Once, stretching before team sports and other activities was almost ubiquitous, especially so-called static stretching, during which you assume a pose and hold it for anywhere from a few seconds to several long minutes.
But static stretching has fallen out of favor in recent years, after studies showed that prolonged static stretching might cause reactions in the nervous system that temporarily weaken the stretched muscle. Consequently, athletes would not spring quite as high or sprint quite as fast after lengthy bouts of static stretching.
So, many coaches and organizations, including the American College of Sports Medicine, began to advise against static stretches and advocate instead for dynamic stretching, during which limbs and joints stay in motion.
During a static stretch of your quadriceps muscles, for example, you might stand up, grasp one foot, ease it up until your heel touches your backside and stay in that position.
A dynamic version of that same stretch would entail tugging your foot a bit farther up your back, then releasing your foot to the floor, and repeating the motion multiple times. It was thought that such dynamic stretching should bypass any negative impacts on performance, while helping muscles and joints to warm up and prepare for intense activity.
But little research has examined the actual performance effects of dynamic stretching.
So for the new study, which was published in June in Medicine & Science in Sports & Exercise, a group of international scientists, many of whom work with elite, national-team athletes, decided to test different stretching routines.
They began by recruiting 20 young, male athletes who play team sports like soccer or rugby that involve running, sprinting and sudden shifts in direction — activities that are believed to demand a thorough warmup.
To control for placebo effects, the researchers asked the athletes what kind of stretching, if any, they each expected would aid their performance. Almost all named dynamic stretching.
Then, on four different days, each athlete warmed up at a human performance lab.
Their warmups were lengthy. In some past studies of stretching, volunteers had stretched but not otherwise warmed up. In the real world of sports, though, warmups tend to be elaborate.
To better emulate those conditions, the athletes in this study began with a few minutes ...of easy jogging, followed by stretching, and then an additional 15 minutes of increasingly intense sprinting, jumping, zigzagging and other moves.
During the four days of the experiment, only the stretching changed during these warmups.
In one session, the athletes completed nine very brief static stretches of various muscles, with each stretch lasting five seconds.
On another day, the same nine static stretches were held for a total of 30 seconds each.
On a third day, the same stretches were all done dynamically.
And on a fourth day, the athletes did not stretch during their warmup.
At the end of each warmup, the athletes completed a battery of tests of their flexibility, jumping, sprinting and agility.
Then the researchers compared their numbers.
Surprisingly, they found that the men’s performances had not changed, no matter what their warmup. They were just as swift, agile, powerful and lithe when they had not stretched as when they had, and whether that stretching had been static or dynamic.
There also was no placebo effect; although the men almost universally had expected dynamic stretching to prepare them best for the coming activities, it had not.
These results have multiple implications, Blazevich continued.
They suggest, for one thing, that stretching does not bolster athletic performance when it is part of a full warmup. But at the same time, they show that stretching does not impede performance, Blazevich said, even when the stretching is static.
In practical terms, these findings suggest that if you enjoy and trust stretching before a competition or workout, you may as well keep stretching, Blazevich said.
“Our subjects felt more prepared for the tasks when the stretching was included,” he said.
On the other hand, people who hate to stretch before exercise could probably skip the effort, he said, if they otherwise warm up.
Of course, this was a short-term study and included only fit young men who play team sports. Whether the findings apply equally to older people, women and those of us who participate in activities like distance running or cycling is still up in the air.
“We need to test all of that in the future,” Blazevich said. “More to do!”
The New York Times