Great article from Runner’s World on whether we should stretch before running. The choice is yours but this will make you understand the difference. Reminder: it doesn’t question warming up! Enjoy and please share.
“It’s pretty well established that static stretching (the kind where you hold a position at the edge of your range of motion for, say, 15 to 60 seconds, as opposed to bouncing around in “dynamic” stretches) has a dampening effect on strength and power. That’s most likely due to changes in neuromuscular signaling or perhaps at the level of the muscle fibers themselves, and is most relevant for sprinters and team-sports players. For distance runners, there’s also some evidence, but more conflicting, that static stretching may temporarily hurt your running economy – in other words, you burn more energy to run at the same pace after stretching. At least one study has found the same effect in cycling.
The new study took 11 recreational runners and had them run a series of lab tests and 3-km time trials (all on different days) with and without stretching beforehand. The stretching protocol involved seven lower-body stretches, each performed three times and held for 30 seconds, taking a total of about 20 minutes. Here’s what the resulting speed looked like throughout the time trial:
The filled squares are the non-stretching trials, and the open squares are the stretching trials. There’s a significant difference after the first100 meters: the runners started more slowly after stretching [UPDATE 6/19: I erroneously wrote “800 meters” when I first posted this blog entry – the difference in speed was only significant after 100, but the difference in perceived exertion (below) was significant for 800 meters]. Their overall finishing times didn’t end up being significantly different.
So were the runners just trying harder at the beginning of the non-stretching trials? Actually, it was the opposite. Here’s the perceived exertions during the time trials:
So after stretching, the runners started out running slower but felt like they were working harder compared to when they didn’t stretch. Other tests showed that their drop-jump height (a measure of explosive power) was also lower after stretching, but they didn’t find any difference in running economy. The authors conclude that static stretching results in “a reduced capacity of the skeletal muscle to produce explosive force” that translates into a slower starting speed during the race.
Now, as noted above, the overall finishing times for stretching and non-stretching didn’t end up being significantly different. It could be that stretching forced the runners into a slower start, but once the effects wore off (seemingly after a few minutes) they were able to compensate by speeding up and finishing in the same time. Or it could be that the study was too small to pick up any differences in finishing time. For me, the bottom line is that I can’t see anything good about something that makes me go slower but feel like I’m trying harder. So if RW runs another debate on stretching before running, you can guess which side I’ll be on.”