To Stretch or Not to Stretch?

This warm-up activity could be doing you more harm than good.

By Marie Look

Stretching has become a controversial topic in the fitness community due to increasing evidence that stretching prior to exercise is, at best, a waste of time, and at worst, an activity that can decrease muscle strength, lead to injury and lower overall performance. That’s tough to hear, especially since coaches, doctors, educators and parents have reinforced the idea of stretching in many of us since we were kids. But let’s take a look at why everyone is getting bent out of shape, plus what you should (or shouldn’t) be incorporating into your own workout routines.

While stretching can be broken down into any number of differentiating categories, “dynamic stretching” and “static stretching” are two terms that frequently come up. Examples of dynamic stretches would be walking lunges, arm swings and hip circles — all activities intended to warm up the body, accelerate the heart rate and essentially prepare the body for the work ahead. Static stretches, on the other hand, involve holding a certain position for a number of seconds.

Although researchers and health and fitness experts still can’t seem to agree on exactly how effective dynamic stretching is at preventing injury and improving athletic performance, more and more professionals in those fields are convinced that static stretching is ineffective and even unsafe.

In a study at the University of Nevada, Las Vegas, athletes were found to generate less force from their leg muscles after static stretching than they did after having not stretched at all. Other studies have shown static stretching can also have unwanted effects on lower limb power, sprinting ability and vertical jump, with some studies reporting that this type of stretching decreased muscle strength by as much as 30 percent.

That muscle weakness might be due to the fact that static stretches elongate muscle fibers, thereby lowering the fibers’ concentration of power. Additional research has determined something called a neuromuscular inhibitory response could also account for a decrease in muscle strength. This means the stretched muscle becomes temporarily weaker and less responsive, causing the central nervous system to reduce the strength of other muscles — potentially even on the opposite side of the body — as the body tries to restore balance and protect itself from injury.

But static stretching doesn’t only affect strength and power, it can also impact endurance. In 2010, researchers at Florida State University found that trained distance runners participating in a time trial became about five percent less efficient and covered three percent less distance if they did static stretches before the run. The conclusion was that the runners who practiced static stretches beforehand ultimately covered less ground but used more energy to do so than they would have otherwise.

It’s not likely you’re a trained distance runner or looking to become one, but the stretching debate and its outcomes are important to anyone who wants to exercise effectively and remain injury-free. If you do choose to incorporate stretching into your fitness routine, always start with 10 to 15 minutes of aerobic exercise (such as slow jogging) that will elevate your heart rate and warm up your muscles. Then choose dynamic stretches that are specific to your sport or activity to ensure you’re preparing the muscles you’re about to work. Always stretch with controlled movements, rather than momentum, and practice constant biofeedback. In other words, if a movement goes beyond discomfort and into pain, stop immediately.