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The Final Word on Stretching and Exercise

Does stretching prevent injury? Does it weaken muscles?


In grade school, it was simple: stretch the hamstrings for 10 to 15 seconds, followed by the quads and calves and a set of sloppy jumping jacks, then you’re off. Now, with scientific studies on stretching making contradicting headlines every year — one year stretching reduces workout injuries and improves performance, the next year the opposite is true — prepping the muscles seems as mystifying to fitness rags as sex moves are to Cosmo.

Like most things (including the preferred subject matter of Cosmo), stretching is simpler than it’s been construed. Much of the prevailing confusion, says Kyle Stull, Senior Master Trainer at TriggerPoint Performance Therapy and Master Instructor at the National Academy of Sports Medicine, stems from uncomprehensive research. “In the laboratory we’ll typically take one muscle then we’ll measure its strength — this is common with quadriceps. They will strap somebody into a machine, they will measure the strength of the quadriceps, then they will stretch the quadriceps out.” After a static stretch, wherein the muscle is held at a point of tension for 30 to 45 seconds, the strength of the quadricep is retested. “Of course, the strength of the quadriceps will go down after that static stretch; that’s where the research comes up, ‘well static stretching is bad.’

“If somebody moves perfectly they don’t need to be stretching anything anyway; but in my almost 13 years of being in the industry, I’ve never seen anybody that moves perfectly.”

Unfortunately, taking such an isolated view skews the truth about how the body works. “If we were to test that person’s jump height [after stretching the quadriceps]”, says Stull, “the strength of the quadriceps went down, but then they have increased the strength their glutes or their rear end. So maybe with their jump, their performance actually increases.” Moreover, there are too many factors to conclusively prove that stretching prevents pre-workout injury; what we should be emphasizing, Stull says, is proper form.

“If somebody moves perfectly they don’t need to be stretching anything anyway. But in my almost 13 years of being in the industry, I’ve never seen anybody that moves perfectly”, he says. Perfection in form is the thing to aim for. Stretching, rather than being your sole safeguard against injury, is what makes it easier for your body to approach perfect form. Likewise, tightness isn’t a necessary precursor to injury. It is an indicator that you should stretch more, if that tightness is impairing your workout. But the solution isn’t to just static stretch that muscle to hell.

To Stull, the most important question to ask is: why are you stretching what you’re stretching? It’s not only about what muscles, joints and tendons are used in your workout, but how those pieces are moving and working. This should inform your stretching routine, which, whether you’re a runner, a biker or a bodybuilder, should be a balanced mix of static, active and dynamic stretches, each of which performs its own important task.

Each stretch performs its own important task.

Static stretching, as described before, involves holding an isolated muscle taut for, typically, 30 to 45 seconds. “It’s typically the most looked down upon”, says Stull, “but it can also be the most effective.” Static stretching works to compensate for certain conditions that are unnatural to the body, alleviating tension they might cause. For example, “if [a runner or a cyclist] is wearing a heeled shoe throughout the day, there’s a really good chance that we’re going to need to stretch their calves. Anything that puts that ankle in a less than ideal position — static stretching has been proven to be very effective in adding length back to the calves.”

Active stretching or active isolated stretching is the moving of a joint through a single motion, to be held at the apex of that motion. This prepares the joints (more so than the muscles) for the movement that the coming exercise will entail — the proper execution of which is, to reiterate, of utmost importance in preventing injury. So a runner, to continue that example, would want to carry out active stretches on the knees, hip flexors and thoracic spine (upper back). Same goes for bikers.

Dynamic stretching carries the muscles through motions that mimic the coming exercise, using momentum to ease muscle tension, allowing those muscles to adjust to those motions so that they can be carried out properly and efficiently. For a runner, this would be a walking toe touch (for hamstrings) or a walking lunge (for quads); for a weight lifter, this would mean a body weight squat.

Across the variety of exercise methods and athletic practices, Stull sees the ankles, hips and thoracic spine as constants that must always be stretched, with the major difference being the pattern of movement you’re preparing them for. And of equal importance to all of this is the oft-misunderstood warmup. “People think of a warm up as hopping on a treadmill for five or 10 minutes”, says Stull. “And you’ll start to sweat, but you really don’t change the body temperature very often.” More important than body temperature is the movement of blood to the necessary tissues; while body temperature is an indication of this, it is too often overemphasized. Ever the advocate for the foam roller, Stull recommends using the tool before your pre-workout stretch to specifically warm up the necessary muscles and joints. Further, MIT suggests slow joint rotations and simple calisthenics such as jumping rope; targeted warmups — e.g., leg raises for a runner — are another good option.

In short: When you know what your body needs for the exercise you’ve come to call your favorite, then all you need to worry about is following directions. Feels a bit like you’re back in grade school, doesn’t it?

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