the effects of (in)flexibility

By Ian Nurse, DC

“I’ve been stretching my hamstrings all the time, but it doesn’t seem to help. I still can’t come close to touching my toes and it seems to make my hamstring feel worse!”

This is a statement that I hear from runners on a weekly basis in my practice. It’s not a big surprise considering that we have been instructed to stretch since the beginning of our athletic careers. I still have images of my youth soccer coach yelling at us at the start of practice, “Go take a lap and then circle up to stretch!”

Stretching and running have always gone hand in hand as the cure for sore, overused muscles and the “must do” in order to stay injury free. That’s why I tend to get a lot of blank stares when I tell these same running patients, “You should stop stretching.” It’s as if I have told them Santa doesn’t actually exist.

Over the last few years, as we have learned more and more about our bodies and running economy, the role of flexibility and stretching in terms of long distance running has become unclear. To stretch or not to stretch has become quite the controversy in the sports and rehab arena. Some sources say stretching is good, but only at certain times. Others say never stretch. Is dynamic stretching better than static? When should one stretch? Some say never before you exercise, only after. With so many differing opinions, many runners are completely overwhelmed. Unfortunately, this article may not give you a definitive answer you are looking for. We are all experi-ments of one, and what works for someone may not work for others. Hopefully what this article will do is shed some light on the current research and give you some alternatives to stretching.

Most recently, Matt Fitzgerald, a leader in the running/sports science world, wrote an article relating to a specific gene that is linked to both inflexibility and running economy. The Cliffs Notes version of his article is that scientists have found a specific gene that accounts for how flexible muscle tissue is. If you have this certain gene, COL5A1, not only is it less likely you’ll be able to touch your toes, but you are also MORE likely to beat all those people who don’t have it at your favorite 5K. Yup, inflexibility and speed actually go hand in hand. Fitzgerald states, “Muscle fibers are like rubber bands. Some are tight and others are loose. The loose ones stretch more, but they can’t store and discharge a lot of force. The tight ones can’t stretch very well but they can store and discharge a lot of force.” As runners we need tight muscles to help store and release the energy needed to propel us forward.

Unfortunately, not all of us have this gene. However, not all is lost if you are not the proud owner of COL5A1. As many of you have probably noticed, the more you run, the less flexible you become. This is your body’s way of adapting to your training. Just as our lungs expand, our muscles learn to store more glycogen and our bones become denser with training, our muscle fibers are also adapting by becoming less flexible in order to become more economical. While we used to think of this as a negative side effect of running that we must try to combat through excess stretching, we are slowly realizing that it is actually a benefit to our running.

Now here comes the tricky distinction that needs to be made: inflexibility and immobile joints are not the virtue of runners but rather the muscle fiber elasticity associated with the inflexible muscles. It’s important for run-ning economy to have normal ranges of motion in your joints, especially your hips. So how do you keep your joints mobile and maintain that elasticity? One possible solution is to ditch the excess stretching and increase the foam rolling and mobility exercises.

The key to healthy tissue and mobile joints is twofold: blood flow and movement. Our muscles need blood and movement in order to heal. After vigorous exercise they crave that blood and all the nutrients and oxygen that come along with it in order to replenish what has been lost and to restore normal tissue. As much as we have be-come accustomed to sitting on the living room floor strug-gling to hold the same stretches we learned when we were 6 years old, 15-20 minutes of both foam rolling and mobility exercises are a great alternative to keeping your body healthy and limber but not losing your muscle elasticity. I recommend foam rolling of all the major lower leg muscles, glutes and low back at least 4 times a week in order to improve blood flow throughout the tissue and to workout any specific patches of scar tissue that inevitably form during our sport of choice. In addition, performing hip mobility exercises such as the Myrtle Routine 3-4 times a week after a run will help maintain the necessary range of motion that we need for proper form and that is so easily lost due to our tendency to sit all day during our jobs.

I don’t know about you but I haven’t been able to touch my toes since the 1990’s, in fact, I’m lucky if I can get half-way down my shins. Apparently, despite what my youth soccer coach told me, that’s not all that bad of a thing but rather a sign of my body adapting to my training and trying to make me as efficient of a runner as possible. In-stead of trying to fight that inflexibility with stretching, embrace it but also make sure you are being proactive in maintaining your mobility and giving your body what it needs to heal.

Dr. Ian Nurse is The Level’s resident body expert. This article originally appeared in the Jan/Feb 2014 issue of Level Renner. Get your free subscription today (box in upper right portion of screen).