A lot of people really enjoy stretching, I’m not really one of them. I always see scores of people doing some sort of stretching before a race. Yoga seems to be more popular than ever. I remember distinctly the flexibility tests we had to do as a young boy in my elementary school’s physical education class. I hated them.
My attempts at gaining some degree of lower body flexibility while training in Judo, JuJutsu, and Karate was largely a failure. My long legs and incredibly inflexible joints made groin and split stretching practically impossible to do on my own. My instructors weren’t deterred though, and the impromptu torture sessions instigated on a semi-nightly basis certainly provided a degree of amusement for the dojo.
I also tried to apply prehab stretching as a way to keep myself from getting injured while running or doing Crossfit workouts. That was largely unsuccessful, as injuries kept me from running or doing Crossfit workouts for at least three months out of one particular year.
So, as anybody who is faced with a seemingly insurmountable obstacle is likely to do, I decided to research whether or not I should even bother trying to become more flexible in the first place. I really wanted to know if there was a benefit to all of the discomfort and frustration.
Would increasing my flexibility provide a tangible benefit to my athletic pursuits, and would stretching techniques facilitate this effect?
Here is what I’ve managed to determine so far:
Stretching before or after exercise doesn’t provide a clear protection against injury. There may be some anecdotal or personal accounts which suggest otherwise, but meta-analyses  of pertinent research into the matter have not provided any conclusive corroborating evidence for this. This is important because injury-reduction is one of the most common reasons I hear people say that they work at flexibility.
On the other hand, running with proper form and minimalist shoes (or barefoot) is probably going to do more (than stretching) to keep you from busting up your knees like I did. Also, approaching high intensity workouts with weights without an attitude of “must ignore pain and finish at all costs” is more conducive to injury prevention.
Stretching before or after exercise doesn’t provide a significant reduction in soreness. This is probably the next big reason people stretch after injury-prevention. Another meta-analysis  of stretching for this focused area has come up with a similar conclusion – it doesn’t really help. If there was a benefit, it was infinitesimally small. If delayed onset muscle soreness is caused by micro-tears in the muscle tissue, I don’t really see how stretching the muscle further would help the situation.
After thinking about this some more, it seems to me that the most effective way to avoid post-exercise muscle soreness is to not exercise with sufficient intensity such that you induce microtrauma in your body’s muscles. Every time I push my limits a little, the next day or so I feel some soreness. If you overload your body, it will have to repair the damage. If stretching has worked for you in this regard, I’m honestly thrilled for you and a little jealous. But, generally speaking, it doesn’t seem to pan out.
Being more flexible can potentially reduce your endurance running capabilities. A concept that is important for anybody trying to generate power with their legs is muscle tension. The energy transferring abilities of tendons and the torque generating capacity of muscles are key to your body’s ability to turn biochemical potential energy into biomechanical kinetic energy out on the track. Apparently, the less flexible your lower body is, the more economical you are when it comes to endurance .
This was a study employing that infamous sit and reach test which I hated so much as a child. I suppose having super flexible legs is beneficial for all kinds of things. I’m not trying to suggest at all that flexibility is inherently bad. But in the case of distance running, it doesn’t seem to be that beneficial.
Static stretching before a run or workout can further reduce your capabilities. Some different experiments have looked at the effect of static stretching before endurance activities like running  and explosive power generating activities like squat jumps . In both scenarios, there was a measurable decrease in work output in those subjects which employed static stretching before the assigned exercises.
Again, this seem to be a case where pre-workout static stretching has decreased the mechanical efficiency of the muscle system, possibly due to a reduction in tendon stiffness, or some other related mechanism. I kind of imagine the whole thing like stretching out a rubber band so much that it doesn’t spring back to its original size. If our tendons are naturally engineered to act like rubber bands, then stretching them out before using them is counter-intuitive.
Ok, so what if flexibility is important to you and you still want to incorporate that into your training?
Like I said before, despite my distaste for stretching exercises, I recognize the importance of flexibility for many different vocations, sports, and hobbies. And, some people simply enjoy stretching, like doing yoga and stuff of that nature. What is one to do?
Apparently, doing dynamic-stretching movements before your workout is less likely to incur any kind of reduction to your performance . The idea is to use functional movements that stimulate blood flow to the muscles, while keeping them moving through their full range of motion. For runners, this will include exercises like heel kicks and high knees.
If enhanced flexibility is important to you, and a potential for reduction in running economy isn’t, then just try to incorporate your deep stretching routines or yoga sessions on days in between your normal workouts. Or do your stretches after you’ve already worked out and are doing a cool down session.
Ultimately, I hope the take away from this article is not that I’m trying to vilify stretching and end it’s practice completely. I just think the practice of stretching needs to be examined and utilized more objectively, and maybe we can sacrifice a few sacred cows as well while doing so.
If you want to get some more information on stretching and the muscles/soft tissue involved, you should check out the book Stretching Anatomy. It has a lot of great illustrations and tips if you’re interested in revamping your stretching routine.