Add this to the list of things your gym teachers got wrong: how and when to stretch. Since grade school, you’ve been told to warm up by lengthening a muscle until it begins to sting, then holding that position for 30 seconds. This technique, known as static stretching, was also intended to ward off injuries. But before you follow that rule again, consider this: Multiple studies attest that stretching is important but needs to be practiced differently in order to be protective and performance enhancing. For instance, a 2010 review published in the Scandinavian Journal of Medicine & Science in Sports found that doing static stretching before exercise may have no impact on your odds of getting hurt and could actually impair your ability to run faster or hit a tennis ball harder.
Here’s why: “Normal slow stretching suppresses the motor neurons that control muscle reactions,” says study author Malachy McHugh, PhD, director of research for the Nicholas Institute of Sports Medicine and Athletic Trauma in New York City. As a result, the straining muscles become less responsive—that is, weaker—afterward. “In essence, you’ve spent a few minutes telling your muscles to stretch out and relax, then two seconds later ask them to perform at speed, which they can’t do right away,” says Meghan Kennihan, certified personal trainer and USA Track & Field coach with Well-Fit Triathlon & Training in Chicago.
What’s a more effective warm-up? Research points to dynamic stretching, which loosens muscles via continuous movements, like the kicks and arm swings that often open an aerobics class. Static stretching, if done after exercise rather than before, can also be beneficial, helping you enhance overall flexibility and—bonus!—age more slowly. Here’s what you need to know about both of these body boosters.
Best Prep: Dynamic Stretching
“With this technique, you move your muscles through the motions you expect them to perform during exercise,” says McHugh. Spend five to 10 minutes doing activity-specific movements, such as jumping vertically before a soccer game or doing trunk rotations in anticipation of a tennis match. Steadily ramp up the speed and amplitude of the movements (for instance, by jumping faster and higher). This prepares the neuromuscular system for action by slowly activating an increasing number of muscle fibers and raising your heart rate, body temperature and blood flow. “Instead of getting an inhibitory response, as you would with static stretching, your muscles get a message to perform, because you’re firing them in the same way you intend to use them,” McHugh explains.
Researchers don’t know if repeated dynamic stretching improves flexibility over time, but a number of studies show that it boosts performance more than static stretching or no stretching at all before exercise. In studies, golfers who first did dynamic stretches struck golf balls with more speed, soccer players improved their 20-meter sprint times, and exercisers performed leg extensions more powerfully.
Kicking off exercise with dynamic stretching may also prevent injury, by warming up the muscles, says Julie Gilchrist, MD, a researcher with the Centers for Disease Control and Prevention. In her study, female soccer players who did a warm-up that included dynamic stretching three times a week suffered 41 percent fewer knee injuries than their peers in a control group. For a basic routine that will prepare you for walking, jogging or nearly any other cardio exercise, visit more.com/dynamicstretches.
Best for Everyday Flexibility
While a static stretching routine isn’t the best warm-up for an exercise session, it does provide powerful anti-aging benefits—especially if you’re sedentary (hello, desk job) most of the day.