Well, according to an article published over at Runner's World, apparently not! To be honest, I don't really want to link to the article because I think it is kind of bull, but if I am going to write about it then I better link to it. You can also get the actual study being examined here.
Ok, let's break this down. I really think this author took these research results and took them completely out of context.
First, they end up mostly agreeing with a body of previous research suggesting that increased range of motion following a prolonged stretching program is mainly the result of increased tolerance to the sensation of stretching, rather than actually loosening the muscle-tendon unit. That is, you get better at pushing a little farther when you're at the extreme edge of your range of motion.
Our muscles have a defence mechanism called the Golgi Tendon Organ which senses changes in muscle length. If your muscle is lengthening too fast or too far then you have a reflexive action that essentially locks things up and won't let you go any further. It takes a long time (per session as well as number of stretch sessions) to be able to relax your body enough to get past this defence mechanism. This is why we hold stretches for a while or use things like PNF stretching, using a contract-relax cycle to help inhibit this reflex.
This study was done for 3 weeks.
Let that sink in for a second....I stretch all the time and I witness almost no measurable changes in my flexibility in 3 weeks either. It takes months and years of consistent effort to get and maintain flexibility. Just as someone who gets up off the couch and starts training for a 5km run, you are not going to see immediate changes in your range of motion or flexibility.
Not only that, but this study was conducted on the calves. Off the top of my head I'm quite certain the ankles have the least amount of range of motion out of all of the body's joints. I guess it was an easy selection because the ankle really only bends in one direction (minor inversion/eversion).
Static stretching helps improve circulation, aides in recovery, but most of all, it is intended to increase range of motion.
I just got back from a USA Weightlifting course over the weekend in Rochester. One of the key contributing factors for weightlifters (can be applicable to other sports too) is the fact that flexibility and full joint range of motion is not only critical to success, but strongly promoted for safe training. Weightlifters are some of the most flexible athletes in the world!
Having said all of that, static stretching should not be done prior to a workout. It has been proven to not reduce risk of injury and can even decrease strength and power performance. However, stretching at the end of workouts when the body is still warm is still highly recommended to increase range of motion to properly perform exercises safely and effectively.
To be honest, this is an interesting topic of research/discussion. How important is flexibility? I don't believe everyone needs to have the flexibility and range of motion as say a gymnast, however an increase range of motion for the average population would probably benefit those at risk for injuries.
Take back injuries, for example. I would love to see a study conducted on improving flexibility of things like the lower back, hamstrings, hip flexors, abdominals, gluteals, etc. (common low back pain causers) over a long-term study (longer than 3 weeks) in order to see the benefits of flexibility training.