridged. Researchers are still sorting all that out.
The big takeaway, then, is this: If you are running pain-free, don’t worry about your level of flexibility. Of course, you could develop limiting pain or stiffness in your legs during the course of your training. This is a signal to slow down and do some stretching. In this case, flexibility training could do you good.
- The Impact of Stretching on Sports Injury Risk: A Systematic Review of the Literature, Journal ,
- Relationship between elastic properties of tendon structures and performance in long distance runners., Journal ,
- Passive and active muscle stiffness in plantar flexors of long distance runners., Journal ,