For years, women were told to take long-term post-menopausal hormone replacement drugs, that is until someone did a study on the topic with 16,000 women over a long term. Much to everyone’s surprise, the hormone replacement drugs were found to increase heart attacks, strokes and breast cancer. It’s amazing what happens to a commonly held belief when someone actually studies it! The same can be said for stretching before running. We were all told to stretch before running based on what? When the subject is actually studied, we find through an abundance of research that stretching before running not only doesn’t help reduce injury, (some say it may increase injury) but stretching actually hurts performance. I read about this frequently, yet just when I think the idea of pre-run stretching is dead, I see a group of runners stretching like mad before they run. I feel like Michael Douglas sitting on the edge of the bathtub: I thought Glenn Close was dead at the bottom of the bathtub, but then she sits bolt upright with a knife in her hand – yikes, she’s back!
Hopefully (at least for the people who read it) this post will be Michael Douglas’ wife shooting pre-run stretching in the heart.
In the interest of not getting boring, I will try to not break down every study, but give a one or two sentence summary with a link to each research paper. Try to remember that we are talking about “static” stretching here (i.e. stretch and hold), not dynamic stretching like leg swings, hip circles, scorpions etc. There is actually research supporting dynamic warm ups before running. We’ll cover proper pre-run dynamic warm-up routine in an upcoming newsletter. OK, on to the research:
- There are quite a few studies trying to figure out whether or not stretching reduces injuries in sports. Lucky for us, there are other researchers who examine all of these other individual studies and step back to come up with a consensus statement about what all the other individual studies have said. These review studies all conclude that static stretching before sports generally does not reduce injury (2002 study, 2003 study and 2004 study)
- More specific to running, the USATF recruited 3000 runners to either stretch or not stretch before running for a period of 3 months. In the end, there were no differences in injury rates (16% on both sides). (2010 study here)
The evidence that pre-run static stretching reduces performance is much more clear. I haven’t taken the time to list most studies. Generally, these studies are performed by analyzing the “running economy” of the subject runner. Running Economy is usually calculated by measuring the amount of oxygen consumed by the runner at a given pace (think fuel economy in a car).
- Runners who did static stretching before endurance running (65% VO2max run) had worse performance than those who didn’t stretch before the run (full text 2010 study)
- Runners who stretched before running had worse 20m sprint performance (2005 study)
- Runners who were less flexible had better running economy (2009 study)
- Stretching before cycling also reduces cycling efficiency and time to exhaustion (2011 study here)
- Another cycling study showing stretching before cycling hurts performance (September 2011 study here)
Why is the running economy worse after stretching? Well, the researchers think that it’s due to the stored elastic energy and stiffness in a muscle. In other words, when we run, there are certain phases of the gait cycle where certain muscles undergo a stretch, then recoil mechanism. If you reduce the stiffness in the muscle/tendon, then there is less recoil. Less elastic recoil means more work needs to be done by actually contracting the muscle. Hence, more work.
I know this post may be touching a “flat earth” nerve with some people. I’d love to hear feedback. Just reply to the email – don’t boil my family’s pet rabbit.