Then, on four different days, each athlete warmed up at a human performance lab.

Their warm-ups were lengthy. In some past studies of stretching, volunteers had stretched but not otherwise warmed up. In the real world of sports, though, warm-ups 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 warm-ups.

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 warm-up.

At the end of each warm-up, 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 warm-up. 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 was no difference in performance on each day,” says Tony Blazevich, a professor with the Center for Exercise and Sports Science Research at Edith Cowan University in Joondalup, Australia, who led the study.